Adiposity in Childhood Is Related to C‐Reactive Protein and Adiponectin in Young Adulthood: From the Bogalusa Heart Study

To determine the association between cardiovascular (CV) risk factors in childhood and high‐sensitivity C‐reactive protein (hsCRP) and adiponectin in adulthood, 835 eligible white and African‐American young adult subjects (age range 24–42 years, average 34 years, 43% men, 31% African Americans) who had CV risk‐factor variable data from their childhood (20 years earlier, age range 5–18 years, average 14 years) were selected. Stepwise linear regression models revealed that mean logarithmic hsCRP level in adulthood was 0.02 greater with every increase of 1 mm in skinfold thickness in childhood, 0.25 greater for African Americans than whites, 0.36 greater for girls than boys, and 0.15 greater for every unit increase in BMI z score. Mean logarithmic adiponectin level in adulthood was 0.36 greater for girls than boys, 0.22 greater for whites than African Americans, and 0.01 less with every increase of 1 mm of childhood skinfold thickness. Seventy participants (8%) were overweight or obese in their childhood, and 64 of these (91%) remained obese in their young adulthood. In conclusion, childhood adiposity and African‐American race were associated with higher hsCRP and lower adiponectin levels in their adulthood. Skinfold thickness and BMI z score in childhood were the main obesity determinants for higher hsCRP and lower adiponectin levels in young adulthood.     

Adiponectin and ghrelin levels and body size in normoglycemic Filipino, African-American, and white women

Objective: Prior studies have reported ethnic differences in adiponectin and ghrelin, but few have assessed the role of body size in normoglycemic women. We compared fasting adiponectin and ghrelin concentrations in normoglycemic 40‐ to 80‐year‐old Filipino, African‐American, and white women. Methods: Participants included women from the Rancho Bernardo Study (n = 143), the University of California‐San Diego Filipino Women's Health Study (n = 136), and the Health Assessment Study of African‐American Women (n = 212). A 2‐hour oral glucose tolerance test was administered; glucose, insulin, lipid, and anthropometric measurements were obtained. Fasting adiponectin and ghrelin were measured by radioimmunoassay. Results: Whites and Filipinas had similar BMI (23.7 and 24.3 kg/m², respectively), waist girth (75.6 and 77.2 cm, respectively), and total body fat (27.4 and 28.5%, respectively); African‐Americans had significantly larger BMI (28.8 kg/m²), waist girth (86.3 cm), and body fat (39.6%, p < 0.0001). Adiponectin was lower in Filipinas (8.90 µg/mL) and African‐Americans (9.67 µg/mL) compared with whites (15.6 µg/mL, p < 0.001) after adjusting for age, homeostasis model assessment of insulin resistance (HOMA‐IR), and waist‐to‐hip ratio. Compared with whites, Filipinas (β = ?5.06, p < 0.0001) and African‐Americans (β = ?6.85, p < 0.0001) had significantly lower adiponectin levels after adjusting for age, waist‐to‐hip ratio, HOMA‐IR, triglycerides, high‐density lipoprotein (HDL) cholesterol, exercise, and alcohol use. Ghrelin was significantly lower in Filipinas compared with African‐Americans (1146.9 vs. 1412.2 pg/mL, p < 0.001), and this observation persisted in multivariable analysis (β = ?245.4, p < 0.0001). Ghrelin levels did not differ between whites (1356.9 pg/mL) and either ethnic group. Discussion: Normoglycemic Filipino and African‐American women had significantly lower adiponectin concentrations than white women, and Filipinas had lower ghrelin levels than African‐Americans, independently of body size or indices of insulin resistance or lipids.     

Adolescent Sex Differences in Adiponectin Are Conditional on Pubertal Development and Adiposity

Objective: Adiponectin is an adipose tissue protein with important insulin‐sensitizing, anti‐inflammatory, and cardioprotective properties but is paradoxically lower in obese individuals. Sex differences in adiponectin have been reported in adults and adolescents but not in prepubertal children. In this study, we hypothesized that sex differences in adiponectin would develop during puberty and would be influenced by level of adiposity. Research Methods and Procedures: Adiponectin levels were measured in 1196 white and African‐American adolescents. Insulin resistance was estimated using the homeostasis model (HOMA‐IR). Demographic, developmental, and metabolic variables, including interactions with adiposity measurements, were evaluated for independent relationships with adiponectin levels. Results: Overall, adiponectin levels varied significantly by sex, race, adiposity, and puberty stage. Significant sex differences in adiponectin developed after the onset of puberty, particularly in lean adolescents. Adolescent boys had lower adiponectin levels in post‐puberty compared with pre‐puberty (p = 0.01) and had lower levels than girls in both puberty and post‐puberty (both p < 0.001), after adjusting for race, BMI z‐score, and natural logarithm‐(HOMA‐IR). Sex differences were also conditional on adiposity level, with significant sex differences among lean (p < 0.001) but not among non‐lean (p = 0.16) adolescents. Adiponectin levels in girls decreased more with increasing adiposity than in boys (p = 0.004), but only marginally so after standardizing for girls’ higher mean adiponectin level (p = 0.11). Discussion: Sex differences in adiponectin are dependent on both puberty stage and adiposity in adolescents, such that by post‐puberty, non‐lean boys exhibit the lowest levels of adiponectin.     

Insulin Sensitivity in African‐American and White Women: Association With Inflammation

Whether the contribution of inflammation to risk for chronic metabolic disease differs with ethnicity is not known. The objective of this study was to determine: (i) whether ethnic differences exist in markers of inflammation and (ii) whether lower insulin sensitivity among African Americans vs. whites is due to greater inflammatory status. Subjects were African‐American (n = 108) and white (n = 105) women, BMI 27–30 kg/m². Insulin sensitivity was assessed with intravenous glucose tolerance test and minimal modeling; fat distribution with computed tomography; body composition with dual‐energy X‐ray absorptiometry; markers of inflammation (tumor necrosis factor (TNF)‐α, soluble tumor necrosis factor receptor (sTNFR)‐1, sTNFR‐2, C‐reactive protein (CRP), and interleukin (IL)‐6) with enzyme‐linked immunosorbent assay (ELISA). Whites had greater intra‐abdominal adipose tissue (IAAT), insulin sensitivity, and concentrations of TNF‐α, sTNFR‐1, and sTNFR‐2 than African Americans. Greater TNF‐α in whites vs. African Americans was attributed to greater IAAT in whites. Among whites, but not African Americans, CRP was independently and inversely associated with insulin sensitivity, after adjusting for IAAT (r = ?0.29 P < 0.05, and r = ?0.13 P = 0.53, respectively). Insulin sensitivity remained lower in African Americans after adjusting for CRP (P < 0.001). In conclusion, greater IAAT among whites may be associated with greater inflammation. Insulin sensitivity was lower among African Americans, independent of obesity, fat distribution, and inflammation.     

Relationship between Plasma Adiponectin Levels and Metabolic Risk Profiles in Taiwanese Children

Objective: Adiponectin, a novel adipokine with antiinflammatory and insulin‐sensitizing properties, has an important role in glucose metabolism and is negatively correlated with body fat amount in adults. The purpose of this study was to evaluate the association of plasma adiponectin level with metabolic risk profiles and insulin resistance status among Taiwanese children. Research Methods and Procedures: We enrolled 1248 children (608 boys and 640 girls) to ascertain their demographic, anthropometric, and cardiovascular risk factors distribution in Taipei. We measured plasma insulin, adiponectin, and leptin levels by radioimmunoassay (Linco Research Inc, St. Charles, MO). We calculated an insulin resistance index (IRI) using the Homeostasis Model Assessment model and also calculated an insulin resistance syndrome (IRS) summary score for each individual by adding the quartile ranks from the distribution of systolic blood pressure, serum triglyceride, high‐density lipoprotein‐cholesterol (HDL‐C) (inverse), and insulin levels. Results: In general, the boys had larger BMI, higher systolic blood pressure, serum total cholesterol, and triglyceride, and lower plasma leptin and adiponectin levels than girls. Plasma adiponectin levels were correlated negatively with BMI, leptin, insulin, IRI, and IRS summary score but positively correlated with HDL‐C in both boys and girls. In multivariate regression analyses, adiponectin was negatively associated with insulin (girls only), IRI (girls only), and IRS score, and positively associated with HDL‐C in both genders even after adjusting for age, BMI, plasma leptin level, and other potential confounders. Discussion: These data suggest that plasma adiponectin levels were negatively associated with metabolic risk profiles that may have played a protective role in the development of insulin resistance among Taiwanese school children.     

Baseline Correlates of Insulin Resistance in Inner City High‐BMI African‐American Children

To characterize the influence of diet‐, physical activity–, and self‐esteem‐related factors on insulin resistance in 8–10‐year‐old African‐American (AA) children with BMI greater than the 85th percentile who were screened to participate in a community‐based type 2 diabetes mellitus (T2DM) prevention trial. In 165 subjects, fasting glucose‐ and insulin‐derived values for homeostasis model assessment of insulin resistance (HOMA‐IR) assessed insulin resistance. Body fatness was calculated following bioelectrical impedance analysis, and fitness was measured using laps from a 20‐m shuttle run. Child questionnaires assessed physical activity, dietary habits, and self‐esteem. Pubertal staging was assessed using serum levels of sex hormones. Parent questionnaires assessed family demographics, family health, and family food and physical activity habits. Girls had significantly higher percent body fat but similar anthropometric measures compared with boys, whereas boys spent more time in high‐intensity activities than girls. Scores for self‐perceived behavior were higher for girls than for boys; and girls desired a more slender body. Girls had significantly higher insulin resistance (HOMA‐IR), compared with boys (P < 0.01). Adjusting for age, sex, pubertal stage, socioeconomic index (SE index), and family history of diabetes, multivariate regression analysis showed that children with higher waist circumference (WC) (P < 0.001) and lower Harter's scholastic competence (SC) scale (P = 0.044) had higher insulin resistance. WC and selected self‐esteem parameters predicted insulin resistance in high‐BMI AA children. The risk of T2DM may be reduced in these children by targeting these factors.     

Sex‐Specific Fat Distribution Is Not Linear Across Pubertal Groups in a Multiethnic Study

Objective: To investigate sexual dimorphism and race differences in fat distribution (android/gynoid) before and during puberty. Research Methods and Procedures: Fat distribution was measured by skinfold thickness and DXA in healthy African‐American, Asian, and white subjects (n = 920), divided into pre‐, early, and late pubertal groups. Results: Gynoid fat masses adjusted for covariates were lower in late pubertal compared with prepubertal boys, but were not consistently greater in late pubertal compared with prepubertal girls. Progression of sex‐specific fat distribution with increasing maturation was present in Asians only. Among African‐American and white subjects, early pubertal boys had greater gynoid fat mass compared with the prepubertal group, whereas early pubertal girls had less gynoid fat mass compared with the prepubertal group. Sexual dimorphism in fat distribution was present in all pubertal groups, except among whites at early puberty. Among girls, Asians had lower gynoid fat than whites and African Americans in all pubertal groups. Among boys, Asians had less gynoid fat by DXA in early puberty and late puberty. Discussion: Comparison among races demonstrated differences in sexual dimorphism and sex‐specific fat distribution with progression in pubertal group. However, in all race groups, the fat distribution of late pubertal boys was more “male” or “android” than prepubertal boys, but late pubertal girls did not differ consistently from prepubertal girls. These findings suggested that the greater sexual dimorphism of fat distribution in late puberty compared with prepuberty may be attributable to larger changes in boys with smaller changes in girls.     

Body mass, DRD4, physical activity, sedentary behavior, and family socioeconomic status: the add health study

Objective: To investigate the joint role of the 48‐base pair repeat polymorphism of the dopamine receptor 4 gene (DRD4) and environmental factors in body mass variation among an ethnically diverse sample of U.S. adolescents and young adults. Research Methods and Procedures: Approximately 2600 adolescent and young adults in the National Longitudinal Study of Adolescent Health (Add Health) who provided DNA measures and measures of height and weight were included in the analysis. Mixed regression modeling was used to investigate the effects of the 7R/7R and any5R variants in the DRD4 gene simultaneously with the effects of physical activity (PA), sedentary behavior (SB), and family socioeconomic status (SES) on body mass variation. European Americans, African Americans, and Hispanic Americans were modeled separately. Results and Discussion: Both the 7R/7R and any5R genotypes of the DRD4 gene were associated with age‐ and sex‐specific BMI percentile score (BMI‐P) based on the Centers for Disease Control and Prevention/National Center for Health Statistics 2000 reference curves among African Americans and only among African Americans (N = 413) 20 years old or younger. Neither genetic variants are associated with the BMI measure among white (N = 1386) and Hispanic‐American (N = 331) adolescents. The presence of the 7R/7R genotype was associated with a reduction of 15.1 in BMI percentile (p = 0.005), and the presence of any5R was associated with an increase of 15.5 in BMI percentile (p = 0.003), after adjusting for PA, SB, and family SES. Neither PA nor SB as measured in Add Health is importantly associated with BMI‐P, suggesting a complex relationship between body mass and PA/SB among adolescents and young adults. Family SES is negatively related to BMI‐P in the European‐American sample.     

Variants in the Adiponectin Gene and Serum Adiponectin: The Coronary Artery Development in Young Adults (CARDIA) Study

Circulating adiponectin is involved in the atherosclerotic process and has been associated with cardiovascular disease as well as obesity, insulin resistance, metabolic syndrome, and type 2 diabetes. The adiponectin gene (ADIPOQ) encodes the circulating protein adiponectin and affects its expression. Only a small proportion of all known ADIPOQ polymorphisms have been investigated in relation to circulating adiponectin concentrations. Using data from 3,355 African‐American and white men and women aged 33–45 at the year 15 examination from the Coronary Artery Development in Young Adults (CARDIA) Study the association between 10 single‐nucleotide polymorphisms (SNPs) within ADIPOQ and serum adiponectin was examined using linear regression. SNPs were chosen based on a tagSNP approach. Models were stratified by self‐reported race to control for population stratification, and Bonferroni corrected for multiple comparisons. ADIPOQ SNPs rs17300539 (P < 0.0001), rs182052 (P = 0.0013), rs822393 (P = 0.0005), rs9882205 (P = 0.0001), and rs3774261 (P = 0.0001) were strongly associated with serum adiponectin concentrations in whites. In general, there was a dose‐response relationship of adjusted mean adiponectin concentrations across genotypes. Only one SNP, rs17300539 was marginally associated with serum adiponectin concentrations (P = 0.0087) in African Americans. Significant interactions were found between waist and rs182052 (P = 0.0029) and between rs9882505 and smoking (P = 0.001) in whites. Many ADIPOQ SNPs have not yet been examined, and additional studies are needed to determine whether these may be functional variants.     

Ethnic Differences in Visceral Adipose Tissue and Type 2 Diabetes: Filipino,African‐American,and White Women

Objective: To compare ethnic differences in visceral adipose tissue (VAT), assessed by computed tomography, and type 2 diabetes risk among 55‐ to 80‐year‐old Filipino, African‐American, and white women without known cardiovascular disease. Research Methods and Procedures: Subjects were participants in the Rancho Bernardo Study (n = 196), the Filipino Women's Health Study (n = 181), and the Health Assessment Study of African‐American Women (n = 193). Glucose and anthropometric measurements were assessed between 1995 and 2002. Results: African‐American women had significantly higher age‐adjusted BMI (29.7 kg/m²) and waist girth (88.1 cm) compared with Filipino (BMI, 25.5 kg/m²; waist girth, 81.9 cm) or white (BMI: 26.0 kg/m²; waist girth: 80.7 cm) women. However, VAT was significantly higher among Filipino (69.1 cm³) compared with white (62.3 cm³; p = 0.037) or African‐American (57.5 cm³, p < 0.001) women. VAT correlated better with BMI (r = 0.69) and waist (r = 0.77) in whites, compared with Filipino (r = 0.42; r = 0.59) or African‐American (r = 0.50; r = 0.56) women. Age‐adjusted type 2 diabetes prevalence was significantly higher in Filipinas (32.1%) than in white (5.8%) or African‐American (12.1%) women. Filipinas had higher type 2 diabetes risk compared with African Americans [adjusted odds ratio, 2.30; 95% confidence interval (CI), 1.09 to 4.86] or whites (adjusted odds ratio, 7.51; 95% CI, 2.51 to 22.5) after adjusting for age, VAT, exercise, education, and alcohol intake. Discussion: VAT was highest among Filipinas despite similar BMI and waist circumference as whites. BMI and waist circumference were weaker estimates of VAT in Filipino and African‐American women than in whites. Type 2 diabetes prevalence was highest among Filipino women at every level of VAT, but VAT did not explain their elevated type 2 diabetes risk.     

Plasma Adiponectin Levels in High Risk African‐Americans with Normal Glucose Tolerance,Impaired Glucose Tolerance,and Type 2 Diabetes**

Objective: We studied plasma adiponectin, insulin sensitivity, and insulin secretion before and after oral glucose challenge in normal glucose tolerant, impaired glucose tolerant, and type 2 diabetic first degree relatives of African‐American patients with type 2 diabetes. Research Methods and Procedures: We studied 19 subjects with normal glucose tolerance (NGT), 8 with impaired glucose tolerance (IGT), and 14 with type 2 diabetes. Serum glucose, insulin, C‐peptide, and plasma adiponectin levels were measured before and 2 hours after oral glucose tolerance test. Homeostasis model assessment‐insulin resistance index (HOMA‐IR) and HOMA‐β cell function were calculated in each subject using HOMA. We empirically defined insulin sensitivity as HOMA‐IR < 2.68 and insulin resistance as HOMA‐IR > 2.68. Results: Subjects with IGT and type 2 diabetes were more insulin resistant (as assessed by HOMA‐IR) when compared with NGT subjects. Mean plasma fasting adiponectin levels were significantly lower in the type 2 diabetes group when compared with NGT and IGT groups. Plasma adiponectin levels were 2‐fold greater (11.09 ± 4.98 vs. 6.42 ± 3.3811 μg/mL) in insulin‐sensitive (HOMA‐IR, 1.74 ± 0.65) than in insulin‐resistant (HOMA‐IR, 5.12 ± 2.14) NGT subjects. Mean plasma adiponectin levels were significantly lower in the glucose tolerant, insulin‐resistant subjects than in the insulin sensitive NGT subjects and were comparable with those of the patients with newly diagnosed type 2 diabetes. We found significant inverse relationships of adiponectin with HOMA‐IR (r = ?0.502, p = 0.046) and with HOMA‐β cell function (r = ?0.498, p = 0.042) but not with the percentage body fat (r = ?0.368, p = 0.063), serum glucose, BMI, age, and glycosylated hemoglobin A1C (%A1C). Discussion: In summary, we found that plasma adiponectin levels were significantly lower in insulin‐resistant, non‐diabetic first degree relatives of African‐American patients with type 2 diabetes and in those with newly diagnosed type 2 diabetes. We conclude that a decreased plasma adiponectin and insulin resistance coexist in a genetically prone subset of first degree African‐American relatives before development of IGT and type 2 diabetes.     

Comparison of Regional Fat Distribution and Health Risk Factors in Middle‐Aged White and African American Women: The Healthy Transitions Study

Objective: Both ethnicity and menopause appear to influence intra‐abdominal fat distribution. This study evaluated intra‐abdominal fat distribution and obesity‐related health risks in perimenopausal white and African American women. Research Methods and Procedures: Baseline data from a longitudinal study of changes in body composition and energy balance during menopause are reported. Healthy women (55 African Americans and 103 whites) who were on no medication and had at least five menstrual cycles in the previous 6 months were recruited. Body composition was assessed by DXA, and visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed by computed tomography scan. SAT was divided into deep and superficial layers demarcated by the fascia superficialis. Results: African American women were slightly younger (46.7 ± 0.2 vs. 47.7 ± 0.2 years, p = 0.002) and fatter (42.4% ± 1.0% vs. 39.4% ± 0.8% body fat, p = 0.02) than white women. In unadjusted data, African Americans had significantly more total abdominal fat and total, deep, and superficial SAT than whites. After adjustment for percent body fat and age, only total and superficial SAT remained significantly higher in African Americans. VAT although slightly less in African American women, did not differ significantly by race. In multiple regression analysis, VAT was the strongest predictor of serum lipids, glucose, and insulin in women of both races, although superficial SAT was significantly associated with fasting glucose in whites. Conclusions: Middle‐aged African American women have larger SAT depots, adjusted for total body fatness, but do not differ from white women with regard to VAT. The complexity of the relationship between abdominal fat and metabolic risk is increased by ethnic differences in such associations.     

A genome-wide scan of loci linked to serum adiponectin in two populations of African descent

Objective: The objectives were to identify quantitative trait loci linked to serum adiponectin concentration and to estimate heritability in two populations of African descent. Research Methods and Procedures: We conducted a genome scan for serum adiponectin concentration in two populations of African descent. Genome‐wide microsatelitte markers were typed in an African‐American population consisting of 203 families from the Chicago area and in a Nigerian Yoruba population consisting of 146 families. Linkage analysis was performed to identify loci. Variance component model was used to estimate heritability. Results: Estimates of heritability adjusted for age, gender, and BMI were 0.45 and 0.70 for the African‐American and Nigerian families, respectively. In both populations, adiponectin was significantly negatively correlated with BMI, height, and weight. After adjusting for age, gender, and BMI, we found evidence of genetic linkage to adiponectin on chromosomes 11 [limit of detection (LOD) score = 2.89] and 17 (LOD score = 1.35) in the Nigerian sample. Among the African‐Americans, we found genetic linkage on chromosomes 2 (LOD score = 1.82), 4 (LOD score = 2.12), and 11 (LOD score = 2.33). Analysis based on combined data yielded a maximum LOD score of 3.21 on chromosome 11. Discussion: Consistency of the finding on chromosome 11 suggests that this region is likely to be involved in regulation of adiponectin, either through a primary influence on hormone levels or through pathways influencing body composition. These results suggest that adiponectin could be a potential therapeutic target for obesity.     

Anti‐lipolytic Effects of Insulin in African American and White Prepubertal Boys

Objective: Relative to whites, African Americans have lower circulating triglycerides (TG) and greater highdensity lipoprotein cholesterol. The metabolic basis for this difference is not known. This study was conducted to test the hypothesis that insulin‐induced suppression of free fatty acids (FFA) results in lower serum TG in African American versus white prepubertal children. Research Methods and Procedures: Insulin, FFA, and TG were determined at baseline and during a frequently sampled, intravenous glucose tolerance test in eight African American and eight white prepubertal males pair‐matched for whole‐body insulin sensitivity. Results: Baseline TG was lower in African Americans (0.43 ± 0.10 vs. 0.79 ± 0.37 mM/L; mean ± SD; p < 0.01). African Americans had higher peak insulin (218 ± 102 vs. 100 ± 30 pM/L; mean ± SD; p < 0.01) and a greater acute insulin response (9282 ± 4272 vs. 4230 ± 1326 pM/L × 10 minutes; mean ± SD; p < 0.05). FFA and TG values determined at the FFA nadir were lower in African Americans (0.26 ± 0.02 vs. 0.30 ± 0.03 mEq/L; mean ± SD; p < 0.01 for FFA nadir and 0.49 ± 0.07 vs. 0.77 ± 0.33 mM/L; mean ± SD; p < 0.05 for TG). Among all subjects, FFA nadir was correlated with peak insulin (r = ?0.54; p < 0.05). After adjusting for FFA nadir, neither baseline nor postchallenge TG differed with ethnicity (p = 0.073 and 0.192, respectively). The ethnic difference in FFA nadir disappeared after adjusting for peak insulin (p = 0.073). Discussion: These data suggest that hyperinsulinemiainduced suppression of FFA among African Americans is a determinant of lower TG in this group.     

Racial Differences in the Tracking of Childhood BMI to Adulthood

Objective: The possibility that there are racial differences in the patterns of BMI (kilograms per meter squared) change throughout life has not been examined. For example, the high prevalence of obesity among black women could result from a higher prevalence of obesity among black girls or because normal‐weight black girls experience larger BMI increases in adolescence or adulthood than do their white counterparts. Therefore, we examined the tracking of childhood BMI into adulthood in a biracial (36% black) sample. Research Methods and Procedures: Five‐ to 14‐year‐old children (2392) were followed for (mean) 17 years. Childhood overweight was defined as BMI ≥ 95th percentile, and adult obesity was defined as BMI ≥ 30 kg/m². Results: The tracking of childhood BMI differed between whites and blacks. Among overweight children, 65% of white girls vs. 84% of black girls became obese adults, and predictive values among boys were 71% (whites) vs. 82% (blacks). These racial differences reflected contrasting patterns in the rate of BMI change. Although the initial BMI of black children was not higher than that of white children, BMI increases with age were larger among black girls and overweight black boys than among their white counterparts. In contrast, relatively thin (BMI < 50th percentile) white boys were more likely to become overweight adults than were their black counterparts. Discussion: These findings emphasize the black/white differences in BMI changes with age. Because of the adult health consequences of childhood‐onset obesity, early prevention should be given additional emphasis.     

Physical activity correlates in adolescent girls who differ by weight status

Objective: This study compared correlates of physical activity (PA) among African‐American and white girls of different weight groups to guide future interventions. Research Methods and Procedures: Participants were 1015 girls (mean age, 14.6 years; 45% African‐American) from 12 high schools in South Carolina who served as control subjects for a school‐based intervention. Post‐intervention measures obtained at the end of ninth grade were used. PA was measured using the Three‐Day PA Recall, and a questionnaire measured social‐cognitive and environmental variables thought to mediate PA. Height and weight were measured, and BMI was calculated. Girls were stratified by race and categorized into three groups, based on BMI percentiles for girls from CDC growth charts: normal (BMI < 85th percentile), at risk (BMI, 85th to 94th percentile), and overweight (BMI ≥ 95th percentile). Girls were further divided into active and low‐active groups, based on a vigorous PA standard (average of one or more 30‐minute blocks per day per 3‐day period). Mixed‐model ANOVA was used to compare factors among groups, treating school as a random effect Results: None of the social‐cognitive or environmental variables differed by weight status for African‐American or white girls. Perceived behavioral control and sports team participation were significantly higher in girls who were more active, regardless of weight or race group. In general, social‐cognitive variables seem to be more related to activity in white girls, whereas environmental factors seem more related to activity in African‐American girls. Discussion: PA interventions should be tailored to the unique needs of girls based on PA levels and race, rather than on weight status alone.     

Weight Status in Childhood as a Predictor of Becoming Overweight or Hypertensive in Early Adulthood**

Objective: To assess the extent to which weight status in childhood or adolescence predicts becoming overweight or hypertensive by young adulthood. Research Methods and Procedures: We conducted a prospective study of 314 children, who were 8 to 15 years old at baseline, and were followed up 8 to 12 years later. Weight, height, and blood pressure were measured by trained research staff. Incident overweight was defined as BMI ≥ 25 kg/m² among participants who had not been overweight as children. Results: More male subjects (48.3%) than female subjects (23.5%) became overweight or obese between their first childhood visit and the young adult follow‐up (p < 0.001). Being in the upper one half of the normal weight range (i.e., BMI between the 50th and 84th percentiles for age and gender in childhood) was a good predictor of becoming overweight as a young adult. Compared with children with a BMI <50th percentile, girls and boys between the 50th and 74th percentiles of BMI were ～5 times more likely [boys, odds ratio (OR) = 5.3, p = 0.002; girls, OR = 4.8, p = 0.07] and those with a BMI between the 75th and 84th percentiles were up to 20 times more likely (boys, OR = 4.3, p = 0.02; girls, OR = 20.2, p = 0.001) to become overweight. The incidence of high blood pressure was greater among the male subjects (12.3% vs. 1.9%). Compared with boys who had childhood BMI below the 75th percentile, boys between the 75th and 85th percentiles of BMI as children were four times more likely (OR = 3.6) and those at above the 85th percentile were five times more likely (OR = 5.1) to become hypertensive. Discussion: High normal weight status in childhood predicted becoming overweight or obese as an adult. Also, among the boys, elevated BMI in childhood predicted risk of hypertension in young adulthood.     

Relation of Leptin to Insulin Resistance Syndrome in Children

Objectives: To examine the relation of leptin to insulin resistance, as measured by euglycemic insulin clamp, and insulin resistance syndrome factors in thin and heavy children. Research Methods and Procedures: Anthropometrics, insulin, blood pressure, and leptin were measured in 342 11‐ to 14‐year‐old children (189 boys, 153 girls, 272 white, 70 black). Insulin sensitivity (M) was determined by milligrams glucose uptake per kilogram per minute and expressed as M/lean body mass (M_lbm). Children were divided by median BMI (boys = 20.5 kg/m²; girls = 21.4 kg/m²) into below‐median (thin) and above‐median (heavy) groups. Correlation coefficients between log‐leptin and components of insulin resistance syndrome were adjusted for Tanner stage, gender, and race. Results: BMI was related to leptin in boys (r = 0.70, p < 0.001) and girls (r = 0.75, p < 0.001). Leptin was higher in girls than boys (32.6 vs. 12.3 ng/mL, p = 0.0001). Leptin levels increased in girls and decreased in boys during puberty, paralleling the changes in body fat. Leptin was significantly correlated with insulin, M_lbm, triglycerides, and blood pressure in heavy children and only with insulin in thin children. After adjustment for body fat, the correlations remained significant for insulin and M_lbm in heavy children and with insulin in thin children. Discussion: Significant associations were found between leptin and insulin resistance in children, and these associations were attenuated by adjustment for adiposity. These findings at age 13 likely have long‐term consequences in the development of the obesity‐insulin resistance‐related cardiovascular risk profile.     

Decrease in Serum Adiponectin Level Due to Obesity and Visceral Fat Accumulation in Children

Objective: To determine whether serum adiponectin is decreased in obesity and is restored toward normal level after treatment in children. Research Methods and Procedures: Subjects were 53 Japanese obese children, 33 boys and 20 girls (6 to 14 years old), and 30 age‐matched nonobese controls for measuring adiponectin (16 boys and 14 girls). Blood was drawn after an overnight fast, and the obese children were subjected to anthropometric measurements including waist and hip circumferences and skinfold thicknesses. Paired samples were obtained from 21 obese children who underwent psychoeducational therapy. Visceral adipose tissue area was measured by computed tomography. Adiponectin was assayed by an enzyme‐linked immunosorbent assay. Results: The serum levels of alanine aminotransferase, uric acid, triglyceride, total cholesterol, low‐density lipoprotein‐cholesterol, total cholesterol/high‐density lipoprotein‐cholesterol, apo B, apo B/apo A₁, and insulin in obese children were higher than the reference values. Serum adiponectin level was lower in the obese children than in the controls (6.4 ± 0.6 vs. 10.2 ± 0.8 mg/L, means ± SEM, p < 0.001). In 21 obese children whose percent overweight declined during therapy, the adiponectin level increased (p = 0.002). The adiponectin level was correlated inversely with visceral adipose tissue area in obese children (r = ?0.531, p < 0.001). The inverse correlations of adiponectin with alanine aminotransferase, uric acid, and insulin were significant after being adjusted for percentage overweight, percentage body fat, or sex. Discussion: Serum adiponectin level is decreased in obese children depending on the accumulation of visceral fat and is restored toward normal level by slimming.     

Obesity,Fasting Plasma Insulin,and C‐Reactive Protein Levels in Healthy Children

Objective: Obesity is associated with hyperinsulinemia and increased level of C‐reactive protein in older children and adults, but little is known about these relationships in very young children. We examined these relationships in healthy 2‐ to 3‐year‐old children. Research Methods and Procedures: Analyses were performed on data from 491 healthy 2‐ to 3‐year‐old Hispanic children enrolled in a dietary study conducted in New York City, 1992 to 1995. Results: Body mass index (BMI), ponderal index, and sum of four skinfolds were highly correlated (r > 0.75) in both boys and girls. Fasting insulin and glucose levels were only modestly correlated (r = 0.37 for boys and r = 0.28 for girls; p < 0.001 for both), but essentially all of the variability in a calculated index of insulin resistance was attributable to variability in fasting insulin level. The correlations of BMI with fasting insulin level were r = 0.16 (p < 0.05) in boys and r = 0.14 (p < 0.05) in girls. In separate multivariate regression analyses adjusting for age and sex, BMI and ponderal index were associated with fasting plasma insulin level (p < 0.001 for both obesity measures). In multivariate regression analyses adjusting simultaneously for age, sex, and either BMI or ponderal index, fasting insulin level, but not these obesity measures, was associated with C‐reactive protein level. Discussion: Obesity is associated with higher fasting insulin level, and fasting insulin is associated with C‐reactive protein level, in healthy 2‐ to 3‐year‐old children.