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Introduction: Previous research has shown that health care access and usage patterns among Native Americans are often difficult to measure. Hypothesis: We hypothesize that sociodemographic factors such as age, gender, education, and employment influence health care access and usage patterns in Native communities in the Strong Heart Study (SHS). Methods: The SHS is a prospective population-based epidemiological study of cardiovascular disease and its associated risk factors in American Indians (AI). Between 1997 and 1999, surviving participants (N=2,382) of the original cohort were invited to a third exam, in which health care access and usage information were collected, along with other clinical and sociodemographic measurements. Multivariate logistic regression was used to find influencing factors of health care choices. Results: The majority of study participants (79%, 1,877/2,382) reported Indian Health Services (IHS) as their primary source of care, and close to one-third (29%, 689/2,358) reported having no additional coverage. Figure 1 showed travel time, waiting time after arriving at the clinics, and waiting time of a walk-in visit in IHS, tribal health service, and private practice. As participants aging or obtaining more years of education, they were less likely to use public (IHS or tribal) health service vs. private practice with odds ratio (95% confidence interval) 0.97 (0.95-0.99, p Conclusions: SHS participants primarily utilize IHS compared to other health services. Average waiting time is longer for IHS facilities (vs. private practice or tribal health facilities) with 35% (622/1,760) participants waiting for > 60 minutes to be seen in regular appointments, and with 53% (814/1,540) participants waiting for > 60 minutes in a walk-in visit. Age and education influence access to and selection of health care services for AI. This report provides baseline information for future health care access study in SHS.

Telomeres shorten with age and shorter leukocyte telomere length (LTL) has been associated with various age-related diseases. Thus, LTL has been considered a biomarker of biological aging. Dyslipidemia is an established risk factor for most age-related metabolic disorders. However, little is known about the relationship between LTL and dyslipidemia. Lipidomics is a new biochemical technique that can simultaneously identify and quantify hundreds to thousands of small molecular lipid species. In a large population comprising 1843 well-characterized American Indians in the Strong Heart Family Study, we examined the lipidomic profile of biological aging assessed by LTL. Briefly, LTL was quantified by qPCR. Fasting plasma lipids were quantified by untargeted liquid chromatography–mass spectrometry. Lipids associated with LTL were identified by elastic net modeling. Of 1542 molecular lipids identified (518 known, 1024 unknown), 174 lipids (36 knowns) were significantly associated with LTL, independent of chronological age, sex, BMI, hypertension, diabetes status, smoking status, bulk HDL-C, and LDL-C. These findings suggest that altered lipid metabolism is associated with biological aging and provide novel insights that may enhance our understanding of the relationship between dyslipidemia, biological aging, and age-related diseases in American Indians. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11357-022-00638-9.

American Indians (AI) have a high prevalence of diabetes, obesity, cardiovascular disease (CVD), and chronic kidney disease. Inclusion of kidney function and other population-specific characteristics in equations used to predict atherosclerotic CVD (ASCVD) risk may help define risk more accurately in populations with these chronic diseases. We used data from the Strong Heart Study (SHS), a population-based longitudinal cohort study of AI, to modify the American College of Cardiology/American Heart Association (ACC/AHA) Pooled Cohort ASCVD risk equations and then explored the performance of the new equations in predicting ASCVD in AI. The study included baseline SHS exam data from 4213 individuals between 45 and 75 years of age, collected in 13 communities from 3 geographic areas in the United States and spanning a wide range of tribal backgrounds, with continuous follow-up data from 1989 to 2015. Using SHS data for blood pressure, diabetes, cholesterol, smoking, and renal function, Cox proportional hazard models were developed to predict ASCVD-free time for AI men and women. ASCVD risk in AI calculated using the SHS-modified equations were compared to risk calculated using the ACC/AHA pooled cohort equations for African Americans (AAs) and Whites. Goodness-of-fit measures for ASCVD risk prediction showed that the SHS-modified equations fit the data from the SHS better than the ACC/AHA equations for AAs and Whites. Adjusting risk prediction equations using population data from the SHS and including measures of renal function significantly improved ASCVD risk prediction in our AI cohort.

Introduction: Dyslipidemia is characterized by high levels of total cholesterol (TC), LDL cholesterol (LDL-C), triglycerides (TG), or low levels of HDL cholesterol (HDL-C) and is an established risk factor for subclinical and clinical cardiovascular disease (CVD) among adults. Although several investigations exist in older American Indian (AI) adults, the data on AI adolescents and young adults are scarce. Hypothesis: Dyslipidemia will be prevalent, and the incidence of subclinical and clinical CVD will be higher in young AI with than without baseline dyslipidemia. Methods: We evaluated AI participants from the SHFS, who were 14-39 years old at the baseline examination, 2001-2003 (n=1,436). To measure lipids, we drew blood after a 12-hour fast and defined dyslipidemia as any of the following: TC ≥ 200 mg/dL, LDL-C ≥ 100 mg/dL, TG ≥ 150 mg/dL, HDL-C < 40 mg/dL for men, HDL-C < 50mg/dL for women, non-HDL-C ≥ 130 mg/dL or taking lipid lowering medication. We used carotid ultrasound to detect atherosclerotic plaque at baseline and at the follow-up examination, 2006-2009. We identified CVD events through 2019 with a median follow-up of 17.8 years. We used log-rank tests to determine if the incidence of plaque or CVD events differed according to different categories of dyslipidemia. Results: Prevalence of dyslipidemia was 42%, 65%, and 73% for participants Conclusions: AI adolescents and young adults have an unexpectedly high prevalence of dyslipidemia, which leads to higher incident plaque and CVD events later in life. These data provide evidence for the benefits of lipid screening and intervention among this population.

Background: Dyslipidemia is a major risk factor for CVD. Left ventricular mass (LVM) is an independent predictor of heart failure and other cardiovascular events. It is unclear whether and how altered plasma lipidome (all lipids in a plasma sample) affects LVM. The relationship between longitudinal change in plasma lipidome and change in LVM is also unstudied in any racial/ethnic group. Objective: To identify molecular lipid species associated with LVM, independent of traditional risk factors. Methods: Using an untargeted LC-MS, we repeatedly measured 1,542 lipids in 3,162 fasting plasma samples collected at two time points (2001-2003, 2006-2009, mean 5.5 years apart) from 1,581 American Indians in the Strong Heart Family Study. All participants were free of overt CVD at both time points. LVM was measured by M-mode echocardiography and LVM index (LVMI) was calculated as LVM/height 2.7 . Lipids associated with LVMI were identified by generalized estimating equation (GEE) models, adjusting for age, sex, center, BMI, smoking, blood pressure, renal function, LDL-c, and diabetes. We first conducted the analysis at each time point, separately, and then combined the results by meta-analysis. The longitudinal association between change in lipids and change in LVMI was examined by GEE, adjusting for the same covariates plus baseline lipids and LVMI. Multiple testing was controlled by false discovery rate at 0.05. Results: The mean age of participants was 39.8 years (62.5% women) at baseline and 45.1 years at follow-up. We identified 325 lipids (125 known), largely fatty acyls, sterol lipids, sphingolipids, glycerolipids, and glycerophospholipids, significantly associated with LVMI at both time points. Longitudinal changes in 17 lipids, including glycerolipids, glycerophospholipids, and sphingolipids, were either positively (ORs: 1.09 -1.95) or negatively (ORs: 0.50 - 0.69) associated with change in LVMI over 5 years of follow-up. Changes in lipids explain up to 1.58% of the variability in the change of LVMI during follow-up. Additional adjustments for use of anti-hypertensive and lipid-lowering drugs did not change the results. Conclusion: Altered fasting plasma lipidome and its longitudinal change over time were significantly associated with LVMI beyond clinical factors and baseline lipids. Our results shed light on the mechanisms through which dyslipidemia may affect LV remodeling, thereby contributing to heart failure or other cardiovascular events.

Rates of cardiovascular disease (CVD) among American Indians (AI) have been increasing. Although we have observed an association between atherosclerosis and CVD in older adults, the potential association among young AI is unclear. Therefore, we aim to describe the prevalence of atherosclerosis among young AI and determine its association with CVD and all-cause mortality.We evaluated AI participants from the Strong Heart Family Study (SHFS), who were40 years old and CVD free at the baseline examination, 2001-2003 (n = 1376). We used carotid ultrasound to detect baseline atherosclerotic plaque. We identified CVD events and all-cause mortality through 2019, with a median follow-up of 17.8 years. We used shared frailty Cox Proportional Hazards models to assess the association between atherosclerosis and time to CVD event or all-cause mortality, while controlling for covariates. Among 1376 participants, 71 (5.2%) had atherosclerosis at baseline. During follow-up, 120 (8.7%) had CVD events and 104 (7.6%) died from any cause. CVD incidence was higher in participants who had baseline atherosclerosis (13.51/1000 person-years) than in those who did not (4.95/1000 person-years, p = 0.0003). CVD risk and all-cause mortality were higher in participants with atherosclerosis, while controlling for covariates (CVD HR = 1.85, 95%CI = 1.02-3.37, p = 0.0420; all-cause mortality HR = 2.04, 95%CI = 1.07-3.89, p = 0.0291).Among young AI, atherosclerosis was independently associated with incident CVD and all-cause mortality later in life. Thus, atherosclerosis begins early in life and interventions in adolescents and young adults to slow the progression of disease could prevent or delay CVD events later in life.

Introduction: Rates of cardiovascular disease (CVD) among American Indians (AI) have been increasing. Subclinical atherosclerosis is typically detected later in life and may develop into clinical CVD. Although investigators have established the association in older adults, the burden of subclinical atherosclerosis and its relation to CVD risk among AI youth is unclear. Hypothesis: Subclinical atherosclerosis will be prevalent and the risk of CVD will be higher in AI with atherosclerotic plaque in adolescence and early adulthood. Methods: We evaluated AI participants from the SHFS, who were 14-39 years old, CVD free, and had a carotid ultrasound at the baseline examination, 2001-2003 (n=1,376). We used carotid ultrasound to detect baseline atherosclerotic plaque. We identified fatal and/or non-fatal CVD events through the end of 2019 with a median follow-up of 17.8 years. We used shared frailty Cox Proportional Hazards models to assess the association between subclinical atherosclerosis and time to CVD events, while controlling for covariates. Results: Among 1,376 participants, 71 (5.2%) had atherosclerotic plaque at baseline. During follow-up, 120 (8.7%) participants had a fatal or non-fatal CVD event. CVD incidence was higher in participants with baseline plaque (13.51/1,000 person-years) than in those without (4.95/1,000 person-years, p=0.0003, Figure 1). Risk of CVD was higher in participants with baseline plaque compared to those without, while controlling for age and obesity (CVD HR=1.85, 95% CI=1.02-3.37, p=0.0420). Conclusions: AI adolescents and young adults have an unexpectedly high prevalence of atherosclerotic plaque, which is independently associated with incident CVD later in life. Thus, atherosclerosis begins early in life and interventions in adolescents and young adults to slow the progression of disease could prevent or delay CVD events later in life.

Background: Dyslipidemia is an established risk factor for CVD. Standard lipid panel lacks description of the full spectrum of blood lipids. A longitudinal profiling of blood lipidome in relation to the risk of CVD is lacking in any racial/ethnic groups. Objective: Identify novel lipid species associated with risk of CVD in American Indians, independent of traditional risk factors (TRFs). Method: Using untargeted LC-MS, we repeatedly measured 1,542 lipid species in 3,916 fasting plasma samples from 1,958 participants who attended two exams (~5.5 years apart) and were followed up to 18 years in the Strong Heart Study. Elastic net was used to select baseline lipids and change in lipids (baseline to 5-year follow-up) associated with 18-year risk of CVD. Multivariate and network analyses were conducted to identify discriminatory lipidomic signatures and differential lipid networks associated with risk of CVD. Results: Of 1,911 participants free of CVD at both baseline (2001-2003) and 5-year follow-up (2006-2009), 222 developed CVD after 18 years of follow-up. High-resolution LC-MS detected 1,542 lipid species (518 known). After adjusting for TRFs (age, sex, center, smoking, BMI, hypertension, diabetes, LDL-c, and albuminuria), elevated baseline levels of 21 known lipids, including cholesterol esters, sphingolipids, glycerophospholipids, and fatty acids, were significantly associated with increased (HR: 1.08 to 1.26) or decreased (HR: 0.81 to 0.91) risk of CVD. Longitudinal change in 13 lipids, including cholesterol esters, sphingolipids, glycerophospholipids, and fatty acids, were either positively (HR: 1.03 to 1.28) or inversely (HR: 0.75 to 0.92) associated with risk of CVD at 18-year follow-up. A lipid score comprising 10 baseline lipids significantly improved risk prediction beyond TRFs (ROC increases from 0.823 to 0.837, P = 0.009). Multivariate and network analyses identified distinct lipidomic signatures and lipid networks associated with risk of CVD. Conclusion: Novel molecular lipids significantly predict risk of CVD beyond TRFs in American Indians. Our findings provide novel lipid molecules for risk stratification and shed light on the mechanism linking lipid dysregulation to CVD in American Indians.

Background: Dyslipidemia is an established risk factor for atherosclerotic CVD, but full identification of circulating molecular lipids associated with atherosclerosis is still lacking in any racial/ethnic group. Objective: Prospectively identify lipid species associated with risk of atherosclerosis in American Indians. Methods: Using an untargeted LC-MS, we repeatedly measured 3,891 paired fasting plasma samples from 1,950 American Indians at two exams (~5.5 year apart) in the Strong Heart Family Study. Carotid atherosclerosis was assessed by carotid ultrasonography. Incident carotid atherosclerosis was identified if plaque was absent at baseline but detected at follow-up. Elastic net model was used to select baseline lipids or change in lipids (baseline to follow-up) associated with risk for atherosclerosis beyond traditional risk factors (TRFs) including age, sex, center, smoking, BMI, hypertension, diabetes, LDL-c and albuminuria. Multivariate analysis was used to identify lipidomic signatures associated with risk for carotid atherosclerosis. Results: Of 1,319 participants with no evident plaque at baseline (2001-2003), 270 developed incident carotid atherosclerosis at 5-year follow-up (2006-2009). Of 518 known lipids detected, altered baseline levels of 29 lipid species, largely glycerophospholipids and glycerolipids, were significantly associated with risk of atherosclerosis beyond TRFs (HR: 1.06-1.33 for risk lipids; 0.85-0.93 for protective lipids). A lipid score comprising top 5 baseline lipids improves risk prediction beyond TRFs (ROC increases from 0.79 to 0.80, P = 0.03). Longitudinal changes in 20 lipids, mainly glycerophospholipids, were significantly associated with risk of atherosclerosis after adjusting for TRFs and baseline lipids. Multivariate analysis identified distinct lipidomic signatures associated with atherosclerosis. Conclusion: Altered baseline lipids were independently associated with prevalent and incident carotid atherosclerosis in American Indians. Our findings shed light on the mechanisms linking dyslipidemia to atherosclerosis and provide instrumental data for risk stratification and therapeutic targets customized to American Indians.

OBJECTIVE Comprehensive assessment of alterations in lipid species preceding type 2 diabetes (T2D) is largely unknown. We aimed to identify plasma molecular lipids associated with risk of T2D in American Indians. RESEARCH DESIGN AND METHODS Using untargeted liquid chromatography–mass spectrometry, we repeatedly measured 3,907 fasting plasma samples from 1,958 participants who attended two examinations (∼5.5 years apart) and were followed up to 16 years in the Strong Heart Family Study. Mixed-effects logistic regression was used to identify lipids associated with risk of T2D, adjusting for traditional risk factors. Repeated measurement analysis was performed to examine the association between change in lipidome and change in continuous measures of T2D, adjusting for baseline lipids. Multiple testing was controlled by false discovery rate at 0.05. RESULTS Higher baseline level of 33 lipid species, including triacylglycerols, diacylglycerols, phosphoethanolamines, and phosphocholines, was significantly associated with increased risk of T2D (odds ratio [OR] per SD increase in log2-transformed baseline lipids 1.50–2.85) at 5-year follow-up. Of these, 21 lipids were also associated with risk of T2D at 16-year follow-up. Aberrant lipid profiles were also observed in prediabetes (OR per SD increase in log2-transformed baseline lipids 1.30–2.19 for risk lipids and 0.70–0.78 for protective lipids). Longitudinal changes in 568 lipids were significantly associated with changes in continuous measures of T2D. Multivariate analysis identified distinct lipidomic signatures differentiating high- from low-risk groups. CONCLUSIONS Lipid dysregulation occurs many years preceding T2D, and novel molecular lipids (both baseline level and longitudinal change over time) are significantly associated with risk of T2D beyond traditional risk factors. Our findings shed light on the mechanisms linking dyslipidemia to T2D and may yield novel therapeutic targets for early intervention tailored to American Indians.

Non-caloric artificial sweeteners (NAS) are marketed as healthier alternatives to sugar, but the relationship between consumption of NAS and development of diabetes is unclear. This study assessed the associations of diet soda and NAS consumption with (1) early markers of insulin and glucose homeostasis (cross-sectionally) and (2) incident diabetes (over an average of 8 years of follow-up) among American Indians, a population with high rates of obesity. The study population included Strong Heart Family Study participants without cardiovascular disease or diabetes who participated in the 2007–2009 study exam (n = 1359). Diet soda and NAS consumption were assessed using a Block food frequency questionnaire and supplemental NAS questionnaire at the study exam. Fasting plasma glucose and insulin were measured during the study exam after a 12-h overnight fast. Participants were followed for incident diabetes through December 2017 using a single phone interview and medical record review; diabetes was identified by self-report and confirmed by documentation in medical records. Associations of diet soda and NAS consumption with fasting insulin, glucose, and incident diabetes were assessed using generalized estimating equations (fasting insulin and glucose analyses) and parametric survival models with Weibull distributions (incident diabetes analyses). Just under half of participants reported regularly consuming diet soda (40%) or using NAS to sweeten their beverages (41%). During an average 8 years of follow-up, we identified 98 cases of incident diabetes. After correction for multiple comparisons, there were no statistically significant associations of reported diet soda and NAS consumption with fasting insulin, fasting glucose, or incident diabetes. Although reported consumption of diet soda and NAS were high, neither were associated with diabetes risk.

The objective of this study was to investigate whether leukocyte telomere length (LTL) predicts the risk for cancer mortality among American Indians participating in the Strong Heart Study (1989–1991). Participants (aged 45–74 years) were followed annually until December 2015 to collect information on morbidity/mortality. LTL was measured by qPCR using genomic DNA isolated from peripheral blood. The association between LTL and risk for cancer mortality was examined using a multivariable Cox proportional hazard model, adjusting for age, gender, education, study site, smoking, alcohol use, physical activity, systolic blood pressure, fasting blood glucose, obesity, and low- and high-density lipoprotein. Of 1945 participants (mean age 56.10 ± 8.17 at baseline, 57% women) followed for an average 20.5 years, 220 died of cancer. Results showed that longer LTL at baseline significantly predicts an increased risk of cancer death among females (HR 1.57, 95% CI 1.08–2.30), but not males (HR 0.74, 95% CI 0.49–1.12) (p for interaction 0.009). Specifically, compared with the women with the longest LTL (fourth quartile), those in the third, second, and first quartiles showed 53%, 41%, and 44% reduced risk for cancer death, respectively. The findings highlight the importance of sex-specific analysis in future telomere research.

Background Myocardial energetic efficiency (MEE), is a strong predictor of CV events in hypertensive patient and is reduced in patients with diabetes and metabolic syndrome. We hypothesized that severity of insulin resistance (by HOMA-IR) negatively influences MEE in participants from the Strong Heart Study (SHS). Methods We selected non-diabetic participants (n = 3128, 47 ± 17 years, 1807 women, 1447 obese, 870 hypertensive) free of cardiovascular (CV) disease, by merging two cohorts (Strong Heart Study and Strong Heart Family Study, age range 18–93). MEE was estimated as stroke work (SW = systolic blood pressure [SBP] × stroke volume [SV])/“double product” of SBP × heart rate (HR), as an estimate of O2 consumption, which can be simplified as SV/HR ratio and expressed in ml/sec. Due to the strong correlation, MEE was normalized by left ventricular (LV) mass (MEEi). Results Linear trend analyses showed that with increasing quartiles of HOMA-IR patients were older, more likely to be women, obese and hypertensive, with a trend toward a worse lipid profile (all p for trend Conclusions Severity of insulin resistance has significant and independent negative impact on myocardial mechano-energetic efficiency in nondiabetic individual from a population study of American Indians. Trial registration number NCT00005134, Name of registry: Strong Heart Study, URL of registry: https://clinicaltrials.gov/ct2/show/NCT00005134, Date of registration: May 25, 2000, Date of enrolment of the first participant to the trial: September 1988

Dyslipidemia associates with and usually precedes the onset of chronic kidney disease (CKD), but a comprehensive assessment of molecular lipid species associated with risk of CKD is lacking. Here, we sought to identify fasting plasma lipids associated with risk of CKD among American Indians in the Strong Heart Family Study, a large-scale community-dwelling of individuals, followed by replication in Mexican Americans from the San Antonio Family Heart Study and Caucasians from the Australian Diabetes, Obesity and Lifestyle Study. We also performed repeated measurement analysis to examine the temporal relationship between the change in the lipidome and change in kidney function between baseline and follow-up of about five years apart. Network analysis was conducted to identify differential lipid classes associated with risk of CKD. In the discovery cohort, we found that higher baseline level of multiple lipid species, including glycerophospholipids, glycerolipids and sphingolipids, was significantly associated with increased risk of CKD, independent of age, sex, body mass index, diabetes and hypertension. Many lipid species were replicated in at least one external cohort at the individual lipid species and/or the class level. Longitudinal change in the plasma lipidome was significantly associated with change in the estimated glomerular filtration rate after adjusting for covariates, baseline lipids and the baseline rate. Network analysis identified distinct lipidomic signatures differentiating high from low-risk groups. Thus, our results demonstrated that disturbed lipid metabolism precedes the onset of CKD. These findings shed light on the mechanisms linking dyslipidemia to CKD and provide potential novel biomarkers for identifying individuals with early impaired kidney function at preclinical stages.

Introduction: Leukocyte telomere length (LTL) is a potential biomarker of aging and associated with several age-related diseases. Current research on an association between LTL and incident stroke has had inconclusive results. We hypothesized that LTL is associated with incident stroke among American Indians (AI) in the Strong Heart Family Study (SHFS). Methods: The SHFS is a population-based cohort study of cardiovascular disease (CVD) and its risk factors. Participants (n=2,769) recruited from regions in Arizona, Oklahoma and the Dakotas were assessed for LTL and CVD risk factors during a clinic visit between 2001 and 2003. Incident stroke events were identified through the end of 2018 (mean follow-up: 16.4 years). We assessed the association between LTL and incident stroke using frailty models based on the proportional hazards, accounting for family relatedness and established stroke risk factors that include sex, geographical location, education, smoking, atrial fibrillation, diabetes mellitus, and hypertension. Results: Among 2,769 participants, the mean age was 40.6±17.2 and 41.4% were male. During follow-up, there were 79 (2.9%) incident stroke cases. In the primary model, which adjusted for demographic variables (sex, location and education), the hazard ratios (HR) for stroke in participants in the first and second LTL quartiles were significantly higher than those in the highest (longest) LTL quartile, with HRs of 3.1 (95%CI: 1.4 - 6.6) and 3.5 (95%CI: 1.7 - 7.5), respectively. After adjusting for smoking, atrial fibrillation, diabetes mellitus, and hypertension, the association between LTL and stroke was attenuated, but remained significant when comparing the second shortest LTL quartile to the longest LTL quartile, HR: 2.3 (95% CI: 1.1 – 5.0). Conclusions: In summary, LTL was associated with incident stroke among SHFS participants. Those with shorter LTL have higher risk of stroke. Longer follow-up time may add more power to data analyses since the SHFS is relatively young, with an average baseline age of 40 years. If results are confirmed in other populations, LTL may serve as a biomarker identifying high risk individuals for the purpose of stroke prevention.

Background: American Indians (AIs) suffer disproportionately high rate of type 2 diabetes (T2D). Traditional biomarkers have limited value in predicting and tracking early onset and progression of T2D. There is an urgent need for early biomarkers in this high-risk but understudied minority population. Objective: To identify novel lipids predictive of T2D onset among American Indians, independent of standard risk factors. Methods: We studied 2,000 American Indians attending two clinical exams (2001-2003, 2006-2009, average 5-yr apart) in the Strong Heart Family Study (SHFS). Fasting plasma lipids were repeatedly measured by untargeted lipidomics using LC-MS/MS. All participants were free of overt CVD at baseline (2001-2003) and followed through 2017 (average 16-yr follow-up). Cox regression with frailty model was used to identify lipids predictive of T2D onset, adjusting for traditional risk factors including age, sex, smoking, BMI, triglyceride, HDL, insulin resistance, eGFR and dietary intake of protein. Longitudinal analysis was conducted by regressing changes in lipids on changes in T2D-related traits (e.g., fasting glucose, HbA1c, or insulin resistance) between baseline and 5-yr follow-up, adjusting for changes in BMI, triglyceride, HDL, and eGFR. Incremental prognostic value of lipids in diabetes risk prediction above traditional risk factors was estimated using area under the curve (AUC). Network analysis was conducted to examine the dynamic changes in lipid networks between baseline and 5-yr follow-up. Multiple testing was controlled by FDR. Results: Of 1,628 non-diabetic participants at baseline (mean age 39.8, 62% women), 189 and 359 individuals developed incident T2D after 5-yr and 16-yr follow-up, respectively. Our high-resolution lipidomics detected 1,826 lipids, of which 1,119 lipids (460 known, 659 unknown) passed stringent quality control. Seven lipids with known structures significantly predict over 30% increased (FA(18:1), FA(20:2), FA(22:2), SM(d34:0) ) or 19% decreased (PC(37:4), PC(37:5), PC(38:4)) risk of T2D onset at both follow-ups. Nine unknown lipids also predicted T2D onset. Longitudinal changes in CE(20:2), CE(22:6), PC(32:0) and two unknowns explain about 6.4% changes in fasting plasma glucose. These newly identified lipids significantly improve the performance of risk prediction over traditional risk factors (AUC increased from 0.787 to 0.803, P=0.002). Network topology analysis revealed that the network connectivity among lipids was much stronger in participants who developed new T2D compared to those who didn’t (degree of network connectivity, 4.2 vs 2.5, P Conclusion: We identified several novel plasma lipids significantly predictive of incident T2D, independent of traditional risk factors. These findings highlight the importance of identifying novel lipid markers in early diabetes risk prediction.

Background: Biological aging assessed by both leukocyte telomere length (LTL) and DNA methylation (DNAm) has been associated with CVD and its risk factors. Moreover, LTL is epigenetically regulated. We hypothesized that LTL-associated epigenetic changes are associated with risk of CVD in the community. Objective: To test whether LTL-associated loci are associated with incident CVD, independent of standard risk factors in multi-ethnic cohorts. Method: We evaluated 3,628 participants with complete LTL and DNAm data in four prospective cohorts, including 1,531 American Indians from the Strong Heart Study (SHS, mean age 56, 60% women), 821 non-Hispanic Whites (NHW) from the Framingham Heart Study (FHS, mean age 60, 51% women), 471 NHW, 150 Hispanics, and 162 African Americans from the Multi-ethnic Study of Atherosclerosis (MESA, mean age 70 , 55% women), and 471 NHW and 342 African Americans from the Women’s Health Initiative (WHI, mean age 65 , all women). LTL was quantified by qPCR (SHS, MESA) or Southern blot (FHS, WHI). DNAm was assayed by Illumina EPIC (SHS) or 450K (FHS, MESA and WHI) arrays. We imputed 450K to 850K using random forest algorithms. CVD events included fatal and nonfatal MI, CHD, heart failure, stroke, peripheral artery diseases, and cardiovascular deaths. Cohort-specific EWAS was conducted to identify CpGs associated with LTL, adjusting for age, sex, race/ethnicity, smoking, alcohol, BMI, site, cell proportion, and batch. Multiple testing was Bonferroni-corrected (genome-wide P < 2.4 x10 -7 ). Results across studies were combined by random-effects meta-analysis. To examine whether LTL-associated epigenetic loci are associated with CVD risk, we used a weighted methylation score to predict incident CVD by Cox regression, adjusting for age, sex, site, smoking, alcohol, BMI, glucose, SBP, LDL-C, and total cholesterol. Results: We ascertained 2,001 CVD events, including 986 in the SHS (average follow-up 15.2 years), 208 in FHS (average follow-up 7.7 years), 74 in MESA (average follow-up 4.9 years), and 733 in WHI (average follow-up 12.2 years). Meta-EWAS identified 22 CpGs (mapped to 17 unique genes) associated with LTL. Of these, 19 loci (15 negatively and 4 positively associated with LTL) had consistent directionality of association across four cohorts. The most significant genes harboring altered CpG sites included TLL2 (cg10549018, P= 2.42 x 10 -12 ) and TPST1 ( cg10691866, P =8.6 x 10 -10 ). A higher composite methylation score, which reflects longer LTL ( P Conclusion: Altered DNA methylation at 19 CpG loci was significantly associated with LTL. Their combined effects may predict a reduced risk of CVD. The observed associations warrant further investigation.

Introduction: About 30% of all U.S. adults and 70-80% of those with Type 2 diabetes mellitus (T2DM) have non-alcoholic fatty liver disease (NAFLD). Atherosclerotic cardiovascular disease (CVD) is more common among NAFLD patients, albeit with limited evidence from large prospective studies. Hypothesis: American Indians (AI) with NAFLD would be more likely to develop carotid atherosclerosis given their high prevalence of obesity and T2DM. Methods: The Strong Heart Family Study (SHFS) is a population-based family study of CVD and its risk factors in AI. Participants (n=2786; 59.6% female, mean age 40.8 ±17.3 y) were recruited from 12 tribes in 3 regions: Arizona, North/South Dakota, and Oklahoma. Carotid ultrasound-assessed plaque and plaque score were obtained at the baseline examination in 2001-03, and again in surviving participants (n=2406) from 2006 to 2009. NAFLD prevalence was estimated using hepatic steatosis index (HSI). NAFLD fibrosis score was used to separate NAFLD patients with or without advanced fibrosis. HSI is calculated using serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), BMI, diabetes status, and sex, while the NAFLD fibrosis score is derived from age, BMI, diabetes status, ALT, AST, platelet count, and serum albumin. Plaque progression was defined as any increase in plaque score (0 to 8 carotid segments with plaque) from baseline to the second examination. Frailty model was used in data analyses to account for the relatedness among family members. Results: Mean BMI of participants was 31.3 ± 7.5 kg/m 2 , 19% had T2DM, 32.6% were hypertensive, and 36.3% were current smokers. NAFLD prevalence (HSI > 36) was 78%, while 6% did not have NAFLD (HSI < 30) and 16% participants were in an intermediate category (HSI 30-36). Among participants with NAFLD (n=2096), three fibrosis classes were defined by NAFLD fibrosis scores: 1 no to moderate fibrosis (61%, fibrosis score < -1.455), 2 indeterminate (31%, -1.455 ≤ fibrosis score ≤ 0.676), and 3 cirrhosis or severe cirrhosis (8%, fibrosis score > 0.676). About 31% of participants had carotid atherosclerosis (plaque score ≥ 1) at baseline. About 14% of the 2252 participants who had two carotid ultrasound evaluations had plaque progression and 19% of those without carotid atherosclerosis at baseline (n=1571) had incident plaque at the second visit. Compared to those with no to moderate fibrosis, those who had cirrhosis or severe cirrhosis had higher risks of plaque progression with a hazard ratio (HR, 95% CI) of 1.8 (1.1-2.9, P=0.026), and of incident plaque with a HR (95% CI) of 2.6 (1.5-4.6, P=0.0009), adjusted for sex, smoking, hypertension, albuminuria, LDL-C, and HDL-C. Similar results were found among participants with intermediate fibrosis scores. Conclusions: The prevalence of HSI-defined NAFLD is high in AI. NAFLD fibrosis score predicts both incident and progressive carotid atherosclerosis.

The aim of this study was to investigate whether red meat consumption is related to changes in left ventricular mass (LVM), left atrial diameter and carotid atherosclerosis in American Indians.We prospectively analyzed echocardiographic and carotid ultrasound data of 1090 adults aged 40 years and older enrolled in the Strong Heart Family Study who were free of cardiovascular disease at baseline - 535 (49%) were hypertensive and 555 (51%) participants were nonhypertensive. Processed and unprocessed red meat intake was ascertained by using a Block food-frequency questionnaire at baseline. Cardiac and vascular biomarkers were assessed at baseline and 4 years later. Marginal models with multivariate adjustment were used to assess the associations of red meat intake with LVM, left atrial diameter, intima-media thickness and presence and extent of carotid atherosclerosis.Participants with hypertension were older, had a higher BMI, were more likely to be diabetic and less physically active. Processed and unprocessed red meat consumption was related to an increase in the presence of atherosclerotic plaques in male and female hypertensive individuals. In male hypertensive participants, processed meat intake was further observed to be associated with an increase in intima-media thickness, atrial diameter but not LVM. In nonhypertensive participants, neither unprocessed nor processed red meat intake was associated with changes in cardiac parameters or carotid atherosclerosis.Over a 4-year period, red meat consumption was related to cardiovascular target organ damage in hypertensive American Indians. These findings emphasize the importance of dietary measures for cardiovascular disease prevention.

Background Recent analyses in a registry of hypertensive patients suggested that preceding left ventricular (LV) hypertrophy (LVH) and/or carotid atherosclerosis are associated with incident type 2 diabetes, independent of confounders. We assess the relation between prevalent cardio-renal target organ damage (TOD) and subsequent incident type 2 diabetes in a population-based study with high prevalence of obesity. Methods We selected 2887 non-diabetic participants from two cohorts of the Strong Heart Study (SHS). Clinical exam, laboratory tests and echocardiograms were performed. Adjudicated TODs were LVH, left atrium (LA) dilatation, and high urine albumin/creatinine ratio (UACR). Multivariable logistic regression models were used to identify variables responsible for the association between initial TODs and incident diabetes at 4-year follow-up (FU). Results After 4 years, 297 new cases of diabetes (10%) were identified, 216 of whom exhibited baseline impaired fasting glucose (IFG, 73%, p Conclusions In this population-based study with high prevalence of obesity, TOD precedes clinical appearance of type 2 diabetes and is related to the preceding metabolic status, body composition and inflammatory status. Trial registration Trial registration number: NCT00005134, Name of registry: Strong Heart Study, URL of registry: https://clinicaltrials.gov/ct2/show/NCT00005134, Date of registration: May 25, 2000, Date of enrolment of the first participant to the trial: September 1988

Introduction: Non-alcoholic fatty liver disease has been associated with an increased risk of cardiovascular disease (CVD). Levels of the circulating hepatic enzymes aspartate amino transferase (AST) and alanine amino transferase (ALT) are used as non-invasive biomarkers of liver fat and fibrosis. A number of studies have investigated the potential for these biomarkers of liver function, as well as their ratio AST/ALT, to predict CVD risk, with equivocal results. We hypothesized that these measurements might be important biomarkers of CVD in American Indians (AI) who experience high rates of both liver disease and type 2 diabetes-related CVD. Methods: The Strong Heart Family Study (SHFS) is a population-based family study of heart disease and its risk factors in AI. Participants (n=2760) were recruited from 12 tribes located within 3 geographical regions in Arizona, North/South Dakota, and Oklahoma. Circulating biomarkers and metabolic measures were assessed during a clinic visit in 2001-2003. Participants were followed for morbidity and mortality events until the end of 2016. Median follow-up time was 14.5 years. Results: In this study, 59.8% were female, mean (± standard deviation) age was 40.8 ±17.2 years, mean BMI was 31.3 ± 7.5 kg/m 2 , 19% had type 2 diabetes (T2D), 32.6% were hypertensive, and 36.1% were current smokers. In univariate analyses, higher ALT and AST levels (IU/L) were associated with all components of the metabolic syndrome (MS), i.e., increased waist circumference, triglycerides, blood pressure, fasting glucose, and decreased HDL-C; all p Conclusions: In American Indians of the SHFS, liver function biomarkers are significantly associated with metabolic syndrome and its components, and predict all-cause and cardiovascular mortality, suggesting that common mechanisms impact MS-related CVD risk factors and liver disease biomarker levels in this high-risk population.

Telomere length, a marker of biological aging, has been associated with cardiovascular disease (CVD). Increased arterial stiffness, an indicator of arterial aging, predicts adverse CVD outcomes. However, the relationship between telomere length and arterial stiffness is less well studied. Here we examined the cross-sectional association between leukocyte telomere length (LTL) and arterial stiffness in 2,165 American Indians in the Strong Heart Family Study (SHFS). LTL was measured by qPCR. Arterial stiffness was assessed by stiffness index β. The association between LTL and arterial stiffness was assessed by generalized estimating equation model, adjusting for sociodemographics (age, sex, education level), study site, metabolic factors (fasting glucose, lipids, systolic blood pressure, and kidney function), lifestyle (BMI, smoking, drinking, and physical activity), and prevalent CVD. Results showed that longer LTL was significantly associated with a decreased arterial stiffness (β=-0.070, P=0.007). This association did not attenuate after further adjustment for hsCRP (β=-0.071, P=0.005) or excluding participants with overt CVD (β=-0.068, P=0.012), diabetes (β=-0.070, P=0.005), or chronic kidney disease (β=-0.090, P=0.001). In summary, shorter LTL was significantly associated with an increased arterial stiffness, independent of known risk factors. This finding may shed light on the potential role of biological aging in arterial aging in American Indians.

Purpose The purpose of this study is to characterize risk factors associated with type 2 diabetes in young adults aged 18 to 29 years to develop a noninvasive risk assessment tool for use with younger American populations. Methods The self-assessment tool was developed with the Strong Heart Family Study data. A total of 590 young American Indian adults (242 men) who had normoglycemia and were not receiving diabetes treatment were included. Risk factors recommended by the American Diabetes Association were used to assess diabetes risk in these young adults. A logistic regression model was developed to calculate the predicted probability. The area under the receiver operating characteristic curve was used to evaluate the model. Results The final model showed that parental history of diabetes, obesity level, alcohol consumption, and high fasting glucose, even within normal range, were significantly associated with onset of prediabetes/diabetes in 5 years. The area under the receiver operating characteristic curve value was 0.68 with original and validated data, indicating that the risk assessment tool had reasonably good discrimination ability. Conclusions This new noninvasive screening tool, based on data from American Indian young adults, has potential to screen young adults’ early-onset diabetes risk. Future studies are warranted to test this risk assessment tool in other racial/ethnic young adults.

Background and Objective: A multitude of large cohort studies have collected data on incidence and covariates/risk factors of various chronic diseases. However, approaches for utilization of these large data and translation of the valuable results to inform and guide clinical disease prevention practice are not well developed. In this paper, we proposed, based on large cohort study data, a novel conceptual cost-effective disease prevention design strategy for a target group when it is not affordable to include everyone in the target group for intervention. Methods and Results: Data from American Indian participants (n = 3516; 2056 women) aged 45 - 74 years in the Strong Heart Study, the diabetes risk prediction model from the study, a utility function, and regression models were used. A conceptual cost-effective disease prevention design strategy based on large cohort data was initiated. The application of the proposed strategy for diabetes prevention was illustrated. Discussion: The strategy may provide reasonable solutions to address cost-effective prevention design issues. These issues include complex associations of a disease with its significant risk factors, cost-effectively selecting individuals at high risk of developing disease to undergo intervention, individual differences in health conditions, choosing intervention risk factors and setting their appropriate, attainable, gradual and adaptive goal levels for different subgroups, and assessing effectiveness of the prevention program. Conclusions: The strategy and methods shown in the illustrative example can also be analogously adopted and applied to other diseases preventions. The proposed strategy provides a way to translate and apply epidemiological study results to clinical disease prevention practice.

BackgroundIncreased serum levels of C-reactive protein (CRP), an important component of the innate immune response, are associated with increased risk of cardiovascular disease (CVD). Multiple single nucleotide polymorphisms (SNP) have been identified which are associated with CRP levels, and Mendelian randomization studies have shown a positive association between SNPs increasing CRP expression and risk of colon cancer (but thus far not CVD). The effects of individual genetic variants often interact with the genetic background of a population and hence we sought to resolve the genetic determinants of serum CRP in a number of American Indian populations.MethodsThe Strong Heart Family Study (SHFS) has serum CRP measurements from 2428 tribal members, recruited as large families from three regions of the United States. Microsatellite markers and MetaboChip defined SNP genotypes were incorporated into variance components, decomposition-based linkage and association analyses.ResultsCRP levels exhibited significant heritability (h2 = 0.33 ± 0.05, pConclusionIn agreement with evidence from other populations, these data show CRP serum levels are under considerable genetic influence; and include loci, such as near CRP and other genes, that replicate results from other ethnic groups. These findings also suggest possible novel loci on chr 6 and other chromosomes that warrant further investigation.

Non-caloric artificial sweeteners (NAS) are marketed as healthier alternatives to sugar, but the relationship between consumption of NAS and development of diabetes is unclear. This study assessed the associations of diet soda and NAS consumption with (1) early markers of insulin and glucose homeostasis (cross-sectionally) and (2) incident diabetes (over an average of 8 years of follow-up) among American Indians, a population with high rates of obesity.The study population included Strong Heart Family Study participants without cardiovascular disease or diabetes who participated in the 2007-2009 study exam (n = 1359). Diet soda and NAS consumption were assessed using a Block food frequency questionnaire and supplemental NAS questionnaire at the study exam. Fasting plasma glucose and insulin were measured during the study exam after a 12-h overnight fast. Participants were followed for incident diabetes through December 2017 using a single phone interview and medical record review; diabetes was identified by self-report and confirmed by documentation in medical records. Associations of diet soda and NAS consumption with fasting insulin, glucose, and incident diabetes were assessed using generalized estimating equations (fasting insulin and glucose analyses) and parametric survival models with Weibull distributions (incident diabetes analyses).Just under half of participants reported regularly consuming diet soda (40%) or using NAS to sweeten their beverages (41%). During an average 8 years of follow-up, we identified 98 cases of incident diabetes. After correction for multiple comparisons, there were no statistically significant associations of reported diet soda and NAS consumption with fasting insulin, fasting glucose, or incident diabetes.Although reported consumption of diet soda and NAS were high, neither were associated with diabetes risk.

Background and Objective: A multitude of large cohort studies have data on incidence rates and predictors of various chronic diseases. However, approaches for utilization of these costly collected data and translation of these valuable results to inform and guide clinical disease prevention practice are not well developed. In this paper we proposed a novel conceptual group/community disease prevention design strategy based on large cohort study data. Methods and Results: The data from participants (n = 3516; 2056 women) aged 45 to 74 years and the diabetes risk prediction model from Strong Heart Study were used. The Strong Heart Study is a population-based cohort study of cardiovascular disease and its risk factors in American Indians. A conceptual group/community disease prevention design strategy based on large cohort data was initiated. The application of the proposed strategy for group diabetes prevention was illustrated. Discussion: The strategy may provide reasonable solutions to the prevention design issues. These issues include complex associations of a disease with its combined and correlated risk factors, individual differences, choosing intervention risk factors and setting their appropriate, attainable, gradual and adaptive goal levels for different subgroups, and assessing effectiveness of the prevention program. Conclusions: The strategy and methods shown in the illustration example can be analogously adopted and applied for other diseases preventions. The proposed strategy for a target group/community in a population provides a way to translate and apply epidemiological study results to clinical disease prevention practice.

Background: Genetic research may inform underlying mechanisms for disparities in the burden of type 2 diabetes mellitus among American Indians. Our objective was to assess the association of genetic variants in cardiometabolic candidate genes with B cell dysfunction via HOMA-B, insulin resistance via HOMA-IR, and type 2 diabetes mellitus in the Strong Heart Family Study (SHFS).Methods and Results: We examined the association of variants, previously associated with cardiometabolic traits (∼200,000 from Illumina Cardio MetaboChip), using mixed models of HOMA-B residuals corrected for HOMA-IR (cHOMA-B), log transformed HOMA-IR, and incident diabetes, adjusted for age, sex, population stratification, and familial relatedness. Center-specific estimates were combined using fixed effect meta-analyses. We used Bonferroni correction to account for multiple testing (P < 4.13 × 10−7). We also assessed the association between variants in candidate diabetes genes with these metabolic traits. We explored the top SNPs in an independent, replication sample from Southwestern Arizona. We identified significant associations with cHOMA-B for common variants at 26 loci of which 8 were novel (PRSS7, FCRL5, PEL1, LRP12, IGLL1, ARHGEF10, PARVA, FLJ16686). The most significant variant association with cHOMA-B was observed on chromosome 5 for an intergenic variant near PARP8 (rs2961831, P = 6.39 × 10−9). In the replication study, we found a signal at rs4607517 near GCK/YKT6 (P = 0.01). Variants near candidate diabetes genes (especially GCK and KCNQ1) were also nominally associated with HOMA-IR and cHOMA-B.Conclusion: We identified variants at novel loci and confirmed those at known candidate diabetes loci associations for cHOMA-B. This study also provided evidence for association of variants at KCNQ2, CTNAA2, and KCNQ1with cHOMA-B among American Indians. Further studies are needed to account for the high heritability of diabetes among the American Indian participants of the SHFS cohort.

The Cerebrovascular Disease and Its Consequences in American Indians (CDCAI) Study recruited surviving members of a 20-year, longitudinal, population-based cohort of American Indians focused on cardiovascular disease, its risk factors, and its consequences. The goal of CDCAI Study is to characterize the burden, risk factors, and manifestations of vascular brain injury identified on cranial magnetic resonance imaging (MRI). CDCAI Study investigators enrolled 1,033 participants aged 60 years and older from 11 American Indian communities and tribes in the Northern Plains, Southern Plains, and Southwestern U.S. In addition to cranial MRI performed according to standardized protocols, participants underwent extensive medical interview, clinical examination, neurocognitive testing, physical function evaluation, electrocardiogram, and provided blood and urine specimens. Participants also self-administered questionnaires covering demographics, quality of life, and medical history. This report describes the design, implementation, and some of the unique challenges of this study and data collection.

High arsenic exposure has been related to diabetes, but at low-moderate levels the evidence is mixed. Arsenic metabolism, which is partly genetically controlled and may rely on certain B vitamins, plays a role in arsenic toxicity.We evaluated the prospective association of arsenic exposure and metabolism with type 2 diabetes and insulin resistance.We included 1,838 American Indian men and women free of diabetes (median age, 36 y). Arsenic exposure was assessed as the sum of inorganic arsenic (iAs), monomethylarsonate (MMA), and dimethylarsinate (DMA) urine concentrations (ΣAs). Arsenic metabolism was evaluated by the proportions of iAs, MMA, and DMA over their sum (iAs%, MMA%, and DMA%). Homeostasis model assessment for insulin resistance (HOMA2-IR) was measured at baseline and follow-up visits. Incident diabetes was evaluated at follow-up.Median ΣAs, iAs%, MMA%, and DMA% was 4.4 μg/g creatinine, 9.5%, 14.4%, and 75.6%, respectively. Over 10,327 person-years of follow-up, 252 participants developed diabetes. Median HOMA2-IR at baseline was 1.5. The fully adjusted hazard ratio [95% confidence interval (CI)] for incident diabetes per an interquartile range increase in ΣAs was 1.57 (95% CI: 1.18, 2.08) in participants without prediabetes at baseline. Arsenic metabolism was not associated with incident diabetes. ΣAs was positively associated with HOMA2-IR at baseline but negatively with HOMA2-IR at follow-up. Increased MMA% was associated with lower HOMA2-IR when either iAs% or DMA% decreased. The association of arsenic metabolism with HOMA2-IR differed by B-vitamin intake andAmong participants without baseline prediabetes, arsenic exposure was associated with incident diabetes. Low MMA% was cross-sectional and prospectively associated with higher HOMA2-IR. Research is needed to confirm possible interactions of arsenic metabolism with B vitamins and

OBJECTIVE To identify novel metabolic markers for diabetes development in American Indians. RESEARCH DESIGN AND METHODS Using an untargeted high-resolution liquid chromatography–mass spectrometry, we conducted metabolomics analysis of study participants who developed incident diabetes (n = 133) and those who did not (n = 298) from 2,117 normoglycemic American Indians followed for an average of 5.5 years in the Strong Heart Family Study. Relative abundances of metabolites were quantified in baseline fasting plasma of all 431 participants. Prospective association of each metabolite with risk of developing type 2 diabetes (T2D) was examined using logistic regression adjusting for established diabetes risk factors. RESULTS Seven metabolites (five known and two unknown) significantly predict the risk of T2D. Notably, one metabolite matching 2-hydroxybiphenyl was significantly associated with an increased risk of diabetes, whereas four metabolites matching PC (22:6/20:4), (3S)-7-hydroxy-2′,3′,4′,5′,8-pentamethoxyisoflavan, or tetrapeptides were significantly associated with decreased risk of diabetes. A multimarker score comprising all seven metabolites significantly improved risk prediction beyond established diabetes risk factors including BMI, fasting glucose, and insulin resistance. CONCLUSIONS The findings suggest that these newly detected metabolites may represent novel prognostic markers of T2D in American Indians, a group suffering from a disproportionately high rate of T2D.

The associations of pulmonary function with cardiovascular disease (CVD) independent of diabetes mellitus (DM) and metabolic syndrome have not been examined in a population-based setting. We examined prevalence and incidence CVD in relation to lower pulmonary function in the Strong Heart Study second examination (1993 to 1995) in 352 CVD and 2,873 non-CVD adults free of overt lung disease (mean age 60 years). Lung function was assessed by standard spirometry. Participants with metabolic syndrome or DM with or without CVD had lower pulmonary function than participants without these conditions after adjustment for hypertension, age, gender, abdominal obesity, smoking, physical activity index, and study field center. CVD participants with DM had significantly lower forced vital capacity than participants with CVD alone. Significant associations were observed between reduced pulmonary function, preclinical CVD, and prevalent CVD after adjustment for multiple CVD risk factors. During follow-up (median 13.3 years), pulmonary function did not predict CVD incidence, it predicted CVD mortality. Among 3,225 participants, 412 (298 without baseline CVD) died from CVD by the end of 2008. In models adjusted for multiple CVD risk factors, DM, metabolic syndrome, and baseline CVD, compared with highest quartile of lung function, lower lung function predicted CVD mortality (relative risk up to 1.5, 95% confidence interval 1.1 to 2.0, p0.05). In conclusion, a population with a high prevalence of DM and metabolic syndrome and lower lung function was independently associated with prevalent clinical and preclinical CVD, and its impairment predicted CVD mortality. Additional research is needed to identify mechanisms linking metabolic abnormalities, low lung function, and CVD.

Short leukocyte telomere length (LTL) has been associated with atherosclerosis in cross-sectional studies, but the prospective relationship between telomere shortening and risk of developing carotid atherosclerosis has not been well-established. This study examines whether LTL at baseline predicts incidence and progression of carotid atherosclerosis in American Indians in the Strong Heart Study. The analysis included 2,819 participants who were free of overt cardiovascular disease at baseline (2001-2003) and were followed through the end of 2006-2009 (average 5.5-yr follow-up). Discrete atherosclerotic plaque was defined as focal protrusion with an arterial wall thickness ≥50% the surrounding wall. Carotid progression was defined as having a higher plaque score at the end of study follow-up compared to baseline. Associations of LTL with incidence and progression of carotid plaque were examined using Cox proportional hazard regression, adjusting for standard coronary risk factors. Compared to participants in the highest LTL tertile, those in the lowest tertile had significantly elevated risk for both incident plaque (HR, 1.49; 95% CI, 1.09-2.03) and plaque progression (HR, 1.61; 95% CI, 1.26-2.07). Our results provide initial evidence for a potential prognostic utility of LTL in risk prediction for atherosclerosis.

Background Cigarette smoking negatively affects kidney function. Genetic variants in the nicotinic acetylcholine receptor (nAChR) genes have been associated with nicotine dependence, and are likely to influence renal function and related traits. Whereas each single variant may only exert a small effect, the joint contribution of multiple variants to the risk of disease could be substantial. Methods Using a gene-family approach, we investigated the joint association of 61 tagging SNPs in seven genes encoding the nAChRs with kidney function in 3620 American Indians participating in the Strong Heart Family Study, independent of known risk factors. Kidney function was evaluated by estimated glomerular filtration rate, urinary albumin/creatinine ratio, albuminuria and chronic kidney disease. The joint impact of smoking-related variants was assessed using the weighted truncated product method. Results Multiple SNPs showed marginal individual effect on renal function variability, and only a few survive multiple comparison correction. In contrast, a gene-family analysis considering the joint impact of all 61 SNPs reveals significant associations of the nAChR gene family with kidney function variables including estimated glomerular filtration rate, urinary albumin/creatinine ratio, and albuminuria (all Ps ≤ 0.0001) after adjusting for established risk factors including cigarette smoking. Conclusion Genetic variants in nAChR genes jointly contribute to renal function or kidney damage in American Indians. The effects of these genetic variants on kidney function or damage are independent of traditional risk factors including cigarette smoking per se.

Short telomere length, a marker of biological aging, has been associated with age-related metabolic disorders. Telomere attrition induces profound metabolic dysfunction in animal models, but no study has examined the metabolome of telomeric aging in human. Here we studied 423 apparently healthy American Indians participating in the Strong Family Heart Study. Leukocyte telomere length (LTL) was measured by qPCR. Metabolites in fasting plasma were detected by untargeted LC/MS. Associations of LTL with each metabolite and their combined effects were examined using generalized estimating equation adjusting for chronological age and other aging-related factors. Multiple testing was corrected using the q-value method (q

Abstarct Objective Gene × diet interaction plays an important role in atherosclerosis, an inflammatory disorder. Leukotrienes are the most potent inflammatory mediators, and genetic variants encoding leukotriene genes have been implicated in atherosclerosis. This study tests nutrigenetic interaction of a previously defined leukotriene haplotype on carotid artery hypertrophy and atherosclerosis in American Indians. Methods This study included 3402 American Indians participating in the Strong Heart Family Study (SHFS). Carotid artery measurements, including intima-media thickness (IMT), vascular mass, and plaque, were assessed using ultrasound. Eleven tagSNPs in the leukotriene A4 hydrolase ( LTA4H ) gene were genotyped in all subjects. Main haplotype effect and haplotype × diet interaction were examined by generalized estimating equation, adjusting for known risk factors. Results There was no significant main effect of haplotype or diet on any of the carotid artery measures. However, a previously defined LTA4H haplotype, called HapE, significantly interacted with dietary intake of n-3 and n-6 fatty acids on both IMT ( P HapE×n3 = 0.018, P HapE×n6 = 0.040) and vascular mass ( P HapE×n3 = 0.012, P HapE×n6 = 0.018), but not plaque. The direction of this nutrigenetic interaction on IMT was consistent with that reported in a recent study of Caucasian twins. Conclusion Dietary intake of polyunsaturated fatty acids significantly modifies the effect of a leukotriene haplotype on carotid artery hypertrophy but not atherosclerosis in American Indians, independent of established cardiovascular risk factors. Replication of nutrigenetic interaction in two distinct ethnic groups suggests the robustness and generalizability of our findings to diverse populations.

An estimation of myocardial mechano-energetic efficiency (MEE) per unit of left ventricular (LV) mass (MEEi) can significantly predict composite cardiovascular (CV) events in treated hypertensive patients with normal ejection fraction (EF), after adjustment for LV hypertrophy (LVH). We have tested whether MEEi predicts incident heart failure (HF), after adjustment for LVH, in the population-based cohort of a “Strong Heart Study” (SHS) with normal EF. We included 1912 SHS participants (age 59 ± 8 years; 64% women) with preserved EF (≥50%) and without prevalent CV disease. MEE was estimated as the ratio of stroke work to the “double product” of heart rate times systolic blood pressure. MEEi was calculated as MEE/LV mass, and analyzed in quartiles. During a follow-up study of 9.2 ± 2.3 years, 126 participants developed HF (7%). HF was preceded by acute myocardial infarction (AMI) in 94 participants. A Kaplan-Meier plot, in quartiles of MEEi, demonstrated significant differences, substantially due to the deviation of the lowest quartile (p < 0.0001). Using AMI as a competing risk event, sequential models of Cox regression for incident HF (including significant confounders), demonstrated that low MEEi predicted incident HF not due to AMI (p = 0.026), after adjustment for significant effect of age, LVH, prolonged LV relaxation, diabetes, and smoking habits with negligible effects for sex, hypertension, antihypertensive therapy, obesity, and hyperlipemia. Low LV mechano-energetic efficiency per unit of LVM, is a predictor of incident, non-AMI related, HF in subjects with initially normal EF.

Summary Background and objectives CKD disproportionally affects American Indians, who similar to other populations, show genetic susceptibility to kidney outcomes. Recent studies have identified several loci associated with kidney traits, but their relevance in American Indians is unknown. Design, setting, participants, & measurements This study used data from a large, family-based genetic study of American Indians (the Strong Heart Family Study), which includes 94 multigenerational families enrolled from communities located in Oklahoma, the Dakotas, and Arizona. Individuals were recruited from the Strong Heart Study, a population-based study of cardiovascular disease in American Indians. This study selected 25 single nucleotide polymorphisms in 23 loci identified from recently published kidney-related genome-wide association studies in individuals of European ancestry to evaluate their associations with kidney function (estimated GFR; individuals 18 years or older, up to 3282 individuals) and albuminuria (urinary albumin to creatinine ratio; n=3552) in the Strong Heart Family Study. This study also examined the association of single nucleotide polymorphisms in the APOL1 region with estimated GFR in 1121 Strong Heart Family Study participants. GFR was estimated using the abbreviated Modification of Diet in Renal Disease Equation. Additive genetic models adjusted for age and sex were used. Results This study identified significant associations of single nucleotide polymorphisms with estimated GFR in or nearby PRKAG2, SLC6A13, UBE2Q2, PIP5K1B ,a ndWDR72 (P,2.1 3 10 -3 to account for multiple testing). Single nucleotide polymorphisms in these loci explained 2.2% of the estimated GFR total variance and 2.9% of its heritability. An intronic variant of BCAS3 was significantly associated with urinary albumin to creatinine ratio. APOL1 single nucleotide polymorphisms were not associated with estimated GFR in a single variant test or haplotype analyses, and the at-risk variants identified in individuals with African ancestry were not detected in DNA sequencing of American Indians. Conclusion This study extends the genetic associations of loci affecting kidney function to American Indians, a population at high risk of kidney disease, and provides additional support for a potential biologic relevance of these loci across ancestries. Clin J Am Soc Nephrol 9: 150–158, 2014. doi: 10.2215/CJN.02300213

Telomeres play a central role in cellular aging, and shorter telomere length has been associated with age-related disorders including diabetes. However, a causal link between telomere shortening and diabetes risk has not been established. In a well-characterized longitudinal cohort of American Indians participating in the Strong Heart Family Study, we examined whether leukocyte telomere length (LTL) at baseline predicts incident diabetes independent of known diabetes risk factors. Among 2,328 participants free of diabetes at baseline, 292 subjects developed diabetes during an average 5.5 years of follow-up. Compared with subjects in the highest quartile (longest) of LTL, those in the lowest quartile (shortest) had an almost twofold increased risk of incident diabetes (hazard ratio [HR] 1.83 [95% CI 1.26–2.66]), whereas the risk for those in the second (HR 0.87 [95% CI 0.59–1.29]) and the third (HR 0.95 [95% CI 0.65–1.38]) quartiles was statistically nonsignificant. These findings suggest a nonlinear association between LTL and incident diabetes and indicate that LTL could serve as a predictive marker for diabetes development in American Indians, who suffer from disproportionately high rates of diabetes.