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Introduction: Racial and ethnic minority groups and individuals with limited educational attainment experience a disproportionate burden of diabetes. Prediabetes represents a high-risk state for developing type 2 diabetes, but most adults with prediabetes are unaware of having the condition. Uncovering whether racial, ethnic, or educational disparities also occur in the prediabetes stage could help inform strategies to support health equity in preventing type 2 diabetes and its complications. We examined the prevalence of prediabetes and prediabetes awareness, with corresponding prevalence ratios according to race, ethnicity, and educational attainment., Methods: This study was a pooled cross-sectional analysis of the National Health and Nutrition Examination Survey data from 2011 to March 2020. The final sample comprised 10,262 U.S. adults who self-reported being Asian, Black, Hispanic, or White. Prediabetes was defined using hemoglobin A1c and fasting plasma glucose values. Those with prediabetes were classified as "aware" or "unaware" based on survey responses. We calculated prevalence ratios (PR) to assess the relationship between race, ethnicity, and educational attainment with prediabetes and prediabetes awareness, controlling for sociodemographic, health and healthcare-related, and clinical characteristics., Results: In fully adjusted logistic regression models, Asian, Black, and Hispanic adults had a statistically significant higher risk of prediabetes than White adults (PR:1.26 [1.18,1.35], PR:1.17 [1.08,1.25], and PR:1.10 [1.02,1.19], respectively). Adults completing less than high school and high school had a significantly higher risk of prediabetes compared to those with a college degree (PR:1.14 [1.02,1.26] and PR:1.12 [1.01,1.23], respectively). We also found that Black and Hispanic adults had higher rates of prediabetes awareness in the fully adjusted model than White adults (PR:1.27 [1.07,1.50] and PR:1.33 [1.02,1.72], respectively). The rates of prediabetes awareness were consistently lower among those with less than a high school education relative to individuals who completed college (fully-adjusted model PR:0.66 [0.47,0.92])., Discussion: Disparities in prediabetes among racial and ethnic minority groups and adults with low educational attainment suggest challenges and opportunities for promoting health equity in high-risk groups and expanding awareness of prediabetes in the United States., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Formagini, Brooks, Roberts, Bullard, Zhang, Saelee and O’Brien.)

Objective: Race and ethnicity data disaggregated into detailed subgroups may reveal pronounced heterogeneity in diabetes risk factors. We therefore used disaggregated data to examine the prevalence of type 2 diabetes risk factors related to lifestyle behaviors and barriers to preventive care among adults in the U.S., Research Design and Methods: We conducted a pooled cross-sectional study of 3,437,640 adults aged ≥18 years in the U.S. without diagnosed diabetes from the Behavioral Risk Factor Surveillance System (2013-2021). For self-reported race and ethnicity, the following categories were included: Hispanic (Cuban, Mexican, Puerto Rican, Other Hispanic), non-Hispanic (NH) American Indian/Alaska Native, NH Asian (Chinese, Filipino, Indian, Japanese, Korean, Vietnamese, Other Asian), NH Black, NH Pacific Islander (Guamanian/Chamorro, Native Hawaiian, Samoan, Other Pacific Islander), NH White, NH Multiracial, NH Other. Risk factors included current smoking, hypertension, overweight or obesity, physical inactivity, being uninsured, not having a primary care doctor, health care cost concerns, and no physical exam in the past 12 months., Results: Prevalence of hypertension, lifestyle factors, and barriers to preventive care showed substantial heterogeneity among both aggregated, self-identified racial and ethnic groups and disaggregated subgroups. For example, the prevalence of overweight or obesity ranged from 50.8% (95% CI 49.1-52.5) among Chinese adults to 79.8% (73.5-84.9) among Samoan adults. Prevalence of being uninsured among Hispanic subgroups ranged from 11.4% (10.9-11.9) among Puerto Rican adults to 33.0% (32.5-33.5) among Mexican adults., Conclusions: These findings underscore the importance of using disaggregated race and ethnicity data to accurately characterize disparities in type 2 diabetes risk factors and access to care., (© 2023 by the American Diabetes Association.)

We examined the prevalence of diagnosed depression, anxiety, and ADHD among youth by diabetes type, insurance type, and race/ethnicity. These mental disorders were more prevalent among youth with diabetes, particularly those with type 2 diabetes, with non-Hispanic White youth with Medicaid and diabetes having a higher prevalence than other races/ethnicities., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Aims: The overall prevalence of diabetes has increased over the past two decades in the United States, disproportionately affecting low-income populations. We aimed to examine the trends in income-related inequalities in diabetes prevalence and to identify the contributions of determining factors., Methods: We estimated income-related inequalities in diagnosed diabetes during 2001-2018 among US adults aged 18 years or older using data from the National Health Interview Survey (NHIS). The concentration index was used to measure income-related inequalities in diabetes and was decomposed into contributing factors. We then examined temporal changes in diabetes inequality and contributors to those changes over time., Results: Results showed that income-related inequalities in diabetes, unfavorable to low-income groups, persisted throughout the study period. The income-related inequalities in diabetes decreased during 2001-2011 and then increased during 2011-2018. Decomposition analysis revealed that income, obesity, physical activity levels, and race/ethnicity were important contributors to inequalities in diabetes at almost all time points. Moreover, changes regarding age and income were identified as the main factors explaining changes in diabetes inequalities over time., Conclusions: Diabetes was more prevalent in low-income populations. Our study contributes to understanding income-related diabetes inequalities and could help facilitate program development to prevent type 2 diabetes and address modifiable factors to reduce diabetes inequalities., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

Importance: Improvements in control of factors associated with diabetes risk in the US have stalled and remain suboptimal. The benefit of continually improving goal achievement has not been evaluated to date., Objective: To quantify potential gains in life expectancy (LE) among people with type 2 diabetes (T2D) associated with lowering glycated hemoglobin (HbA1c), systolic blood pressure (SBP), low-density lipoprotein cholesterol (LDL-C), and body mass index (BMI) toward optimal levels., Design, Setting, and Participants: In this decision analytical model, the Building, Relating, Assessing, and Validating Outcomes (BRAVO) diabetes microsimulation model was calibrated to a nationally representative sample of adults with T2D from the National Health and Nutrition Examination Survey (2015-2016) using their linked short-term mortality data from the National Death Index. The model was then used to conduct the simulation experiment on the study population over a lifetime. Data were analyzed from January to October 2021., Exposure: The study population was grouped into quartiles on the basis of levels of HbA1c, SBP, LDL-C, and BMI. LE gains associated with achieving better control were estimated by moving people with T2D from the current quartile of each biomarker to the lower quartiles., Main Outcomes and Measures: Life expectancy., Results: Among 421 individuals, 194 (46%) were women, and the mean (SD) age was 65.6 (8.9) years. Compared with a BMI of 41.4 (mean of the fourth quartile), lower BMIs of 24.3 (first), 28.6 (second), and 33.0 (third) were associated with 3.9, 2.9, and 2.0 additional life-years, respectively, in people with T2D. Compared with an SBP of 160.4 mm Hg (fourth), lower SBP levels of 114.1 mm Hg (first), 128.2 mm Hg (second), and 139.1 mm Hg (third) were associated with 1.9, 1.5, and 1.1 years gained in LE in people with T2D, respectively. A lower LDL-C level of 59 mg/dL (first), 84.0 mg/dL (second), and 107.0 mg/dL (third) were associated with 0.9, 0.7, and 0.5 years gain in LE, compared with LDL-C of 146.2 mg/dL (fourth). Reducing HbA1c from 9.9% (fourth) to 7.7% (third) was associated with 3.4 years gain in LE. However, a further reduction to 6.8% (second) was associated with only a mean of 0.5 years gain in LE, and from 6.8% to 5.9% (first) was not associated with LE benefit. Overall, reducing HbA1c from the fourth quartile to the first is associated with an LE gain of 3.8 years., Conclusions and Relevance: These findings can be used by clinicians to motivate patients in achieving the recommended treatment goals and to help prioritize interventions and programs to improve diabetes care in the US.

Low socioeconomic position (SEP) across the lifecourse is associated with Type 2 diabetes (T2DM). We examined whether these economic disparities differ by race and sex. We included 5448 African American (AA) and white participants aged ≥45 years from the national (United States) REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort without T2DM at baseline (2003-07). Incident T2DM was defined by fasting glucose ≥126 mg/dL, random glucose ≥200 mg/dL, or using T2DM medications at follow-up (2013-16). Derived SEP scores in childhood (CSEP) and adulthood (ASEP) were used to calculate a cumulative (CumSEP) score. Social mobility was defined as change in SEP. We fitted race-stratified logistic regression models to estimate the association between each lifecourse SEP indicator and T2DM, adjusting for covariates; additionally, we tested SEP-sex interactions. Over a median of 9.0 (range 7-14) years of follow-up, T2DM incidence was 167.1 per 1000 persons among AA and 89.9 per 1000 persons among white participants. Low CSEP was associated with T2DM incidence among AA (OR = 1.61; 95%CI 1.05-2.46) but not white (1.06; 0.74-2.33) participants; this was attenuated after adjustment for ASEP. In contrast, low CumSEP was associated with T2DM incidence for both racial groups. T2DM risk was similar for stable low SEP and increased for downward mobility when compared with stable high SEP in both groups, whereas upward mobility increased T2DM risk among AAs only. No differences by sex were observed. Among AAs, low CSEP was not independently associated with T2DM, but CSEP may shape later-life experiences and health risks., (Copyright © 2021 Elsevier Inc. All rights reserved.)

People with type 2 diabetes often experience two common mental health conditions: depression and diabetes distress. Both increase a patient's risk for mortality, poor disease management, diabetes-related complications, and poor quality of life. The American Diabetes Association and the U.S. Preventive Services Task Force recommend routine evaluations for these conditions in adults for optimal disease management and prevention of life-threatening complications. However, barriers exist within primary care and specialty settings that make screening for depression and diabetes distress challenging. Depression and diabetes distress influence diabetes self-care and diabetes control and barriers in clinical care practice that can hinder detection and management of psychosocial issues in diabetes care. This paper highlights opportunities to increase mental health screenings and provides strategies to help providers address depression and diabetes distress in patients with type 2 diabetes.

Diabetes during pregnancy increases the risk for adverse maternal and infant health outcomes. Type 1 or type 2 diabetes diagnosed before pregnancy (preexisting diabetes) increases infants' risk for congenital anomalies, stillbirth, and being large for gestational age (1). Diabetes that develops and is diagnosed during the second half of pregnancy (gestational diabetes) increases infants' risk for being large for gestational age (1) and might increase the risk for childhood obesity (2); for mothers, gestational diabetes increases the risk for future type 2 diabetes (3). In the United States, prevalence of both preexisting and gestational diabetes increased from 2000 to 2010 (4,5). Recent state-specific trends have not been reported; therefore, CDC analyzed 2012-2016 National Vital Statistics System (NVSS) birth data. In 2016, the crude national prevalence of preexisting diabetes among women with live births was 0.9%, and prevalence of gestational diabetes was 6.0%. Among 40 jurisdictions with continuously available data from 2012 through 2016, the age- and race/ethnicity-standardized prevalence of preexisting diabetes was stable at 0.8% and increased slightly from 5.2% to 5.6% for gestational diabetes. Preconception care and lifestyle interventions before, during, and after pregnancy might provide opportunities to control, prevent, or mitigate health risks associated with diabetes during pregnancy., Competing Interests: All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Accurately quantifying undiagnosed type 2 diabetes is an important challenge for conducting diabetes surveillance and identifying the potential missed opportunities for preventing complications. However, there has been little focused attention on how undiagnosed diabetes is defined in epidemiologic surveys and how limitations in methods used to ascertain undiagnosed diabetes may impact our understanding of the magnitude of this important public health problem. This Perspective highlights weaknesses in how undiagnosed diabetes is quantified in epidemiologic research and the biases and caveats that should be considered when using estimates of undiagnosed diabetes to influence public health policy., (© 2018 by the American Diabetes Association.)

Objective: We examined the proportion of American adults without type 2 diabetes that engages in lifestyle behaviors known to reduce type 2 diabetes risk., Research Design and Methods: We conducted a cross-sectional analysis of 3,679 nonpregnant, nonlactating individuals aged ≥20 years without diabetes (self-reported diagnosis or glycated hemoglobin ≥6.5% [8 mmol/mol] or fasting plasma glucose ≥126 mg/dL) and who provided 2 days of reliable dietary data in the 2007-2012 National Health and Nutrition Examination Surveys (NHANES). We used the average of 2 days of dietary recall and self-reported leisure-time physical activity to assess whether participants met type 2 diabetes risk reduction goals (meeting four or more MyPlate recommendations [adequate consumption of fruits, vegetables, dairy, grains, meat, beans, and eggs]; not exceeding three maximum allowances for alcoholic beverages, added sugars, fat, and cholesterol; and meeting physical activity recommendations [≥150 min/week])., Results: Approximately 21%, 29%, and 13% of individuals met fruit, vegetable, and dairy goals, respectively. Half (51.6%) met the goal for total grains, compared with 18% for whole grains, and 54.2% met the meat/beans goal and 40.6% met the oils goal. About one-third (37.8%) met the physical activity goal, and 58.6% met the weight loss/maintenance goal. Overall, 3.1% (95% CI 2.4-4.0) of individuals met the majority of type 2 diabetes risk reduction goals. Younger age and lower educational attainment were associated with lower probability of meeting goals., Conclusions: A small proportion of U.S. adults engages in risk reduction behaviors. Research and interventions targeted at young and less-educated segments of the population may help close gaps in risk reduction behaviors., (© 2018 by the American Diabetes Association.)

Currently 23 million U.S. adults have been diagnosed with diabetes (1). The two most common forms of diabetes are type 1 and type 2. Type 1 diabetes results from the autoimmune destruction of the pancreas's beta cells, which produce insulin. Persons with type 1 diabetes require insulin for survival; insulin may be given as a daily shot or continuously with an insulin pump (2). Type 2 diabetes is mainly caused by a combination of insulin resistance and relative insulin deficiency (3). A small proportion of diabetes cases might be types other than type 1 or type 2, such as maturity-onset diabetes of the young or latent autoimmune diabetes in adults (3). Although the majority of prevalent cases of type 1 and type 2 diabetes are in adults, national data on the prevalence of type 1 and type 2 in the U.S. adult population are sparse, in part because of the previous difficulty in classifying diabetes by type in surveys (2,4,5). In 2016, supplemental questions to help distinguish diabetes type were added to the National Health Interview Survey (NHIS) (6). This study used NHIS data from 2016 to estimate the prevalence of diagnosed diabetes among adults by primary type. Overall, based on self-reported type and current insulin use, 0.55% of U.S. adults had diagnosed type 1 diabetes, representing 1.3 million adults; 8.6% had diagnosed type 2 diabetes, representing 21.0 million adults. Of all diagnosed cases, 5.8% were type 1 diabetes, and 90.9% were type 2 diabetes; the remaining 3.3% of cases were other types of diabetes. Understanding the prevalence of diagnosed diabetes by type is important for monitoring trends, planning public health responses, assessing the burden of disease for education and management programs, and prioritizing national plans for future type-specific health services., Competing Interests: No conflicts of interest were reported.

Objective: Relationships were examined between persistent organic pollutants (POPs) and incident type 2 diabetes, end-stage renal disease (ESRD) and mortality., Methods: In a nested case-control study, 300 persons without diabetes had baseline examinations between 1969 and 1974; 149 developed diabetes (cases) and 151 remained non-diabetic (controls) during 8.0 and 23.1 years of follow-up, respectively. POPs were measured at baseline. ORs for diabetes were computed by logistic regression analysis. The cases were followed from diabetes onset to ESRD, death or 2013. HRs for ESRD and mortality were computed by cause-specific hazard models. Patterns of association were explored using principal components analysis., Results: PCB151 increased the odds for incident diabetes, whereas hexachlorobenzene (HCB) was protective after adjusting for age, sex, body mass index, sample storage characteristics, glucose and lipid levels. Associations between incident diabetes and polychlorinatedbiphenyl (PCB) or persistent pesticide (PST) components were mostly positive but non-significant. Among the cases, 29 developed ESRD and 48 died without ESRD. PCB28, PCB49 and PCB44 increased the risk of ESRD after adjusting for baseline demographic and clinical characteristics. Several PCBs and PSTs increased the risk of death without ESRD. The principal components analysis identified PCBs with low-chlorine load positively associated with ESRD and death without ESRD, and several PSTs associated with death without ESRD., Conclusions: Most POPs were positively but not significantly associated with incident diabetes. PCB151 was significantly predictive and HCB was significantly protective for diabetes. Among participants with diabetes, low-chlorine PCBs increase the risk of ESRD and death without ESRD, whereas several PSTs predict death without ESRD., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: In 2010, the American Diabetes Association (ADA) endorsed hemoglobin A1c (HbA1c) as 1 of 3 tests for diabetes and prediabetes screening. We describe the use of HbA1c testing for screening during routine visits in primary care clinics of an urban health care system in the U.S., Methods: In 2013 to 2014, retrospective analyses of deidentified electronic health records over a 2-year period, January 2010 to December 2011, for academic private practices (clinic group 1) and federally-qualified Community Health Centers (clinic group 2) identified 11,885 adults without prior diabetes or recent HbA1c testing. We estimated the proportion of patients eligible for screening according to ADA and U.S. Preventative Services Task Force (USPSTF) guidelines and calculated the potential yield of previously undiagnosed diabetes or prediabetes among those who received at least 1 HbA1c test., Results: Overall, 3,316 and 5,613 patients of clinic groups 1 and 2 (75.2% of each) were eligible for screening by ADA guidelines, while only 1,764 (39.9%) of clinic group 1 and 3,799 (50.9%) of clinic group 2 were eligible by USPSTF guidelines. In those eligible by either guideline, 731 (21.4%) patients of clinic group 1 and 1,293 (21.5%) of clinic group 2 received HbA1c testing; among these, in 71 (9.7%) and 121 (9.4%) patients from clinic groups 1 and 2, respectively, HbA1c results were in the diabetes range, and in 330 (45.2%) and 733 (56.7%), results were in the prediabetes range., Conclusion: In urban primary care settings, appropriate HbA1c testing could result in the detection of a substantial number of previously undiagnosed diabetes and prediabetes cases needing treatment.

Objective: To examine the relationship between access to health care and diabetes control., Research Design and Methods: Using data from the National Health and Nutrition Examination Survey, 1999-2008, we identified 1,221 U.S. adults (age 18-64 years) with self-reported diabetes. Access was measured by current health insurance coverage, number of times health care was received over the past year, and routine place to go for health care. Diabetes control measures included the proportion of people with A1C >9%, blood pressure ≥140/90 mmHg, and non-HDL cholesterol ≥130 mg/dL., Results: An estimated 16.0% of known diabetic adults were uninsured. Diabetes control profiles were worse among uninsured than among insured persons (A1C >9% [34.1 vs. 16.5%, P = 0.002], blood pressure ≥140/90 mmHg [31.8 vs. 22.8%, P < 0.05], and non-HDL cholesterol ≥130 mg/dL [67.1 vs. 65.4%, P = 0.7]). Compared with insured persons, uninsured persons were more likely to have A1C >9% (multivariate-adjusted odds ratio 2.4 [95% CI 1.2-4.7]). Compared with those who reported four or more health care visits in the past year, those who reported no health care visits were more likely to have A1C >9% (5.5 [1.2-26.3]) and blood pressure ≥140/90 mmHg (1.9 [1.1-3.4])., Conclusions: In people with diabetes, lack of health care coverage is associated with poor glycemic control. In addition, low use of health care service is associated with poor glucose and blood pressure control.

Background: New recommendations about the use of hemoglobin A1c (HbA1c) for diagnosing diabetes have stimulated a debate about the optimal HbA1c cutoff to identify prediabetes for preventive intervention., Purpose: To assess the cost effectiveness associated with the alternative HbA1c cutoffs for identifying prediabetes., Methods: A Markov simulation model was used to examine the cost effectiveness associated with a progressive 0.1% decrease in the HbA1c cutoff from 6.4% to 5.5%. The target population was the U.S. nondiabetic population aged ≥18 years. The simulation sample was created using the data of nondiabetic American adults from the National Health and Nutritional Examination Survey (NHANES 1999-2006). People identified as having prediabetes were assumed to receive a preventive intervention, with effectiveness the same as that in the Diabetes Prevention Program study under a high-cost intervention (HCI) scenario and in the Promoting a Lifestyle of Activity and Nutrition for Working to Alter the Risk of Diabetes study under a low-cost intervention (LCI) scenario. The analysis was conducted for a lifetime horizon from a healthcare system perspective., Results: Lowering the HbA1c cutoff would increase the health benefits of the preventive interventions at higher costs. For the HCI, lowering the HbA1c cutoff from 6.0% to 5.9% and from 5.9% to 5.8% would result in $27,000 and $34,000 per QALY gained, respectively. Continuing to decrease the cutoff from 5.8% to 5.7%, from 5.7% to 5.6%, and from 5.6% to 5.5% would cost $45,000, $58,000, and $96,000 per QALY gained, respectively. For the LCI, lowering the HbA1c cutoff from 6.0% to 5.9% and from 5.9% to 5.8% would result in $24,000 and $27,000 per QALY gained, respectively. Continuing to lower the cutoff from 5.8% to 5.7%, 5.7% to 5.6%, and 5.6% to 5.5% would cost $34,000, $43,000 and $70,000 per QALY gained, respectively., Conclusions: Lowering the HbA1c cutoff for prediabetes leads to less cost-effective preventive interventions. Assuming a conventional $50,000/QALY cost-effectiveness benchmark, the HbA1c cutoffs of 5.7% and higher were found to be cost effective. Lowering the cutoff from 5.7% to 5.6% also may be cost effective, however, if the costs of preventive interventions were to be lowered., (Published by Elsevier Inc.)

Objective: To examine the relationship between access to health care and undiagnosed diabetes among the high-risk, vulnerable population in the border region between the United States of America and Mexico., Methods: Using survey and fasting plasma glucose data from Phase I of the U.S.-Mexico Border Diabetes Prevention and Control Project (February 2001 to October 2002), this epidemiological study identified 178 adults 18-64 years old with undiagnosed diabetes, 326 with diagnosed diabetes, and 2 966 without diabetes. Access to health care among that sample (n = 3,470), was assessed by type of health insurance coverage (including "none"), number of health care visits over the past year, routine pattern of health care utilization, and country of residence., Results: People with diabetes who had no insurance and no place to go for routine health care were more likely to be undiagnosed than those with insurance and a place for routine health care (odds ratio [OR] 2.6, 95% confidence interval [CI] 1.0-6.6, and OR 4.5, 95% CI 1.4-14.1, respectively). When stratified by country, the survey data showed that on the U.S. side of the border there were more people with undiagnosed diabetes if they were 1) uninsured versus the insured (28.9%, 95% CI 11.5%-46.3%, versus 9.1%, 95% CI 1.5%-16.7%, respectively) and if they 2) had made no visits or 1-3 visits to a health care facility in the past year versus had made ≥ 4 visits (40.8%, 95% CI 19.6%-62.0%, and 23.4%, 95% CI 9.9%-36.9%, respectively, versus 2.4%, 95% CI -0.9%-5.7%) (all, P < 0.05). No similar pattern was found in Mexico., Conclusions: Limited access to health care--especially not having health insurance and/or not having a place to receive routine health services--was significantly associated with undiagnosed diabetes in the U.S.-Mexico border region.

We examined ranges of A1C useful for identifying persons at high risk for diabetes prior to preventive intervention by conducting a systematic review. From 16 included studies, we found that annualized diabetes incidence ranged from 0.1% at A1C <5.0% to 54.1% at A1C >or=6.1%. Findings from 7 studies that examined incident diabetes across a broad range of A1C categories showed 1) risk of incident diabetes increased steeply with A1C across the range of 5.0 to 6.5%; 2) the A1C range of 6.0 to 6.5% was associated with a highly increased risk of incident diabetes, 25 to 50% incidence over 5 years; 3) the A1C range of 5.5 to 6.0% was associated with a moderately increased relative risk, 9 to 25% incidence over 5 years; and 4) the A1C range of 5.0 to 5.5% was associated with an increased incidence relative to those with A1C <5%, but the absolute incidence of diabetes was less than 9% over 5 years. Our systematic review demonstrated that A1C values between 5.5 and 6.5% were associated with a substantially increased risk for developing diabetes.