Search

Ferronickel slag is a by-product in the production of Ni–Fe alloy, which can be used to produce mineral wool. The crystallization and viscosity of ferronickel slag have great influence on the production process of mineral wool. The crystallization properties and viscosity of three kinds of ferronickel slags with different Al2O3 contents were investigated. It was studied by viscometer and high-temperature confocal scanning laser microscope (CSLM). The morphology and composition of crystals in the slag were characterized by field scanning electron microscope (FE-SEM) and energy dispersive spectrometer (EDS). The experimental results show that the crystallization process of molten slag conforms to the Johnson-Mehl-Avrami (JMA) crystallization kinetic model. With the increase of Al2O3 content, the crystal size of ferronickel slag becomes smaller, the crystallization time increases, and the crystallization capacity decreases. The main crystallization product of No.1 and 2 slag is orthopyroxene, and the main crystallization product in No.3 slag is alumina. With the increase of Al2O3 content, the transition temperature of ferronickel slag increases first and then decreases. The variation of viscosity is mainly related to the precipitation and growth of crystals, and is also affected by the type and the number of crystals.

In order to explore the manufacturing process of mineral wool, the effects of isothermal temperature and cooling rate on the crystallization properties of silicomanganese slag were in-situ observed by using a confocal laser scanning microscopy (CLSM). In addition, the relationship between different cooling rates and the viscosity of silicomanganese slag was studied by a viscometer. The results show that the crystallinity of silicomanganese slag increases with the decrease of temperature in the range of 1325–1225 °C. At the same time, with the decrease of temperature, the crystallization mechanism of silicomanganese slag changes from two-dimensional to one-dimensional. Once the cooling rate is greater than 5 °C/s, the silicomanganese slag is glassy and will not precipitate crystals. The SEM images of the precipitated phase morphology of silicomanganese slag are consistent with the in-situ observation results of CLSM experiment, and the isothermal crystalline phase is anorthite. Moreover, the viscosity test shows that with the increase of cooling rate, the viscosity of silicomanganese slag decreases obviously at 1400 °C.

Purpose The purpose of the study was to examine how gender was related to enrollment and number of sessions attended in the National Diabetes Prevention Program’s Lifestyle Change Program (DPP LCP). Methods To better understand program uptake, a population of those who would be eligible for the LCP was compared to those who enrolled. Estimates of those eligible were computed using data from the National Health and Nutrition Examination Survey, whereas enrollment and sessions attended were computed using data from the Centers for Disease Control and Prevention’s Diabetes Prevention Recognition Program. Results Results revealed that although similar numbers of males and females were eligible for the program, only 39 321 males versus 121 007 females had enrolled in the National DPP LCP by the end of 2017 (odds ratio = 3.20; 95% CI, 3.17-3.24). The gender differences persisted even when stratifying by age or race/ethnicity. In contrast, no significant gender differences were found between the average number of sessions attended for males (14.0) and females (13.8). Discussion Results of the study can help inform efforts to market and tailor programs to appeal more directly to men and other groups that are underrepresented in the National DPP LCP.

To utilize both ferronickel slag and its sensible heat, the melting and viscosity-temperature behaviors of the B2O3 modified slags were studied first. Results show that the initial melting temperature reduces from 1612 K (1339 °C) to 1534 K (1261 °C), and the complete melting temperatures decreases from 1744 K (1471 °C) to 1696 K (1423 °C) with the increase of B2O3 from 3 to 9 wt%. However, the temperature span of the viscosity ranging in 0.5–2.5 Pa s increases from 10 K (°C) to 39 K (°C) with increasing B2O3. Then, the characterizations of the slag fibers prepared by the modified slags suggest that the addition of B2O3 decreases the mean diameter of the slag fibers from 5.6 ± 0.45 μm to 3.4 ± 0.27 μm, whereas increases their tensile strength from 1724 ± 80 MPa to 2114 ± 136 MPa. Moreover, both the glass transition temperature (Tg) and crystallization temperature (Tc) are delayed by the addition of B2O3 since boron works as network former in the slag melt structure.

Utilization of ferronickel slag as a raw material for mineral wool production not only conserves natural resources, but also achieves the sustainable development for the ferronickel industry. In order to utilize the ferronickel slag more efficiently, the melting and crystallization behaviors of the slag with the partial replacement of SiO2 by B2O3 were investigated in this paper. The results show that the initial and complete melting temperatures decreased with B2O3 substitution for SiO2, which indicates that the addition of B2O3 can reduce the energy consumption during the melting process. The incubation time of the slag in the Time Temperature Transformation (TTT) diagram increased, whereas the initial crystallization temperature in the Continuous Cooling Transformation (CCT) diagram decreased when SiO2 was substituted by B2O3. In addition, the main crystalline phases precipitated in the slags were columnar MgSiO3 and Mg2SiO4. The weakening of crystallization ability caused by the substitution of B2O3 for SiO2 will be beneficial for the improvement of fiber quality when the ferronickel slag is used as a raw material for mineral wool production.

Hepatoblastoma (HB) is the most common pediatric primary malignant liver tumor, its incidence has been increasing worldwide, but recent changes in incidence and outcomes with high population coverage are not well characterized.We defined the incidence of HB diagnosed during 2003-2017 from United States Cancer Statistics (USCS) database, and survival during 2001-2016 from the National Program of Cancer Registries (NPCR). Data were stratified by sex, race/ethnicity, age, tumor stage, county population, and diagnosis year. Incidence trends were assessed by calculating average annual percent change (AAPC) using Joinpoint regression. Differences in overall 5-year survival were estimated using Cox regression analysis.2178 HB cases with an annual incidence rate of 1.76 per million persons were identified and incidence increased over time (AAPC = 2.2, 95% confidence interval [CI], 0.9-3.6). The 5-year relative survival was 76.9% (95% CI: 74.9-78.8) and the risk of death was lower for cases diagnosed after 2009 (hazard ratio [HR] = 0.77, 95% CI: 0.63-0.94), higher for ages 3-7 years and 8-19 years compared to 0-2 years (HR = 1.38, 95% CI: 1.10-1.76 and 1.83, 95% CI: 1.31-2.70, respectively), for distant compared to locoregional stage (HR = 2.77, 95% CI: 2.27-3.36), and for non-Hispanic Black compared to non-Hispanic White cases (HR = 1.39, 95% CI: 1.02-1.84).HB incidence increased, and survival improved over the study period. Disparities in survival exist by age, race or ethnicity, and stage. Further studies could identify factors affecting increases in HB cases, inform future interventions, and address disparities in outcomes.

The collection and evaluation of family health history in a clinical setting presents an opportunity to discuss cancer risk, tailor cancer screening recommendations, and identify people with an increased risk of carrying a pathogenic variant who may benefit from referral to genetic counseling and testing. National recommendations for breast and colorectal cancer screening indicate that men and women who have a first-degree relative affected with these types of cancers may benefit from talking to a healthcare provider about starting screening at an earlier age and other options for cancer prevention. The prevalence of reporting a first-degree relative who had cancer was assessed among adult respondents of the 2015 National Health Interview Survey who had never had cancer themselves (n = 27,999). We found 35.6% of adults reported having at least one first-degree relative with cancer at any site. Significant differences in reporting a family history of cancer were observed by sex, age, race/ethnicity, educational attainment, and census region. Nearly 5% of women under age 50 and 2.5% of adults under age 50 had at least one first-degree relative with breast cancer or colorectal cancer, respectively. We estimated that 5.8% of women had a family history of breast or ovarian cancer that may indicate increased genetic risk. A third of U.S. adults who have never had cancer report a family history of cancer in a first-degree relative. This finding underscores the importance of using family history to inform discussions about cancer risk and screening options between healthcare providers and their patients.

The effect of B2O3 content on the rheological behavior and molten structure of the MgO–SiO2-based ferronickel slag were studied at a fixed (SiO2+Al2O3)/(MgO + CaO) mass ratio of 1.4. Results show that the viscosity of the slag melt decreased with the addition of B2O3, and B2O3 had a relatively little effect when its content was over 7 mass%. The break temperature of ferronickel slag reduced from 1711 to 1596 K and its apparent activation energy deceased from 95.34 ± 2.61 to 23.08 ± 1.65 kJ/mol with the addition of B2O3 from 3 to 9 mass%. Structural analyses indicate that B2O3 stripped the oxygen from the silicate structure. The formation of B–O–B structures connected by non-ring [BO3]-trihedral and [BO4]-tetrahedral structural units led to boroxol rings. These resulted in higher degree of polymerization (DOP) of both silicate and borate structures. However, the O− in [BO2O−], the dominant 2D [BO3]-trihedral structure and the formation of asymmetric Si–O–B structural units could depolymerize the network structures of ferronickel slag.

BACKGROUND: Longer intervals between prostate-specific antigen (PSA) tests for routine prostate cancer screening can reduce the harms while maintaining the benefits of screening. Limited information has been published on PSA screening frequency. The purpose of this report is to describe the number of PSA tests in the last 5 years reported by men in the United States. METHODS: Using data from National Health Interview Survey Cancer Control Supplements in 2010, 2015, and 2018, the number of PSA tests in the last 5 years reported by men ≥40 years was categorized as 4 to 5 PSA tests, 1 to 3 PSA tests, and no PSA tests. Logistic regression was used to calculate model-adjusted prevalence risk ratios (aPRs) for the number of PSA tests in the last 5 years, adjusting for age, racial-ethnic group, education, marital status, and health insurance. RESULTS: The proportion of men aged ≥70 years who reported 4 to 5 PSA tests in the last 5 years decreased from 37.2% in 2010 to 31.1% in 2018, while the proportion reporting 1 to 3 PSA tests increased from 25.5% to 31.9%. In 2018, aPRs for 4 to 5 PSA tests vs. 1 to 3 PSA tests in the last 5 years were significantly higher among men aged 70 to 79 years than among men aged 55 to 69 years. CONCLUSIONS: Men aged ≥70 years reported a small shift to less intense PSA testing between 2010 and 2018, but PSA testing intensity remained higher in men aged ≥70 years than in men aged 55 to 69 years. Published by Elsevier Inc.

The experiments were carried out to determine the transient behavior of the inclusion in Si-deoxidized stainless steel for high-grade plate. The samples were taken from three heats of the steel during the whole production process from the AOD to the mold, which were subsequently examined by an automatic scanning electron microscope with field energy dispersive spectrometer (FE-SEM and EDS). It can be summarized that appropriate calcium treatment intensity could modify inclusions into liquid ones. Excessive calcium treatment above ([Ca] = 25 ppm) will increase the melting point of the inclusions, which cannot keep in the liquid region at the solidification temperature. Therefore, the calcium addition in Si-deoxidized stainless steel should be controlled to a relatively lower value ([Ca] = 10 ppm). In addition, the content of aluminum in steel also has an important influence on the control of inclusion. When the content of aluminum ([Al] = 0.012%) is too high, the inclusions in steel are difficult to be controlled within the liquid phase. The chemical evolution of the inclusions in steel at high temperature and during solidification process were comprehensively calculated, considering all types of inclusions such as calcium oxide, aluminum oxide, silicon oxide, calcium aluminate, calcium silicate, mullite, and liquid inclusion. The thermodynamic calculations are in good agreement with experimental results, which can predict the formation of the inclusions in Si-deoxidized stainless steels.

In the production of mineral wool, the melting and crystallization behaviors of slag are the key issues to determine the final quality of mineral wool. In this study, three synthetic ferronickel slags with different B2O3 contents have been prepared, and the effect of B2O3 on the melting ranges of the slags has been investigated by single hot thermocouple technique (SHTT). Meanwhile, the isothermal crystallization characteristics of the samples were studied by high-temperature confocal scanning laser microscope (CSLM). The results showed that the initial and complete melting temperatures decreased with the increase of B2O3 content. Meanwhile, from the time-temperature-transformation diagrams, the crystallization incubation time increased with the increase of B2O3. The crystal morphology formed in the slags was columnar.

Authors developed an interactive map visualizing county level availability of Diabetes Self-Management Education and Support (DSMES) site or program locations. Location data were overlaid with diabetes prevalence data and socio-economic status data. Over 4200 locations were geocoded including 3471 sites (American Diabetes Association recognized) and 802 program locations (American Association of Diabetes Educators accredited). Counties were characterized as having or not having DSMES class locations. Counties were additionally characterized based on tertiles of diabetes prevalence and socio-economic disadvantage (using the Area Deprivation Index (ADI) score). This analysis showed that 48 percent of U.S. counties (1515/3142 counties and county equivalents) had a DSMES program with at least one site or program location. Approximately 39% of counties in the highest diabetes prevalence tertile (greatest diabetes burden) had DSMES programs compared to 53% in the middle tertile of diabetes prevalence and 54% in the lowest tertile of diabetes prevalence. Approximately 26% of counties in the tertile with highest ADI scores (representing greatest socio-economic disadvantage) had DSMES programs compared to 48% in the middle tertile and 69% percent in the tertile with the lowest ADI scores (least socio-economic disadvantage). This interactive map is a tool that can be used at a national level and by state and local health departments and others to prioritize establishment and expansion of programs in underserved counties with higher rates of diabetes prevalence and greater socio-economic disadvantage. Disclosure B. Jayapaul-Philip: None. S. Dai: None. E. Woghiren: None. G.E. Rutledge: None.

The production of mineral wool from silicomanganese slag is a new way of resource utilization of metallurgical wastes. The crystallization and viscosity properties of waste slag are the basis of the production of mineral wool. In this study, four synthetic silicomanganese slag with various CaO contents were investigated for their crystallization tendency and viscosity. The crystallization behavior and the viscosity of the samples have been investigated by using a confocal laser scanning microscopy (CLSM) and a viscometer, respectively. The type and morphology of crystalline phases were determined by using scanning electron microscopy (SEM) with an Energy Dispersive Spectrometer (EDS). The experimental results show that the crystallinity of silicomanganese slag increases with the increase of CaO content. The crystallinity of Sample 1 is very poor, and the final sample is glass phase. In the crystallization process of Sample 2, the crystallization is not obvious, drift and grow, and finally the liquid phase in the slag continuously precipitates into fine grains. At 1350 °C, irregular crystals appeared in Sample 3, which gradually cooled down, and the number and volume increased rapidly. When the temperature is 1375 °C, many fine crystals appear in the Sample 4. These crystals are also irregular and can move freely. When the temperature is 1350 °C, the crystal grows up gradually and appears rectangles and squares, and the fluidity of crystal becomes worse. The main precipitates of Sample 2 and Sample 3 were elongated anorthite, and the precipitate of Sample 4 was cubic melilite. Furthermore, the viscosity of silicomanganese slag increases with the addition of CaO, and the main reason for the increase of slag viscosity is the precipitation of crystal in slag. When the crystal is small and has fluidity, it has little effect on viscosity. Once the crystal is fixed and grows up, however, the viscosity increases rapidly.

Pipeline steel is widely used in various industries, and the sulfur content and inclusions in steel have a significant impact on performance, which determines whether the steel quality is qualified. The experiments were carried out to explore the sulfur content and inclusion evolution of pipeline steel which was deoxidized by Si–Mn–Al with “EAF-LF-VD-T-CC”. The samples of molten steel and slag were taken during the process of LF-VD-Tundish after EAF tapping. The kinetics model was established to simulate the desulfuration process of molten steel in actual production, obtaining a result which the error is within 3 ppm. It can be summarized that proper calcium treatment can transform the inclusion into a liquid inclusion, the value of [Ca] ranges from 25 to 45 ppm. Too high and lower calcium treatment can cause the compositions of inclusions to deviate from the liquid phase area, while too low calcium treatment will increase the overall size and density of the inclusions. In addition, the evolution of inclusion in steel at refining temperature and during solidification process was comprehensively calculated, considering all types of inclusions such as calcium oxide, magnesium oxide, aluminum oxide, calcium sulfide, spinel, calcium aluminate and liquid inclusion. The thermodynamic calculations are in good agreement with experimental results, which can predict the formation of the inclusions in Si–Mn–Al deoxidized pipeline steel.

Objectives. We evaluated heart disease death rates among American Indians and Alaska Natives (AI/ANs) and Whites after improving identification of AI/AN populations. Methods. Indian Health Service (IHS) registration data were linked to the National Death Index for 1990 to 2009 to identify deaths among AI/AN persons aged 35 years and older with heart disease listed as the underlying cause of death (UCOD) or 1 of multiple causes of death (MCOD). We restricted analyses to IHS Contract Health Service Delivery Areas and to non-Hispanic populations. Results. Heart disease death rates were higher among AI/AN persons than Whites from 1999 to 2009 (1.21 times for UCOD, 1.30 times for MCOD). Disparities were highest in younger age groups and in the Northern Plains, but lowest in the East and Southwest. In AI/AN persons, MCOD rates were 84% higher than UCOD rates. From 1990 to 2009, UCOD rates declined among Whites, but only declined significantly among AI/AN persons after 2003. Conclusions. Analysis with improved race identification indicated that AI/AN populations experienced higher heart disease death rates than Whites. Better prevention and more effective care of heart disease is needed for AI/AN populations.

Author(s): Go, Alan S; Mozaffarian, Dariush; Roger, Veronique L; Benjamin, Emelia J; Berry, Jarett D; Blaha, Michael J; Dai, Shifan; Ford, Earl S; Fox, Caroline S; Franco, Sheila; Fullerton, Heather J; Gillespie, Cathleen; Hailpern, Susan M; Heit, John A; Howard, Virginia J; Huffman, Mark D; Judd, Suzanne E; Kissela, Brett M; Kittner, Steven J; Lackland, Daniel T; Lichtman, Judith H; Lisabeth, Lynda D; Mackey, Rachel H; Magid, David J; Marcus, Gregory M; Marelli, Ariane; Matchar, David B; McGuire, Darren K; Mohler, Emile R; Moy, Claudia S; Mussolino, Michael E; Neumar, Robert W; Nichol, Graham; Pandey, Dilip K; Paynter, Nina P; Reeves, Matthew J; Sorlie, Paul D; Stein, Joel; Towfighi, Amytis; Turan, Tanya N; Virani, Salim S; Wong, Nathan D; Woo, Daniel; Turner, Melanie B; American Heart Association Statistics Committee and Stroke Statistics Subcommittee

Author(s): Go, Alan S; Mozaffarian, Dariush; Roger, Veronique L; Benjamin, Emelia J; Berry, Jarett D; Borden, William B; Bravata, Dawn M; Dai, Shifan; Ford, Earl S; Fox, Caroline S; Franco, Sheila; Fullerton, Heather J; Gillespie, Cathleen; Hailpern, Susan M; Heit, John A; Howard, Virginia J; Huffman, Mark D; Kissela, Brett M; Kittner, Steven J; Lackland, Daniel T; Lichtman, Judith H; Lisabeth, Lynda D; Magid, David; Marcus, Gregory M; Marelli, Ariane; Matchar, David B; McGuire, Darren K; Mohler, Emile R; Moy, Claudia S; Mussolino, Michael E; Nichol, Graham; Paynter, Nina P; Schreiner, Pamela J; Sorlie, Paul D; Stein, Joel; Turan, Tanya N; Virani, Salim S; Wong, Nathan D; Woo, Daniel; Turner, Melanie B; American Heart Association Statistics Committee and Stroke Statistics Subcommittee

Background:Previous studies have examined participation in specific leisure-time physical activities (PA) among US adults. The purpose of this study was to identify specific activities that contribute substantially to total volume of leisure-time PA in US adults.Methods:Proportion of total volume of leisure-time PA moderate-equivalent minutes attributable to 9 specific types of activities was estimated using self-reported data from 21,685 adult participants (≥ 18 years) in the National Health and Nutrition Examination Survey 1999–2006.Results:Overall, walking (28%), sports (22%), and dancing (9%) contributed most to PA volume. Attributable proportion was higher among men than women for sports (30% vs. 11%) and higher among women than men for walking (36% vs. 23%), dancing (16% vs. 4%), and conditioning exercises (10% vs. 5%). The proportion was lower for walking, but higher for sports, among active adults than those insufficiently active and increased with age for walking. Compared with other racial/ethnic groups, the proportion was lower for sports among non-Hispanic white men and for dancing among non-Hispanic white women.Conclusions:Walking, sports, and dance account for the most activity time among US adults overall, yet some demographic variations exist. Strategies for PA promotion should be tailored to differences across population subgroups.

associated with early development of cardiovascular disease and risk for premature death. High sodium intake and overweight/ obesity are recognized as risk factors for hypertension in children. WHAT THIS STUDY ADDS: These results show that usual sodium intake was positively associated with systolic blood pressure and risk for pre-high blood pressure and high blood pressure among US children. The data indicate a synergistic interaction between sodium intake and weight status on risk for high blood pressure. abstract To assess the association between usual dietary sodium intake and blood pressure among US children and adolescents, over- all and by weight status. METHODS: Children and adolescents aged 8 to 18 years (n = 6235) who participated in NHANES 2003-2008 comprised the sample. Subjects' usual sodium intake was estimated by using multiple 24-hour dietary recalls. Linear or logistic regression was used to examine association between sodium intake and blood pressure or risk for pre-high blood pressure and high blood pressure (pre-HBP/HPB). RESULTS: Study subjects consumed an average of 3387 mg/day of sodium, and 37% were overweight/obese. Each 1000 mg per day sodium intake was associated with an increased SD score of 0.097 (95% confidence interval (CI) 0.006-0.188, ∼1.0 mmHg) in systolic blood pressure (SBP) among all subjects and 0.141 (95% CI: -0.010 to 0.298, ∼1.5 mm Hg) increase among overweight/obese subjects. Mean adjusted SBP increased progressively with sodium intake quartile, from 106.2 mm Hg (95% CI: 105.1-107.3) to 108.8 mm Hg (95% CI: 107.5-110.1) overall (P = .010) and from 109.0 mm Hg (95% CI: 107.2-110.8) to 112.8 mm Hg (95% CI: 110.7-114.9; P = .037) among those overweight/obese. Adjusted odds ratios comparing risk for pre-HBP/HPB among subjects in the highest versus lowest sodium intake quartile were 2.0 (95% CI: 0.95-4.1, P = .062) overall and 3.5 (95% CI: 1.3-9.2, P = .013) among those overweight/obese. Sodium intake and weight status appeared to have synergistic effects on risk for pre-HBP/HPB (relative excess risk for interaction = 0.29 (95% CI: 0.01-0.90, P , .05). CONCLUSIONS: Sodium intake is positively associated with SBP and risk for pre-HBP/HPB among US children and adolescents, and this as- sociation may be stronger among those who are overweight/obese. Pediatrics 2012;130:611-619

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .e3 1. About These Statistics. . . . . . . . . . . . . . . . . . . . . . . . . .e7 2. American Heart Association's 2020 Impact Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .e10 3. Cardiovascular Diseases . . . . . . . . . . . . . . . . . . . . . . .e21 4. Subclinical Atherosclerosis . . . . . . . . . . . . . . . . . . . . .e45 5. Coronary Heart Disease, Acute Coronary Syndrome, and Angina Pectoris . . . . . . . . . . . . . . . . . .e54 6. Stroke (Cerebrovascular Disease). . . . . . . . . . . . . . . . .e68 7. High Blood Pressure . . . . . . . . . . . . . . . . . . . . . . . . . .e88 8. Congenital Cardiovascular Defects. . . . . . . . . . . . . . . .e97 9. Cardiomyopathy and Heart Failure. . . . . . . . . . . . . . .e102 10. Disorders of Heart Rhythm . . . . . . . . . . . . . . . . . . . .e107 11. Other Cardiovascular Diseases. . . . . . . . . . . …

Objective To investigate possible age-related changes in associations between polymorphisms in the fat mass and obesity-associated (FTO) gene and higher body mass index (BMI). Design and Subjects Multilevel mixed regression models were used to examine associations between four FTO variants and longitudinal BMI profiles in non-Hispanic white and African American children and adolescents 8 - 17 years of age from two different longitudinal cohort studies, the Bogalusa Heart Study (BHS) and Project HeartBeat! (PHB). In the BHS, there were 1551 examinations of 478 African Americans and 3210 examinations of 1081 non-Hispanic whites; in PHB, there were 971 examinations of 131 African Americans and 4458 examinations of 505 non-Hispanic whites. Results In African Americans, no significant FTO associations with BMI were found. In non-Hispanic whites, linkage disequilibrium among all four variants made haplotype analysis superfluous, so we focused on the single-nucleotide polymorphism (SNP), rs9939609. In longitudinal multilevel models, the A/A genotype of rs9939609 was associated with higher BMI in non-Hispanic whites in both cohorts at all ages. A significant age-by-genotype interaction found only in the BHS cohort predicted that in those with the A/A genotype, BMI would be approximately 0.7 kg/m2 higher at age 8, and approximately 1.6 kg/m2 higher at age 17 than in those with A/T or T/T genotypes. The design of Project HeartBeat! limited follow-up of any single individual to four years, and may have reduced the ability to detect any age-by-genotype interaction in this cohort. Conclusions The A/A genotype of rs9939609 in the FTO gene is associated with higher longitudinal BMI profiles in non-Hispanic whites from two different cohorts. The association may change with age, with the A/A genotype being associated with a larger BMI difference in late adolescence than in childhood, though this was observed only in the Bogalusa Heart Study cohort and requires verification.

Background Clinicians use several measures to estimate adiposity. Body mass index (BMI), although not a measure of adiposity, is commonly used to define weight status. Percent body fat (%BF) measures total body fatness, which is composed of central and peripheral fat, estimated by waist circumference (WC) and skinfold thickness, respectively. Abnormal increases in fat during puberty may reflect an increased risk of developing cardiovascular disease. Therefore, it is important to establish the normal patterns of change in clinically relevant measures of adiposity. Purpose To describe the normal patterns of change in clinical measures of adiposity during puberty. Design/Methods Multilevel modeling and linear regression analyses of 642 children in Project HeartBeat!, aged 8–18 years (non-black and black), who had assessments of BMI, %BF, WC, sums of 2- and 6-skinfolds, and pubertal stage (PS) triennially between 1991 and 1995. Results In males, the normal pattern from PS1 to PS5 is for %BF to decrease, skinfold thickness to remain stable, and WC to increase. However, after adjusting for height, WC does not change. In females, %BF remains stable from PS1 to PS5, whereas skinfold thickness increases. As in males waist-height ratio does not change, indicating that central adiposity does not normally increase during puberty. Although BMI increases in both genders and races from PS1 to PS5, mean values at PS5 were well below 25 kg/m 2 . Conclusions During puberty, increase in %BF is abnormal in females and even more so in males. Likewise, increase in waist-height ratio is also abnormal and may suggest an increased risk for adiposity-associated morbidity.

Major cardiovascular disease (CVD) risk factors begin development in childhood and adolescence. Project HeartBeat! studied early development of these risk factors as growth processes. Growth, body composition, sexual maturation, major CVD risk factors, and cardiac structure and function were monitored every 4 months for up to 4 years among 678 children and adolescents (49.1% girls; 20.1% blacks) aged 8, 11, or 14 years at study entry. All resided in The Woodlands or Conroe TX. Interviews were conducted at entry and annually on diet, physical activity, and health history of participants and their families. Data were collected from 1991 to 1995, and study investigators continue data analysis and reporting. Overlap in ages at examination among three cohorts (aged 8–12, 11–15, and 14–18 years at baseline) and use of multilevel modeling methods permit analysis of some 5500 observations on each principal variable for the synthetic cohort from ages 8 to 18 years. The mixed-longitudinal design provides trajectories of change with age, for total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides; systolic, and fourth-phase and fifth-phase diastolic blood pressure, and left ventricular mass. These trajectories are then related to concurrent measures of multiple indices of body composition and sexual maturation and adjusted for energy intake and physical activity. The data provide valuable insights into risk factor development and suggest a fresh approach to understanding influences on blood lipids, blood pressure, and left ventricular mass during the period of childhood and adolescence, a period of dynamic change in these risk factors.

Background Few investigations have examined whether associations between the apolipoprotein E genotype (apo E) and total cholesterol or LDL-C are modified or explained by other characteristics. The objective of this study was to explore effects of behavioral characteristics, physical growth, body composition, sexual maturation, and endocrine function on age trajectories of total cholesterol and LDL-C by apo E in adolescent girls. Methods Participants were 247 Caucasian adolescent girls followed for 4 years. Apo E genotyping and plasma lipid concentrations were determined from fasting blood samples using standard enzymatic methods. Age; gender; fat-free mass (FFM); BMI; percent body fat (PBF); sexual maturation (pubic hair, Tanner Stages 1–5); estradiol concentration (EST); energy intake; and physical activity were collected or calculated with standard methods. Results In models including the proposed explanatory variables, apo E genotype remained strongly associated with total cholesterol and LDL-C. Girls with the epsilon (e)3/3 and e3/4 genotypes (where e is the protein isoform of the apo E gene), relative to those with e2/3, had total cholesterol and LDL-C values 16–23 mg/dL higher throughout adolescence. Age–apo E interaction terms remained significant. FFM, BMI, PBF, pubic-hair stage, and EST showed a significant effect on total cholesterol and LDL-C. When the combination of pubic-hair stage, EST, and one of FFM, BMI, and PBF was included in total cholesterol or LDL-C models, only EST was significant. Conclusions Adolescent girls with e3/3 and e3/4 genotypes had higher total cholesterol and LDL-C and showed different patterns of change, compared to those with e2/3 genotype. These apo E effects were independent of behavioral characteristics, physical growth, body composition, sexual maturation, and endocrine function. Girls with e3/3 or e3/4 genotypes may be at risk for elevated total cholesterol and LDL-C later in life.

Background It is unclear to what extent factors affecting energy balance contribute to the development of body fatness in youth. The objective of the current study was to describe the relationship of physical activity, energy intake, and sedentary behavior to BMI, fat free–mass index (FFMI), and fat mass index (FMI) in children aged 10–18 years. Methods In the subsample studied, participants were 245 girls and 227 boys (aged ≥10 years at entry or during follow-up assessments, or aged 11–14 years at entry) followed for 4 years from entry at ages 8, 11, or 14 years. At baseline and anniversary examinations, trained interviewers used a questionnaire to assess time spent daily in moderate-to-vigorous physical activity (MVPA), sedentary behavior, and energy intake (kcal/day). Sexual maturation was assessed by direct observation of pubic-hair development (Tanner Stages 1–5). Triplicate recordings of height and weight were used to estimate BMI by the standard formula (kg/m 2 ); bioelectric impedance was used to estimate percent body fat for calculating FFMI and FMI (kg/m 2 ). Multilevel models were used to examine the association of MVPA, energy intake, and sedentary behavior with BMI, FFMI, and FMI. Data were analyzed in 2007–2008. Results Energy intake was unrelated to FMI or FFMI in models adjusted for age or sexual maturation or in any model to BMI. Sedentary behavior was unrelated to FMI in any model or to FFMI or BMI in models adjusted for age or sexual maturation. MVPA was inversely related to FMI. Conclusions In children aged 10–18 years, MVPA was inversely associated with fat mass and with BMI. Investigations in youth of dietary intake and physical activity, including interventions to prevent or reverse overweight as represented by BMI, should address its fat and lean components and not BMI alone.

Background Body composition and fat distribution change dramatically during adolescence. Data based on longitudinal studies to describe these changes are limited. The aim of this study was to describe age-related changes in fat free–mass index (FFMI) and fat mass index (FMI), which are components of BMI, and waist circumference (WC) in participants of Project HeartBeat!, a longitudinal study of children. Methods Anthropometric measurements and body composition data were obtained in a mixed longitudinal study of 678 children (49.1% female, 20.1% black), initially aged 8, 11, and 14 years, every 4 months for 4 years (1991–1995). Trajectories of change from ages 8 to 18 years were measured for FFMI, FMI, and WC. Because of the small number of observations for black participants, trajectories for this group were limited to ages 8.5–15 years. Results Body mass index, FFMI, and WC increased steadily with age for all race–gender cohorts. However, in nonblack girls, FFMI remained constant after about age 16 years. For black boys and girls, FFMI was similar at age 8.5 years but increased more steeply for black boys by age 15 years. In girls, FMI showed an upward trend until shortly after age 14 years, when it remained constant. In boys, FMI increased between age 8 years and age 10 years, and then decreased. Conclusions The extent to which each component of BMI contributes to the changes in BMI depends on the gender, race, and age of the individual. Healthcare providers need to be aware that children who show upward deviation of BMI or BMI percentiles may have increases in their lean body mass rather than in adiposity.

Project HeartBeat! was a longitudinal “growth” study of cardiovascular disease (CVD) risk factors and body composition in childhood and adolescence. Its findings demonstrate patterns of change from ages 8 to 18 years in anthropometric indicators of adiposity, blood lipid components, and blood pressure measurements, as well as the varying inter-relations among these patterns. Especially noteworthy are differences among associations between the two components of BMI (kg/m2)—the lean or fat-free mass index, and the fat mass index—and each of several CVD risk factors. Policy development and public health recommendations for CVD prevention beginning in childhood have evolved over 30 years or more. A new impetus to action is the recognized increase in the prevalence of childhood overweight and obesity. Intervention to prevent obesity can have a major impact in preventing CVD risk factors more broadly. Opportunities to strengthen interventions for CVD prevention in childhood and adolescence include updated algorithms for monitoring body composition, blood lipids, and blood pressure throughout childhood and adolescence through use of the Project HeartBeat! study results.

Background Associations among dietary intake, physical activity, and cardiovascular disease (CVD) risk factors are inconsistent among male and female youth, possibly from lack of adjustment for pubertal status. The purpose of this report is to describe the associations of CVD risk factors among youth, adjusted for sexual maturation. Methods Data analyzed in 2007 from a sumsample of 556 children aged 8, 11, and 14 years in Project HeartBeat!, 1991–1993, provide cross-sectional patterns of CVD risk factors by age and gender, adjusting for sexual maturation, within dietary fat and physical activity categories. Results Girls consuming moderate- to high-fat diets were significantly less physically active than those consuming low-fat diets. Boys and girls consuming high-fat diets had higher saturated fat and cholesterol intakes than children in low-fat categories. Boys had no significant differences in physical activity, blood pressure, waist circumference, or plasma cholesterol levels across fat categories. Girls' plasma cholesterol levels showed no significant differences across fat categories. Dietary intake did not differ across moderate-to-vigorous physical activity (MVPA) categories within gender. There were no differences in BMI by fat or MVPA categories for either gender. Girls' waist circumference differed significantly by fat category, and systolic blood pressure differed significantly across fat and MVPA categories. Boys' fifth-phase diastolic blood pressure was significantly different across MVPA categories. Conclusions Girls consuming atherogenic diets were significantly less physically active than those with low fat intakes, whereas boys consuming high-fat diets did not show differences in physical activity measures. With the prevalence of overweight rising among youth, the impact of atherogenic diets and sedentary lifestyles on CVD risk factors is of concern to public health professionals.

Background Longitudinal data on the normal development of blood lipids and its relationships with body fatness in children and adolescents are limited. Objectives of the current analysis were to estimate trajectories related to age for four blood lipid components and to examine the impact of change in body fatness on blood lipid levels, comparing estimated effects among adiposity indices, in children and adolescents. Methods Three cohorts, with a total of 678 children (49.1% female, 79.9% nonblack) initially aged 8, 11, and 14 years, were followed at 4-month intervals (1991–1995). Total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride levels were determined in blood samples taken following fasting. Body fatness was measured by five adiposity indices—BMI; percent body fat (PBF); abdominal circumference; and the sums of six and of two skinfold thicknesses. Trajectories of change in blood lipid levels from ages 8 to 18 years were estimated by gender and race. The impact of change in body fatness on lipid levels was evaluated for each index, adjusting for gender, race, and age. Results All lipid components varied significantly with age. Total cholesterol decreased by ∼19 mg/dL from ages 9 to 16 years in girls and more steeply from ages 10 to 17 years in boys. LDL-C decreased monotonically, more steeply in boys than in girls. It was higher among nonblacks than among blacks. HDL-C increased monotonically in girls, mainly from ages 14 to 18 years, but fluctuated sharply among boys. Levels of HDL-C were higher among blacks than among nonblacks. The levels of triglycerides increased from ages 8 to 12 years among girls and, almost linearly, from ages 8 to 18 years among boys. The levels of triglycerides were higher among nonblacks than among blacks. Increase in body fatness was significantly associated with increases in total cholesterol, LDL-C, and triglyceride levels. Significant interactions between the adiposity indices (except for BMI) and gender indicated smaller impacts of change in body fatness on total cholesterol and LDL-C in girls than in boys. The estimated impact on triglycerides was weaker among blacks than among nonblacks, except for PBF. Change in body fatness was negatively associated with HDL-C. The results remained essentially unchanged after adjustments for energy intake, physical activity, and sexual maturation. Conclusions Patterns of change with age in blood lipid components vary significantly among gender and racial groups. Increase in body fatness among children is consistently associated with adverse change in blood lipids. Evaluation of blood lipid level should take into account variation by age, gender, and race. Intervention through body-fat control should help prevent adverse lipid levels in children and adolescents.

Background Systolic and fourth-phase and fifth-phase diastolic blood pressure (SBP, DBP4, DBP5) have appeared to differ in their patterns of age-related change, and SBP and DBP5 differ in their respective associations with anthropometric variables. Project HeartBeat! investigated trajectories of change in SBP, DBP4, and SBP5 with age and their relationships with indices of adiposity, controlling for energy intake, physical activity, and sexual maturation. Methods Project HeartBeat! was a mixed longitudinal study in 678 black and white girls and boys aged 8, 11, or 14 years at first examination, followed at 4-month intervals for up to 4 years (1991–1995). A statistical model was estimated for the trajectory of change in each blood pressure measure from ages 8 to 18 years. Results For SBP, DBP4, and DBP5, the trajectories were sigmoid, parabolic, and linear in form, respectively. SBP and DBP4 differed significantly by gender; DBP4 and DBP5 were significantly related to race. Adjusted for age, gender, and race, all relationships of adiposity-related variables (percent body fat, abdominal circumference, skinfold thickness, and BMI and its fat and fat-free components) with SBP were positive and significant. Corresponding relationships for DBP4 were notably weaker but significant, and for DBP5, weak or not significant. After adjusting for diet, physical inactivity, and maturation, no DBP5 relationship with adiposity indices remained significant. Conclusions SBP, DBP4, and DBP5 are distinct in patterns of change with age, relationships to gender and race, and patterns of association with multiple anthropometric indices related to adiposity.

Background Parental obesity and TV viewing are risk factors for childhood obesity. This study assessed the association of children's TV viewing and computer use with body mass and examined whether parental weight status modified the association. Methods Cross-sectional associations of parental weight status, hours of TV viewing and computer use, and children's body composition were studied in a subsample of 526 black and nonblack children, aged 8, 11, and 14 years at baseline, enrolled in Project HeartBeat!, a longitudinal study of cardiovascular disease risk factors, 1991–1995. BMI, fat-free mass (FFM), and percent body fat (PBF) were calculated from children's body composition measured at baseline. Children's TV viewing and computer use habits and parental height and weight were self-reported. Multivariate regression analysis was used in assessing inter-relations of parental weight status and child's TV viewing and computer use habits with BMI, FFM, PBF, and risk for overweight status (BMI ≥85th percentile), adjusting for age, gender, race, and Tanner stage. Results Children of one or two overweight/obese parents watched an average of 22±6 minutes or 30±11 minutes more TV per day than children of normal-weight parents, respectively (both p 2 and 1.14% (both p p interaction Conclusions These study findings are consistent with a genetic contribution of parental weight; however, overweight/obese parents may also exhibit behavior patterns that negatively influence children's TV viewing and have an impact on child overweight status. The effect of parental BMI on children's BMI may have both a genetic and an environmental linkage.

Background Left ventricular mass (LVM) is a strong predictor of cardiovascular disease in adults. Available study findings on effects of body fatness on LVM in children are inconsistent. Understanding the impact of body fat on LVM in children may help prevent excessive LVM through measures to reduce overweight and obesity. Methods Healthy children ( n =678) aged 8, 11, and 14 years at baseline were examined at 4-month intervals for up to 4 years (1991–1995); 4608 valid measurements of LVM were obtained with M-mode echocardiography. A multilevel linear model was used for analysis. The impact of body size was examined by adding separately nine body-size indicators to a basic LVM–gender–age model. The impact of body fatness was tested by introducing four body-fatness indicators into the nine models, yielding 36 models. Results All body-size indicators showed strong, positive effects on LVM. In models containing weight or body surface area (measuring both fat-free and fat contributions to body size), additional effects of body fatness were negative; in models containing fat-free mass (FFM) or height (both measuring body size independent of body fat), increased body fatness was related to a significant increase in LVM. For example, in models with FFM as a body-size indicator, a 1-SD increase in percent body fat or fat mass was related to a 5.4- or 7.2-g increase in LVM, respectively. Conclusions Effects of body size on LVM attributable to fat-free body mass can be distinguished from those attributable to fat body mass; both are independent, positive predictors, but the former is the stronger determinant. When a body-size indicator not independent of body fat is used as a predictor, effects of fat-free body mass and fat body mass are forced to relate to the same indicator; because their magnitudes are estimated to be equal, the effect of fat body mass is overestimated. Thus, when an additional body-fatness indicator is included in the prediction of LVM, the additional estimated effect related to the indicator appears to be negative.

Project HeartBeat! (1991–1995) was an observational study of the development of cardiovascular disease (CVD) risk factors in childhood and adolescence using an accelerated longitudinal design. The purpose of this paper is to explain the analytic methods used in the study, particularly multilevel statistical models. Measurements of hemodynamic, lipid, anthropometric, and other variables were obtained in 678 children who were enrolled in three cohorts (baseline ages 8, 11, and 14 years) and followed for 4 years, resulting in data for children aged 8–18 years. Patterns of change of blood pressure, serum lipid concentration, and obesity with age, race, and gender were of particular interest. The design specified 12 measurements of each outcome variable per child. Multilevel models were used to account for correlations resulting from repeated measurements on individuals and to allow use of data from incomplete cases. Data quality–control measures are described, and an example of multilevel analysis in Project HeartBeat! is presented. Multilevel models were also used to show that there were no differences attributable to the cohorts, and combining data from the three age cohorts was judged to be reasonable. Anthropometric data were compared with national norms and shown to have similar patterns; thus, the patterns seen in the CVD risk factors may be generalized, with some caveats, to the U.S. population of children.

Objective To describe longitudinal changes in plasma lipid levels and pubertal stage in youths from age 8-18 years, in Project HeartBeat! Study design Fasting blood samples and pubertal stage, using physical assessment of secondary sex characteristics, were obtained every 4 months for up to 4 years in a mixed longitudinal study of 633 children (49.1% female, 20.1% black), initially aged 8, 11, and 14 years. Total cholesterol, low density lipoprotein-cholesterol, high density lipoprotein-cholesterol, triglycerides (TG), and nonhigh density lipoprotein-cholesterol measurements were obtained. Data were collected from 1991-1995. Results Pubertal stage correlations with age varied among all race-sex groups (range, r = 0.61-0.70), and a given pubertal stage could represent a range of 5 years or more of chronological age. Throughout puberty, levels of total cholesterol, low density lipoprotein-cholesterol, and nonhigh density lipoprotein-cholesterol decreased, TG in males increased, and high density lipoprotein-cholesterol and TG in females showed no changes. Within a given pubertal stage, plasma lipid levels tended to differ by race, sex, or both. Conclusions Lipid levels change markedly by pubertal stage, and patterns differ by sex and race. Chronological age ranges widely within a given pubertal stage and is an insensitive indicator of pubertal stage and the related changes in lipid levels. Pubertal development should be considered when determining screening criteria to identify youths with adverse blood lipid levels.

Background:Information on specific types of physical activities in which US adults participate is important for community and program development to promote physical activity.Methods:Prevalence of participation and average time spent for 33 leisuretime aerobic activities and 10 activity categories were calculated using self-reported data from 22,545 participants aged ≥ 18 years in the National Health and Nutrition Examination Survey 1999–2006.Results:Overall, 38% of US adults reported no leisure-time physical activities, and 43% reported 1 or 2 activities in the past 30 days. Walking was the most frequently reported activity for both men (29%) and women (38%). Among walkers, the average time spent walking was 198 minutes/week for men and 152 minutes/week for women. The most reported activities for men after walking were bicycling and yard work, and for women were aerobics and dance. For most activity categories, participation was lower among adults aged ≥ 65 years than among younger adults, and among Mexican Americans and non-Hispanic blacks than among non-Hispanic whites. Participation in most categories increased with increasing educational attainment.Conclusions:Participation in physical activity differs by types of activities and demographic characteristics. Physical activity promotion programs should take these differences into account when developing intervention strategies.

To determine the success of a state prevention program and to make timely and effective public health decisions, the program's outcomes must be monitored and evaluated. Twenty-one performance measures for the National Heart Disease and Stroke Prevention Program have been developed from the Healthy People 2010 objectives for heart disease and stroke, from performance measures developed in response to the Government Performance and Results Act (GPRA), and from a fiscal year program announcement. We assessed the availability of state surveillance systems that could address these measures. Current state data were available for only six of the 16 Healthy People 2010 objectives, one of the two GPRA performance measures, and for all three of the surveillance-related measures recommended in the program announcements. If states are to meet the Healthy People 2010 objectives related to high blood pressure, cholesterol, and emergency care during a cardiac arrest, new surveillance resources will be required at both the national and state levels. These would include a national surveillance system of state registries of acute cardiac arrest care, as well as state health examination surveys.

Cholesterol screening in children and adolescents with a positive family history of cardiovascular disease or parental history of hypercholesterolemia was recommended by the Expert Panel on Blood Cholesterol Levels in Children and Adolescents in 1991. A serum total cholesterol concentration of 170–199 mg/dl is classified as ‘borderline’ and 200 mg/dl or greater as ‘high’, for males and females aged 2–19 years. The cutpoints, 170 and 200 mg/dl were thought to approximate the 75th and 95th percentiles of the Lipid Research Clinics Prevalence Study (North America) distribution for ages 0–19 years. However, total cholesterol concentration varies by age and sex in childhood and adolescence. This knowledge prompted analysis of recent data from Project HeartBeat!, a community-based longitudinal study in Texas, and from a national population sample survey, the Third National Health and Nutrition Examination Survey, to investigate the impact of this variation on projected screening results. Effects of age (from 8 to 17 years), sex, and race (black and non-black or white) were evaluated through linear regression techniques. The models demonstrate a marked decline in serum total cholesterol concentration with age following the pre-teen peak. Significant effects of sex are observed in both data sets and by race in one of them. The 75th and 95th percentile values range from 164 to 200 and 193 to 229 mg/dl, respectively, with the highest values at the earliest ages. Substantially greater proportions of children and adolescents than 25% or 5% would be screened positive at cutpoints of 170 or 200 mg/dl, especially at younger ages—but for older males smaller proportions would be positive. Considering the merits of variable vs. fixed screening criteria for total cholesterol concentration, we conclude that age- and sex-specific criteria are preferable for selective screening.

In this study, the feasibility of the carburization of vanadium-bearing hot metal was first investigated by thermodynamic analysis. Next, three carburizers, namely a low-nitrogen carburizer, anthracite, and coke, were used for carburization of 500 g of vanadium-bearing hot metal at 1450 °C, 1500 °C, and 1550 °C, respectively. The carbon increments for the low-nitrogen carburizer, anthracite and coke followed decreasing order in the temperature range from 1450 °C to 1550 °C. Anthracite was the most cost-effective carburizer. Hence, anthracite is used in pilot-scale experiments of the vanadium-bearing hot metal (100 kg and 200 kg). Finally, vanadium extraction experiments of the vanadium-bearing hot metal were carried out in a top-bottom-combined blowing induction furnace. It is proved that the average superheat degree of semi-steel increases from 100 °C to 198 °C by the carburization of vanadium-containing hot metal.

To compare growth patterns of obesity indices derived from body composition and anthropometric measures, the authors analyzed data from Project HeartBeat!, a longitudinal study of cardiovascular disease risk factors in childhood and adolescence. A total of 678 children initially aged 8, 11, and 14 years in The Woodlands and Conroe, Texas, were enrolled and followed with 4-monthly examinations between October 1991 and August 1995. Trajectories of change from age 8 years to age 18 years were estimated for body mass index, percent body fat, abdominal circumference, the sum of two skinfolds, and the sum of six skinfolds. All indices varied importantly with age. Percent body fat, sum of two skinfolds, and sum of six skinfolds shared similar growth patterns, with strong divergence between males and females. Males' body fat decreased with age and females' increased or remained nearly constant with age. In contrast, both body mass index and abdominal circumference increased monotonically with age in both sexes, exhibiting little sex difference as children reached late adolescence. Sex differences were more striking among Blacks than among non-Blacks. The authors conclude that growth patterns of adiposity differ according to the measure chosen. Furthermore, changes in different obesity indices may not relate in the same way to changes in blood pressure or blood lipid concentrations.

OBJECTIVE: To investigate whether within-individual variation is a factor in the generally reported poor tracking of central body fat distribution (CBFD) during development and whether two measurements of CBFD during each measurement occasion would improve the estimate of tracking over time. METHODS: A longitudinal study compared the results of two measurements of body fat (BF) and CBFD during each measurement occasion to the results of one measurement of BF and CBFD during each occasion every 4 months over 1–3 y. A total of 345 boys and 333 girls in three age cohorts of 8, 11 and 14 y at baseline were examined. BF variables were: body mass index (BMI); fat mass and percentage body fat from bioelectrical impedance; two skinfold sums; and abdominal circumference. CBFD variables were: waist/hip and waist/thigh ratios; conicity; and log upper-lower skinfold ratio. RESULTS: Three-year tracking of BF varied from 0.79 to 0.90 for one- and from 0.81 to 0.93 for two-occasion measurements showing no apparent sex- or cohort-effects. Three-year tracking of CBFD was lower than that of BF (0.68–0.75), but improved significantly with two-occasion measurements (0.75–0.82). CONCLUSIONS: Within-individual variation is a significant factor in reported low tracking of CBFD in childhood. Estimates of tracking currently in the literature may underestimate the predictive value of CBFD, possibly because this research has used one-occasion measurement. The increased use of two-occasion measurement should significantly improve the tracking of CBFD during development and provide a more realistic understanding of its predictive value.

Abstract —In Project HeartBeat!, a longitudinal study of cardiovascular disease risk factors in healthy children and adolescents, 3 samples of 40, 80, and 182 echocardiograms, respectively, were randomly selected and reread to evaluate intraobserver and interobserver variabilities and comparability between measurements of field echocardiographic technicians and reference readings at Texas Children’s Hospital. Included in the evaluation were 8 M-mode echocardiographic measurements, ie, aortic root diameter, left atrial diameter, and end-diastolic and end-systolic measurements of interventricular septal thickness, left ventricular (LV) diameter, and LV posterior wall thickness; 8 Doppler measurements; and a calculated LV mass. Means and SDs of the differences of the paired measurements were used to assess the relative bias and random error of the measurements. For the intraobserver comparison, means and SDs of the differences were very small, indicating that the echo measurements were performed consistently by each project echo technician. Interobserver comparison showed statistically but not clinically significant differences between the paired readings of end-diastolic septal thickness, end-systolic LV posterior wall thickness, and 5 Doppler measurements. Comparison with reference readings at Texas Children’s Hospital showed significant differences in diastolic LV diameter, systolic septal thickness, and right ventricular ejection time. These differences, however, were minimal with limited clinical significance. Mean differences in LV mass for the corresponding comparisons were –1.82, 4.50, and 0.0013 g, and the SDs were 18.79, 24.16, and 12.35 g, respectively. We conclude that the echocardiographic measurements taken from healthy children in a longitudinal study can be made accurately with acceptable reproducibility.

Background Project HeartBeat! is a longitudinal study of the development of cardiovascular risk factors as growth processes. Patterns of serial change, or trajectories, from ages 8 to 18 years for plasma total cholesterol concentration (TC) and percent body fat illustrate the design and synthetic cohort approach of the study. Methods and Results Six hundred seventy-eight children (49.1% female, 20.1% black) entered the study at ages 8, 11, and 14 years and were followed up with examinations every 4 months for ≤4 years. Multilevel analysis demonstrated trajectories for population mean values of TC and percent body fat in sex-specific synthetic cohorts from ages 8 to 18 years. Polyphasic patterns of change in TC were confirmed, with notable sex differences in age patterns and with minimum mean values of TC of 3.85 mmol/L for females and 3.59 for males. As illustrated by data for males, the approximate 75th percentile values of mean TC ranged from 4.78 mmol/L at its early peak to 4.06 at its late-teen nadir. Percent body fat exhibited a trajectory closely parallel with that for TC only for males and appeared to be unrelated for females. Conclusions The polyphasic trajectory for TC from ages 8 to 18 years differs between females and males, indicates marked age variation in 75th percentile values and, in males only, closely parallels the trajectory for percent body fat. These and other results indicate the value of both follow-up every 4 months across age intervals to detect rapid risk factor change and the synthetic cohort approach for gaining new insights into the dynamics and possible determinants of this change from ages 8 to 18 years.

Author(s): Go, Alan S; Mozaffarian, Dariush; Roger, Veronique L; Benjamin, Emelia J; Berry, Jarett D; Blaha, Michael J; Dai, Shifan; Ford, Earl S; Fox, Caroline S; Franco, Sheila; Fullerton, Heather J; Gillespie, Cathleen; Hailpern, Susan M; Heit, John A; Howard, Virginia J; Huffman, Mark D; Judd, Suzanne E; Kissela, Brett M; Kittner, Steven J; Lackland, Daniel T; Lichtman, Judith H; Lisabeth, Lynda D; Mackey, Rachel H; Magid, David J; Marcus, Gregory M; Marelli, Ariane; Matchar, David B; McGuire, Darren K; Mohler, Emile R; Moy, Claudia S; Mussolino, Michael E; Neumar, Robert W; Nichol, Graham; Pandey, Dilip K; Paynter, Nina P; Reeves, Matthew J; Sorlie, Paul D; Stein, Joel; Towfighi, Amytis; Turan, Tanya N; Virani, Salim S; Wong, Nathan D; Woo, Daniel; Turner, Melanie B; American Heart Association Statistics Committee and Stroke Statistics Subcommittee

Objectives To estimate age-related changes for serum concentration of non−high-density lipoprotein cholesterol (HDL-C), describe non-HDL-C distribution, and examine the prevalence of high non-HDL-C levels in children and adolescents by demographic characteristics and weight status. Study design Data from 7058 participants ages 6-19 years in the 2005-2010 National Health and Nutrition Examination Surveys were analyzed. A high level of non-HDL-C was defined as a non-HDL-C value ≥145mg/dL. Results Locally weighted scatterplot smoothing−smoothed curves showed that non-HDL-C levels increased from 101 mg/dL at age 6 to 111 mg/dL at age 10, decreased to 101 mg/dL at age 14, and then increased to 122 mg/dL at age 19 in non-Hispanic white males. Non-HDL-C levels generally were greater in female than male subjects, lower in non-Hispanic black subjects, and similar in male and slightly lower in female Mexican American subjects, compared with non-Hispanic white subjects. The overall mean was 108 (SE 0.5), and the percentiles were 67 (5th), 74 (10th), 87 (25th), 104 (50th), 123 (75th), 145 (90th), and 158 (95th) mg/dL. Mean and percentiles were greater among age groups 9-11 and 17-19 years than others and greater among non-Hispanic white than non-Hispanic black subjects. The prevalence of high non-HDL-C was 11.8% (95% CI 9.9%-14.0%) and 15.0% (95% CI 12.9%-17.3%) for the age groups 9-11 and 17-19, respectively. It varied significantly by race/ethnicity and overweight/obesity status. Conclusion Non-HDL-C levels vary by age, sex, race/ethnicity, and weight classification status. Evaluation of non-HDL-C in youth should account for its normal physiologic patterns and variations in demographic characteristics and weight classification.