Shumei S. Sun

Systolic Blood Pressure in Childhood Predicts Hypertension and Metabolic Syndrome Later in Life

OBJECTIVE. The goal was to link hypertension and the metabolic syndrome in adulthood directly to blood pressures measured decades earlier for the same individuals as children and to establish criterion values for blood pressure that predict hypertension and the metabolic syndrome later in life. METHODS. We analyzed serial data for 240 men and 253 women in the Fels Longitudinal Study. We derived age- and gender-specific childhood blood pressures that predict hypertension and the metabolic syndrome in adulthood, and we validated these criterion values in a larger sample. RESULTS. Blood pressure diverged between adults with and without the metabolic syndrome beginning at age 5 for boys and age 8 for girls. The odds ratios for developing hypertension at ≥30 years of age ranged from 1.1 for 14- to 18-year-old boys to 3.8 for 5- to 7-year-old boys and from 2.7 for 8- to 13-year-old girls to 4.5 for 5- to 7-year-old girls, if their blood pressure exceeded criterion values at a single examination in childhood. The corresponding odds ratios for the metabolic syndrome, with or without hypertension, ranged from 1.2 for 14- to 18-year-old boys to 2.6 for 8- to 13-year-old boys and from 1.5 for 14- to 18-year-old girls to 3.1 for 5- to 7-year-old girls. The relative risk of adult hypertension ranged from 1.5 to 3.8 for boys and from 1.5 to 4.7 for girls, and that of the metabolic syndrome ranged from 1.1 to 1.8 for boys and from 1.2 to 5.6 for girls. These relative risks varied directly with the number of examinations at which systolic blood pressure exceeded criterion values. CONCLUSION. Children with systolic blood pressures above the criterion values established in this longitudinal study are at increased risk of hypertension and the metabolic syndrome later in life.

Childhood obesity predicts adult metabolic syndrome: the Fels Longitudinal Study.

OBJECTIVES To determine the age of significant divergence in body mass index (BMI) and waist circumference in adults with and without the metabolic syndrome, and to provide age- and sex-specific childhood values that predict adult metabolic syndrome. STUDY DESIGN Part 1 of this study is a retrospective cohort study of 92 men and 59 women (mean age, 51 years) who had metabolic syndrome and 154 randomly selected adults matched for age and sex who did not have the syndrome. Part 2 is a study of predictive accuracy in a validation sample of 743 participants. RESULTS The first appearance of differences between adults with and without metabolic syndrome occurred at ages 8 and 13 for BMI and 6 and 13 for waist circumference in boys and girls, respectively. Odds ratios (ORs) for the metabolic syndrome at 30 years and older ranged from 1.4 to 1.9 across age groups in boys and from 0.8 to 2.8 across age groups in girls if BMI exceeded criterion values in childhood. The corresponding ORs for waist circumference ranged from 2.5 to 31.4 in boys and 1.7 to 2.5 in girls. These ORs increased with the number of examinations. CONCLUSIONS Children with BMI and waist circumference values exceeding the established criterion values are at increased risk for the adult metabolic syndrome.

Do Changes in Body Mass Index Percentile Reflect Changes in Body Composition in Children? Data From the Fels Longitudinal Study

OBJECTIVE. Our aim was to examine the degree to which changes in BMI percentile reflect changes in body fat and lean body mass during childhood and how age and gender affect these relationships. METHODS. This analysis used serial data on 494 white boys and girls who were aged 8 to 18 years and participating in the Fels Longitudinal Study (total 2319 observations). Total body fat (TBF), total body fat-free mass (FFM), and percentage of body fat (%BF) were determined by hydrodensitometry, and then BMI was partitioned into its fat and fat-free components: fat mass index (FMI) and FFM index (FFMI). We calculated predicted changes (Δ) in FMI, FFMI, and %BF for each 10-unit increase in BMI percentile using mixed-effects models. RESULTS. FFMI had a linear relationship with BMI percentile, whereas FMI and %BF tended to increase dramatically only at higher BMI percentiles. Gender and age had significant effects on the relationship between BMI percentile and FFMI, FMI, and %BF. Predicted Δ%BF for boys 13 to 18 years of age was negative, suggesting loss of relative fatness for each 10-unit increase in BMI percentile. CONCLUSIONS. In this longitudinal study of white children, FFMI consistently increased with BMI percentile, whereas FMI and %BF had more complicated relationships with BMI percentile depending on gender, age, and whether BMI percentile was high or low. Our results suggest that BMI percentile changes may not accurately reflect changes in adiposity in children over time, particularly among male adolescents and children of lower BMI.

Anatomical Patterning of Visceral Adipose Tissue: Race, Sex, and Age Variation

Objective: We tested sex, race, and age differences in the patterning of visceral adipose tissue (VAT) and subcutaneous adipose tissue.

Lipids, lipoproteins, lifestyle, adiposity and fat-free mass during middle age: the Fels Longitudinal Study.

Introduction:Although lipid profiles tend to worsen with age, it is not fully known if such age-related changes are influenced primarily by body composition and lifestyle or by other aspects of aging.Objective:We investigated the extent to which the fat and fat-free components of body mass index (BMI) and lifestyle factors influence patterns of change in lipids independent of age.Design:Serial data were analyzed using sex-specific longitudinal models. These models use serial data from individuals to assume a general pattern of change over time, while allowing baseline age and the rate of change to vary among individuals.Subjects:Serial data were obtained from 940 examinations of 269 healthy white participants (126 men, 143 women), aged 40–60 years, in the Fels Longitudinal Study.Measurements:Measurements included age, the fat (FMI) and fat-free mass (FFMI) components of BMI, high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C), triglycerides (TG), total cholesterol (TC), fasting glucose and insulin, physical activity, alcohol use and smoking, and womens menopausal status and estrogen use.Results:In both sexes, increased FMI was significantly associated with increased LDL-C, TG and TC, and decreased HDL-C. Increased FFMI was significantly related to decreased HDL-C and increased TG. Independent age effects remained significant only for LDL-C and TC in men and TC in women. Increased insulin was significantly related to increased TG in women. Moderate alcohol consumption was associated with higher HDL-C in men. Physical activity lowered male LDL-C and TC levels, and increased female HDL-C levels. Menopause was associated with increases in LDL-C. Premenopausal women not using estrogen had significantly lower HDL-C, TG, and TC than postmenopausal women taking estrogen.Conclusions:(1) Age is an important independent predictor for LDL-C and TC in men, and TC in women, but it is not as influential as body composition and lifestyle on HDL-C and TG in men and women, and LDL-C in women. (2) Increasing FMI is the major contributor to elevated TC, LDL-C and TG levels, and decreased HDL-C levels in men and women. (3) FFMI significantly influences HDL and TG levels in both sexes. (4) Maintaining a lower BMI via a reduced fat component may be more beneficial in lowering CVD risks than other factors.

Predictive Ability of Childhood Metabolic Components for Adult Metabolic Syndrome and Type 2 Diabetes

OBJECTIVE To estimate sensitivity, specificity, and positive and negative predictive values of components of the metabolic syndrome (MetS) during childhood for MetS and type 2 diabetes (T2D) in adulthood. STUDY DESIGN Data from 3 major studies-the Fels Longitudinal Study, the Muscatine Study, and the Princeton Follow-up Study-were combined to examine how thresholds of metabolic components during childhood determine adult MetS and T2D. Available metabolic components examined in the 1789 subjects included high-density lipoprotein, triglyceride levels, glucose, and percentiles for body mass index, waist circumference, triglycerides, and systolic and diastolic blood pressures. Sensitivity, specificity, and positive and negative predictive values for a refined set of component threshold values were examined individually and in combination. RESULTS Sensitivity and positive predictive values remained low for adult MetS and T2D for individual components. However, specificity and negative predictive values were fairly high for MetS and exceptionally so for T2D. In combination, having 1 or more of the components showed the highest sensitivity over any individual component and high negative predictive value. Overall, specificity and negative predictive values remained high whether considering individual or combined components for T2D. CONCLUSIONS Sensitivity and positive predictive values on the basis of childhood measures remained relatively low, but specificity and negative predictive values were consistently higher, especially for T2D. This indicates that these components, when examined during childhood, may provide a useful screening approach to identifying children not at risk so that further attention can be focused on those who may be in need of future intervention.

Stability of the Factor Structure of the Metabolic Syndrome across Pubertal Development: Confirmatory Factor Analyses of Three Alternative Models

OBJECTIVE To test the fit and stability of 3 alternative models of the metabolic syndromes factor structure across 3 developmental stages. STUDY DESIGN With data from the Fels Longitudinal Study, confirmatory factor analyses tested 3 alternative models of the factor structure underlying relationships among 8 metabolic syndrome-associated risks. Models tested were a 1-factor model (A), a 4-factor model (B), and a second-order latent factor model (C). Developmental stages assessed were prepuberty (ages 8-10), puberty (ages 11-15), and postpuberty (ages 16-20). RESULTS Convergence was achieved for all developmental stages for model A, but the fit was poor throughout (root mean square error of approximation > 0.1). Standardized factor loadings for waist circumference and body mass index were much stronger than those for fasting insulin at all 3 time points. Although prepuberty and postpuberty models converged for models B and C, each model had problems with Heywood cases. The puberty model did not converge for either model B or C. CONCLUSIONS The hypothetical structures commonly used to support the metabolic syndrome concept do not provide adequate fit in a pediatric sample and may be variable by maturation stage. A components-based approach to cardiovascular risk reduction, with emphasis on obesity prevention and control, may be a more appropriate clinical strategy for children and youth than a syndromic approach.

Serial Childhood BMI and Associations With Adult Hypertension and Obesity: The Fels Longitudinal Study

Previous studies estimated critical periods of childhood BMI growth and linked these events to adult adiposity and cardiovascular health. We expand upon both results to link childhood BMI growth patterns with adult blood pressure (BP). Data from male and female participants in the Fels Longitudinal Study (FLS) were used to estimate childhood BMI growth curves, from which we isolate ages of childhood BMI divergence based upon adult BMI and BP measurements. Repeated measure analysis of variances models were used to estimate BMI growth curves from age 2 to age 17.5 based on both adult BMI (< 25 kg/m2 or ≥ 25 kg/m2) and adult BP (< 120 mm Hg or ≥ 120 mm Hg for systolic BP (SBP); < 80 mm Hg or ≥ 80 mm Hg for diastolic BP (DBP)). Participants with lower body weight throughout childhood had lower SBP and DBP in early adulthood. Any relationships between childhood adiposity and adult body weight and BP disappeared by age 60. These results were independent of adult BMI and were observed in both men and women. Increased adult BP has its genesis in part from increased childhood BMI.

Secular trends in body composition for children and young adults: the Fels Longitudinal Study.

To determine secular trends by birth decade in body mass index (BMI), waist circumference/height (W/Ht), percent body fat (PBF), and fat‐free mass adjusted for height squared (FFM/Ht2) in children and adolescents aged 8–18 years.

Patterns of Change in Cardiometabolic Risk Factors Associated with the Metabolic Syndrome among Children and Adolescents: The Fels Longitudinal Study

OBJECTIVES To examine the patterns of change in cardiometabolic risk factors associated with the metabolic syndrome in children and adolescents between the ages of 8 to 19 years. STUDY DESIGN Data of children and adolescents who participated in the Fels Longitudinal Study were analyzed. Body mass index, waist circumference, fasting insulin, fasting glucose, triglycerides, high-density lipoprotein cholesterol, systolic blood pressure, and diastolic blood pressure were assessed annually with a standardized protocol. RESULTS The proportion of participants having at least 1 change between states of high and normal risk ranged from of 11.0% for body mass index to 30.4% for triglycerides. Youth in the high-risk category at baseline had a higher proportion having changed their status for all risk factors (all P < .05) except waist circumference compared with those in the normal-risk category. There were significant time effects for all risk factors (all P < .01) except fasting glucose and triglyceride levels in metric scores, but insignificant time effects for all risk factors in Z-scores in growth curve analyses. CONCLUSIONS The cardiometabolic risk factors associated with the MetS were relatively stable among white children and adolescents in the normal risk category. Changes in status were common if the risk factor was elevated.