Amylin and its relation to insulin and lipids in obese children before and after weight loss

Objective: There are limited data concerning the relationships between amylin, weight status, lipids, insulin, and insulin resistance in obese humans. Therefore, the aim was to study these relationships in cross‐sectional and longitudinal analyses. Research Methods and Procedures: Fasting amylin, insulin, glucose, triglycerides, low‐density lipoprotein (LDL)‐ and high‐density lipoprotein (HDL)‐cholesterol, and percentage body fat based on skinfold measurements were determined in 37 obese children (median age, 11.5 years) and compared with 16 lean children of the same age and gender. Furthermore, we analyzed the changes of these variables in the obese children after participating in a one‐year weight loss intervention program. Results: Obese children had significantly (p < 0.01) higher amylin, triglycerides, LDL‐cholesterol, and insulin levels as compared with the lean children. In multiple linear regression analysis, amylin was significantly (p < 0.05) correlated to insulin and triglycerides, but not to age, gender, pubertal stage, or BMI. Changes of amylin correlated significantly (p < 0.001) to changes of insulin (r = 0.54) and triglycerides (r = 0.49), but not to changes of BMI or percentage body fat. Substantial weight loss in 17 children led to a significant (p < 0.05) decrease of amylin, triglycerides, and insulin, in contrast to the 20 children without substantial weight loss. Conclusion: Amylin levels were related to insulin concentrations in both cross‐sectional and longitudinal analyses, suggesting a relationship between amylin and insulin secretion. Amylin levels were reversibly increased in obesity and related to triglyceride concentrations.     

Associations of Aging and Birth Cohort with Body Mass Index in a Biethnic Cohort

Objective: To examine associations of aging and birth cohort with body mass index (BMI) in a biethnic cohort. Research Methods and Procedures: This was a longitudinal closed cohort study of 14, 500 white and African‐American men and women, 45 to 64 years of age, followed for 9 years. Aging was defined as the length of the interval in years between baseline and following visits. Birth cohort was defined by the year in which participants were born. Mixed model analyses were used to examine associations of aging, birth cohort, and BMI in four ethnicity‐gender groups. Results: We found that aging was associated with an increase in BMI in white and African‐American men and women. The associations between aging and BMI were stronger in the younger birth cohorts. Except for white women, younger birth cohort was associated with a higher BMI. After adjusting for aging, birth cohort was associated with an increase in BMI of 0.1 kg/m² [95% confidence interval (95% CI): ?0.1, 0.3] among white women. The corresponding values for African‐American women, white men, and African‐American men are 0.5 kg/m² (95% CI: 0.1, 0.9), 0.6 kg/m² (95% CI: 0.4, 0.8), and 0.6 kg/m² (95% CI: 0.2, 1.0), respectively. Discussion: Our analyses show that, in all except white women, people in this age range who were born later have a higher BMI at the same attained age. In all groups, people who are born later gained more weight as they aged. In general, subjects ages 45 to 64 years gained weight as they aged 9 years.     

Family Dinner and Adolescent Overweight

Objective: The purpose of this study was to examine both cross‐sectional and longitudinal associations between frequency of family dinner and overweight status in a large sample of 9‐ to 14‐year‐old children. Research Methods and Procedures: We studied a cohort of 7784 girls and 6647 boys, 9 to 14 years of age at baseline in 1996, participating in the Growing Up Today Study. From annual mailed surveys, we calculated BMI from self‐reported height and weight and assessed frequency of family dinner over the previous year. We defined “overweight” as age‐ and sex‐specific BMI >85th percentile. We performed multiple logistic regression analyses; the longitudinal analyses assessed the association of previous year family dinner consumption with 1‐year incidence of becoming overweight, using prospective data from 1996 through 1999. Results: At baseline in 1996, 16% of participants had family dinner “never or some days,” 40% on “most days,” and 44% “every day.” Across these categories, overweight prevalence for girls was 19.4%, 16.6%, and 16.7% and for boys was 24.6%, 23.3%, and 22.7%, respectively. In cross‐sectional analyses, adjusting for potential confounders, the odds of being overweight was 0.85 [95% confidence interval (CI): 0.76, 0.96] among children who ate family dinner on “most days” or “every day” compared with those who ate family dinner “never or some days.” In longitudinal multivariate models, the odds ratios between previous year frequency of eating family dinner and 1‐year incidence of becoming overweight were 0.95 (95% CI: 0.78, 1.16) and 1.04 (95% CI: 0.85, 1.27) for children who ate family dinner on “most days” and “every day,” respectively, compared with those who ate family dinner “never or some days.” Discussion: The frequency of eating family dinner was inversely associated with overweight prevalence at baseline but not with likelihood of becoming overweight in longitudinal analyses.     

Racial differences in correlates of misreporting of energy intake in adolescent females

Objective: To determine the extent of misreporting of energy intake (EI) and its anthropometric, demographic, and psychosocial correlates in a bi‐racial cohort of young women. Research Methods and Procedures: This was a cross‐sectional study of 60 black and 60 white young women, 18 to 21 years old, enrolled in a longitudinal study. Total energy expenditure was assessed using doubly labeled water. Self‐reported EI was obtained from 3‐day food records. BMI was computed from height and weight. Fat mass was assessed by DXA. Multivariate analyses examined racial differences on the extent of misreporting and its effect on other potential correlates of misreporting. Race‐specific step‐wise linear regression analysis was performed to examine the effect of BMI, parental education, and drive for thinness on misreporting of EI. Results: More white women tended to under‐report EI than black women (22% vs. 13%, p = 0.07). In black women, under‐reporting was significantly (p = 0.01) associated with drive for thinness score but was only marginally (p = 0.1) associated with BMI. Each point increase in drive for thinness score was associated with under‐reporting by 40 kcal/d. In white women, under‐reporting was significantly (p = 0.03) associated with higher parental education by 440 kcal/d and also only marginally (p = 0.09) with BMI. Discussion: This tendency for under‐reporting of EI limits the use of self‐reported EI in studying energy balance in free‐living subjects. Most black and almost all white women in their late teens significantly under‐reported their EI, whereas under‐reporting was not as evident among lean young black women.     

Lifecourse socioeconomic position and weight change among blacks: The Pitt County study

Objective: The elevated prevalence of obesity among U.S. blacks has been attributed to low socioeconomic position (SEP), despite inconsistent empirical findings. It is unclear whether low SEP at various lifecourse stages differentially influences adulthood BMI and BMI change. Research Methods and Procedures: Among 1167 black adults in the Pitt County Study, we examined independent cross‐sectional and longitudinal associations between SEP, measured in childhood and adulthood, and BMI and 13‐year BMI change. Low vs. high childhood SEP was measured by parental occupation and childhood household deprivation; low vs. high adulthood SEP was assessed by employment status, education, and occupation. Using childhood and adulthood SEP, four lifecourse SEP categories were created: low‐low, low‐high, high‐low, high‐high. Results: We found no consistent associations between SEP and BMI or BMI change among men. Among women, we observed the expected inverse association between SEP and BMI at baseline. In multivariable‐adjusted analyses, socioeconomically advantaged women demonstrated larger 13‐year increases in BMI: skilled vs. unskilled parental occupation (6.1 vs. 4.8 kg/m², p = 0.04); college‐educated vs. < high school (6.2 vs. 4.5 kg/m², p = 0.04); white‐collar vs. blue‐collar job (5.8 vs. 4.8 kg/m², p = 0.05); and high‐high vs. low‐low lifecourse SEP (6.5 vs. 4.6 kg/m², p = 0.02). Discussion: For women in this black cohort, lower SEP predicted earlier onset of obesity; however, low SEP was less predictive of BMI increases over time. Our findings demonstrate complex patterns of association between SEP and BMI change among black women.     

Weight cycling and 6-year weight change in healthy adults: The Aerobics Center Longitudinal Study

Objective: To determine the longitudinal relationship between a reported history of weight cycling and the trajectory of weight in a group of normal‐weight to obese women and men. Research Methods and Procedures: This was a clinic‐based cohort study conducted over 6 years. Subjects were healthy women (n = 141) and men (n = 797) age 20 to 78 years who completed at least four comprehensive medical exams at the Cooper Clinic (Dallas, TX) between 1987 and 2003. Weight loss history was reported, and body weight was measured at all examinations. Weight cycling status was derived from weight loss history and defined as ≥five episodes of weight loss of ≥2.3 kg/episode. Using linear mixed effects models, weight at each examination was regressed on weight cycling status separately for women and men while controlling for selected covariables. Results: Baseline BMI was 23 and 21 kg/m² among cycling and non‐cycling women and was 27 and 25 kg/m² among cycling and non‐cycling men, respectively. We observed a non‐significant difference (p = 0.09) in women by cycling status (average weight gain = 0.5 and 0.2 kg/yr among cyclers and non‐cyclers, respectively) and no difference in weight gain over time among men by cycling status (average weight gain = 0.2 kg/yr among both groups, p = 0.99). Higher baseline cardiorespiratory fitness level and increased fitness over the follow‐up were associated with attenuated weight gain in both women and men. Discussion: In healthy, middle‐aged individuals, a history of weight cycling does not seem to increase the risk of long‐term weight gain in men; however, this relation needs to be studied further in women.     

Cross‐Sectional and Longitudinal Associations of BMI with Socioeconomic Characteristics

Objective: To examine cross sectional and longitudinal associations of socioeconomic position and neighborhood environments with BMI in a middle‐aged and bi‐ethnic cohort. Research Methods and Procedures: Analyses were based on 13, 167 subjects (45 to 64 years) who participated in the Atherosclerosis Risk in Communities Study, a population‐based study. Census block groups were used as proxies for neighborhoods and were characterized using a summary socioeconomic score. BMI was measured at baseline and at three follow‐up visits over a 9‐year period. Results: Individual and neighborhood socioeconomic characteristics were independently and inversely associated with BMI at baseline in women [mean difference in kilograms per meter squared per unit increase in socioeconomic category (SE) for white and black women respectively; ?1.56 (0.14), ?1.59 (0.19) for education; ?1.07 (0.10), ?1.18 (0.18) for income; and ?1.04 (0.09), ?0.77 (0.18) for neighborhood characteristics]. Results for men were not as consistent. Baseline BMI was negatively associated with income in white men but was positively associated with education, income, and neighborhood characteristics in black men. BMI increased over time regardless of gender or race and in most age groups. In whites, there were no consistently patterned differences in longitudinal trends in BMI by individual or neighborhood socioeconomic characteristics. However, in blacks, there was some evidence of greater increases in the higher socioeconomic status groups. Discussion: Socioeconomic factors are inversely associated with BMI in middle‐aged women, possibly reflecting socially patterned exposures occurring in childhood and adolescence. However, recent increases over time in BMI are either not clearly patterned by socioeconomic factors or are greater in the higher socioeconomic status groups.     

Ethnic and sex variations in overweight self-perception: relationship to sedentariness

Objective: With increasing frequency, health promotion messages advocating physical activity are claiming weight loss as a benefit. However, messages promoting physical activity as a weight loss strategy may have limited effectiveness and cross‐cultural relevance. We recently found self‐perceived overweight to be a more robust correlate of sedentary behavior than BMI in Los Angeles County adults. In this study, we examined ethnic and sex differences in overweight self‐perception and their association with sedentariness in this sample. Research Methods and Procedures: We conducted bivariate and multivariate analyses of cross‐sectional survey data from a representative sample of Los Angeles County adults. Results: Women were more likely to perceive themselves to be overweight than men overall (73.2% of overweight/non‐obese and 24.1% of average weight women vs. 44.5% of overweight/non‐obese and 5.6% of average weight men) and within each ethnic group. African‐Americans were least likely (41.3% of overweight/non‐obese African‐Americans self‐identified as overweight) and whites were most likely to consider themselves overweight (60.6% of overweight/non‐obese whites self‐identified as overweight). Overweight (vs. average weight) self‐perception was correlated with sedentariness among average weight adults (45.3% vs. 33.0%, p < 0.001), overweight adults (43.4% vs. 33.6%, p < 0.001), men (average and overweight: 38.4% vs. 27.8%, p < 0.001), overweight whites (41.9% vs. 29.7%, p = 0.0012), and African‐Americans and Latinos (41.6% vs. 33.9%, p = 0.005). Discussion: These data suggest that our society's emphasis on weight loss rather than lifestyle change may inadvertently discourage physical activity adoption/maintenance among non‐obese individuals. However, further research is needed, particularly from prospective cohort and intervention studies, to elucidate the relationship between overweight self‐perception and healthy lifestyle change.     

Interactive Effects Between Polymorphisms in the β‐Adrenergic Receptors and Longitudinal Changes in Obesity

We assessed interactions between polymorphisms in the β‐adrenergic receptor genes and longitudinal changes in obesity from childhood to adulthood using longitudinal data collected over a 24‐year period from 1973 to 1996. Sex‐ and age‐stratified analyses using random coefficients models were used to examine gene—gene interaction effects on obesity measures in 1179 African‐American and white men and women (71% white, 57% women). Suggestive evidence for an interaction (p = 0.022) between the β1‐ and β2‐adrenergic receptors was observed in men for longitudinal change in BMI. Men with Gly/Gly genotypes for both the β1 and β2 receptors showed significant increases (～0.6%/yr) in BMI from childhood to adulthood. Women showed suggestive evidence for an interaction (p = 0.035) between the β1‐ and β3‐adrenergic receptors for change over time in BMI. Women with Gly/Gly genotypes at the β1‐receptor and carrying at least one β3‐Arg allele showed notable increases in BMI. The regulation of lipolysis and development of obesity differ markedly between men and women and may be influenced by genetic polymorphisms, which contribute to the efficiency of the β‐adrenergic receptors, and hormonal effects on adrenergic receptor activity.     

Larger Thigh and Hip Circumferences Are Associated with Better Glucose Tolerance: The Hoorn Study

Objective: A higher waist‐to‐hip ratio, which can be due to a higher waist circumference, a lower hip circumference, or both, is associated with higher glucose levels and incident diabetes. A lower hip circumference could reflect either lower fat mass or lower muscle mass. Muscle mass might be better reflected by thigh circumference. The aim of this study was to investigate the contributions of thigh and hip circumferences, independent of waist circumference, to measures of glucose metabolism. Research Methods and Procedures: For this cross‐sectional study we used baseline data from the Hoorn Study, a population‐based cohort study of glucose tolerance among 2484 men and women aged 50 to 75. Glucose tolerance was assessed by a 75‐g oral glucose tolerance test; hemoglobin A_1c and fasting insulin were also measured. Anthropometric measurements included body mass index (BMI) and waist, hip, and thigh circumferences. Results: Stratified analyses and multiple linear regression showed that after adjustment for age, BMI, and waist circumference, thigh circumference was negatively associated with markers of glucose metabolism in women, but not in men. Standardized β values in women were ?0.164 for fasting, ?0.206 for post‐load glucose, ?0.190 for hemoglobin A_1c (all p < 0.001), and ?0.065 for natural log insulin levels (p = 0.061). Hip circumference was negatively associated with markers of glucose metabolism in both sexes (standardized betas ranging from ?0.093 to ?0.296, p < 0.05) except for insulin in men. Waist circumference was positively associated with glucose metabolism. Discussion: Thigh circumference in women and hip circumference in both sexes are negatively associated with markers of glucose metabolism independently of the waist circumference, BMI, and age. Both fat and muscle tissues may contribute to these associations.     

The Association between Plasma Adiponectin and Insulin Sensitivity in Humans Depends on Obesity

Objective: In humans, low plasma adiponectin concentrations precede a decrease in insulin sensitivity and predict type 2 diabetes independently of obesity. However, it is possible that the contribution of adiponectin to insulin sensitivity is not equally strong over the whole range of obesity. Research Methods and Procedures: We investigated the cross‐sectional association between plasma adiponectin levels and insulin sensitivity in different ranges of body fat content [expressed as percentage of body fat (PFAT)] in a large cohort of normal glucose‐tolerant subjects (n = 900). All individuals underwent an oral glucose tolerance test (OGTT), and 299 subjects additionally a euglycemic hyperinsulinemic clamp. In longitudinal analyses, the association of adiponectin at baseline with change in insulin sensitivity was investigated in a subgroup of 108 subjects. Results: In cross‐sectional analyses, the association between plasma adiponectin and insulin sensitivity, adjusted for age, gender, and PFAT, depended on whether subjects were lean or obese [p for interaction adiponectin × PFAT = <0.001 (OGTT) and 0.002 (clamp)]. Stratified by quartiles of PFAT, adiponectin did not correlate significantly with insulin sensitivity in subjects in the lowest PFAT quartile (R² = 0.10, p = 0.13, OGTT; and R² = 0.10, p = 0.57, clamp), whereas the association in the upper PFAT quartile was rather strong (R² = 0.36, p < 0.0001, OGTT; and R² = 0.48, p = 0.003, clamp). In longitudinal analyses, plasma adiponectin at baseline preceded change in insulin sensitivity in obese (n = 54, p = 0.03) but not in lean (n = 54, p = 0.68) individuals. Discussion: These data suggest that adiponectin is especially critical in sustaining insulin sensitivity in obese subjects. Thus, interventions to reduce insulin resistance by increasing adiponectin concentrations may be effective particularly in obese, insulin‐resistant individuals.     

Forecasting the obesity epidemic in the aging U.S. population

Objective: The objective was to forecast BMI distribution in the U.S. population along with demographic changes based on past race‐, sex‐, and birth cohort‐specific secular trends. Research Methods and Procedures: We compiled data from 44,184 subjects from 4 National Health and Nutrition Examination Surveys (NHANES; 1971 to 2004). By race and sex, we fit regression models to create smoothed mean BMI curves by age for 1970 to 2010. Linking corresponding birth cohorts across age‐ and year‐specific mean BMI projections, we estimated the trajectory of relative BMI throughout each cohort's lifetime. These projections were validated using actual cohorts in the Nurses’ Health Study and Health Professionals Follow‐up Study. Combined with U.S. census, we predicted BMI distributions in 2010 and examined the joint impact of the obesity epidemic and population aging. Results: BMI secular trends in the past 3 decades differ significantly by birth cohort, sex, and race. If these trends continue, the prevalence of obesity is expected to reach 35%, 36%, 33%, and 55% in 2010 among white men, white women, black men, and black women, respectively, far from the Healthy People 2010 goal of 15%. Such forecasts translate into 9.3 million more obese adults 20 to 74 years of age than in 2000, 8.3 million of whom would be 50 years of age or older, and 8.5 million of whom would be white. The mean age among obese men and women is also expected to rise from 47 to 49 years among whites and from 43 to 44 years among blacks. Discussion: As the baby boom generation approaches retirement age, the continuing obesity epidemic signals a likely expansion in the population with obesity‐related comorbidities. A framework to combine BMI and demographic trends is essential in evaluating the burden and disparity associated with the epidemic in the aging U.S. population.     

Prospective associations between sedentary lifestyle and BMI in midlife

Objective: A strong positive cross‐sectional relationship between BMI and a sedentary lifestyle has been consistently observed in numerous studies. However, it has been questioned whether high BMI is a determinant or a consequence of a sedentary lifestyle. Research Methods and Procedures: Using data from four follow‐ups of the University of North Carolina Alumni Heart Study, we examined the prospective associations between BMI and sedentary lifestyle in a cohort of 4595 middle‐aged men and women who had responded to questionnaires at the ages of 41 (standard deviation 2.3), 44 (2.3), 46 (2.0), and 54 (2.0). Results: BMI was consistently related to increased risk of becoming sedentary in both men and women. The odds ratios of becoming sedentary as predicted by BMI were 1.04 (95% confidence limits, 1.00, 1.07) per 1 kg/m² from ages 41 to 44, 1.10 (1.07, 1.14) from ages 44 to 46, and 1.12 (1.08, 1.17) from ages 46 to 54. Controlling for concurrent changes in BMI marginally attenuated the effects. Sedentary lifestyle did not predict changes in BMI, except when concurrent changes in physical activity were taken into account (p < 0.001). The findings were not confounded by preceding changes in BMI or physical activity, age, smoking habits, or sex. Discussion: Our findings suggest that a high BMI is a determinant of a sedentary lifestyle but did not provide unambiguous evidence for an effect of sedentary lifestyle on weight gain.     

Hypertriglyceridemic waist phenotype is associated with decreased insulin sensitivity and incident diabetes in elderly men

Objective: To investigate the association between hypertriglyceridemic waist (HTGW) and insulin sensitivity (assessed by euglycemic clamp method), and the development of diabetes in a longitudinal community‐based cohort of elderly men without diabetes at baseline. Design and Methods: The present cross‐sectional study comprised 1,026, 70‐year‐old men without diabetes. The gold standard euglycaemic–hyperinsulinaemic clamp technique was used. Six‐year follow‐up on diabetes status were available in n = 667. The HTGW phenotype was defined as having waist circumference ≥ 90 cm, and triglycerides ≥ 2 mmol L^?1. The men were stratified into those having normal WC and TG (n = 299), one HTGW component (n = 606), and HTGW (n = 121). Results: The association between insulin sensitivity and one HTGW component as well as HTGW was highly significant (P < 0.001) in the whole sample, as well as in individuals with high/low BMI (stratified at ≥25). In longitudinal analyses, participants with HTGW was associated with a more than fourfold increased risk for diabetes (Odds ratio 4.64, 95% CI 1.61–13.4, P = 0.004) compared to those with normal WC and TG. Conclusion: The present study both confirm and extend previous research suggesting that the HTGW‐phenotype portrays an increased glucometabolic risk, also in lean individuals.     

Long-term effects of obesity on employment and work limitations among U.S. Adults, 1986 to 1999

Objective: To determine the relationships between BMI and workforce participation and the presence of work limitations in a U.S. working‐age population. Research Methods and Procedures: We used data from the Panel Study of Income Dynamics, a nationwide prospective cohort, to estimate the effect of obesity in 1986 on employment and work limitations in 1999. Individuals were classified into the following weight categories: underweight (BMI < 18.5), normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30). Using multivariable probit models, we estimated the relationships between obesity and both employment and work disability. All analyses were stratified by sex. Results: After adjusting for baseline sociodemographic characteristics, smoking status, exercise, and self‐reported health, obesity was associated with reduced employment at follow‐up [men: marginal effect (ME) ?4.8 percentage points (pp); p < 0.05; women: ME ?5.8 pp; p < 0.10]. Among employed women, being either overweight or obese was associated with an increase in self‐reported work limitations when compared with normal‐weight individuals (overweight: ME +3.9 pp; p < 0.01; obese: ME +12.6 pp; p < 0.01). Among men, the relationship between obesity and work limitations was not statistically significant. Discussion: Obesity appears to result in future productivity losses through reduced workforce participation and increased work limitations. These findings have important implications in the U.S., which is currently experiencing a rise in the prevalence of obesity.     

Risk Factors for Adult Overweight and Obesity in the Quebec Family Study: Have We Been Barking Up the Wrong Tree?

The aim of this study was to determine the independent contribution of previously reported risk factors for adult overweight and obesity. A cross‐sectional (n = 537) and a longitudinal (n = 283; 6‐year follow‐up period) analysis was performed for nine risk factors for overweight and obesity assessed in adult participants (aged 18–64 years) of the Quebec Family Study (QFS). The main outcome measure was overweight/obesity, defined as a BMI ≥25 kg/m². Using logistic regression analysis adjusted for age, sex, and socioeconomic status, short sleep duration, high disinhibition eating behavior, low dietary calcium intake, high susceptibility to hunger behavior, nonparticipation in high‐intensity physical exercise, high dietary restraint behavior, nonconsumption of multivitamin and dietary supplements, high dietary lipid intake, and high alcohol intake were all significantly associated with overweight and obesity in the cross‐sectional sample. The analysis of covariance adjusted for age, socioeconomic status, and all other risk factors revealed that only individuals characterized by short sleep duration, high disinhibition eating behavior, and low dietary calcium intake had significantly higher BMI compared to the reference category in both sexes. Over the 6‐year follow‐up period, short‐duration sleepers, low calcium consumers, and those with a high disinhibition and restraint eating behavior score were significantly more likely to gain weight and develop obesity. These results show that excess body weight or weight gain results from a number of obesogenic behaviors that have received considerable attention over the past decade. They also indicate that the four factors, which have the best predictive potential of variations in BMI, be it in a cross‐sectional or a longitudinal analytical design, do not have a “caloric value” per se.     

Which Obesity Index Best Explains Prevalence Differences in Type 2 Diabetes Mellitus?

Objective: Obesity drives the diabetes epidemic. However, it is not known which obesity index best explains variations in type 2 diabetes mellitus prevalence across populations. Research Methods and Procedures: We analyzed three cross‐sectional studies from San Antonio, TX, (Mexican‐Americans and non‐Hispanic whites, n = 2839), Mexico City (n = 2233), and Spain (n = 2161) (age range, 35 to 64 years). We used the area under the receiver operating characteristic curve (AUC) to assess performance for identifying diabetic subjects and logistic regression analysis to examine differences in diabetes prevalence. Results: AUCs for waist circumference and BMI were similar in white subjects, but the AUC for waist circumference was greater in Mexican‐origin subjects (Mexican men, 0.594 vs. 0.549, p = 0.008; and women, 0.605 vs. 0.557, p = 0.002; Mexican‐American men, 0.648 vs. 0.600, p < 0.001; and women, 0.744 vs. 0.693, p < 0.001). The AUC for waist‐to‐height ratio tended to be greater than that for waist circumference, but statistical significance was demonstrated only in Mexican women (0.628 vs. 0.613, p = 0.044), Mexican‐American women (0.774 vs. 0.758, p < 0.001), and Spanish women (0.734 vs. 0.715, p = 0.039). No obesity index was consistently superior to the others for explaining differences in diabetes prevalence among populations. Conclusions: In white and Mexican‐origin men, waist circumference may be the preferred marker for identifying diabetic subjects on account of its simplicity; in women, waist‐to‐height ratio may be better. Differences in diabetes prevalence among these populations cannot be attributed to a single measure of obesity.     

Predictors of Long‐term Weight Maintenance

Objective: The purpose of this study was to evaluate available variables of a long‐term weight maintenance study to investigate possible factors predisposing to weight regain after a period of weight loss. Research Methods and Procedures: The Maastricht Weight Maintenance Study is an ongoing longitudinal study of healthy men and women (29 men and 62 women; 18 to 65 years of age; BMI = 30.2 ± 3.1 kg/m²). A variety of parameters were measured before and after a very‐low‐energy diet and after a follow‐up of at least 2 years. Results: Mean weight loss was 7.9 ± 3.6 kg, and percent weight regain was 113.8 ± 98.1%. Percent BMI regain was negatively associated with an increase in dietary restraint (r = ?0.47, p < 0.05). Percent weight regain was negatively correlated with baseline resting metabolic rate (r = ?0.38, p = 0.01) and baseline fat mass (r = ?0.24, p = 0.05) and positively correlated with the magnitude of change in body weight (BW) expressed as maximum amplitude of BW (r = 0.21, p < 0.05). In addition, amplitude of BW was positively correlated with the frequency of dieting (r = 0.57, p < 0.01). Discussion: The best predictors for weight maintenance after weight loss were an increase in dietary restraint during weight loss, a high baseline resting metabolic rate, a relatively high baseline fat mass favoring a fat‐free mass–sparing effect during weight loss, a rather stable BW, and a low frequency of dieting. Therefore, BW maintenance after BW loss seems to be a multifactorial issue, including mechanisms that regulate an individuals’ energy expenditure, body composition, and eating behavior in such a way that energy homeostasis is maintained.     

Overweight and Obesity in Young and Middle Age and Early Retirement: The ARIC Study

The objective of this study was to examine associations between weight status in young and middle age and early retirement in African‐American and white men and women. Data were from the Atherosclerosis Risk in Communities (ARIC) study. Analyses were restricted to participants aged 45–55 years at baseline (n = 6,483). Associations between weight status at age 25 and ages 45–55 and age at early retirement (prior to age 65) over 9 years of follow‐up were examined using proportional hazard regression analyses in models stratified by race and gender. Models were adjusted for education, household income, health insurance status, occupation, occupational physical activity, marital status, smoking, and field center. Between 18.7 and 21.6% of African‐American and white men and women reported retiring prior to age 65. Although not always statistically significant, overweight and obesity were associated with early retirement in all but white women. Overweight (BMI ≥ 25 kg/m²) at age 25 was significantly associated with early retirement in African‐American women (hazard ratio (95% confidence interval): 1.62 (1.17–2.23)) and white men (1.32 (1.12–1.57)). There was also a trend between overweight at age 25 and early retirement in African‐American men (1.43 (0.99–2.07)). Obesity (BMI ≥ 30 kg/m²) in middle age was significantly associated with early retirement in white men only (1.32 (1.03–1.69)). Furthermore, overweight at age 25 and obesity at ages 45–55 were associated with early retirement for health reasons among African‐American and white men and women. In conclusion, analyses of the economic impact of obesity may need to consider its effects on early retirement.     

Birth Weight,Adult Body Composition,and Subcutaneous Fat Distribution

Objectives: To investigate if birth weight is related to both body mass index (BMI) and distribution of subcutaneous fat at adult age. Research Methods and Procedures: A 9‐year longitudinal study was performed in 229 subjects (192 women) with ages ranging from 27 to 36 years. Birth weight was retrieved by a questionnaire, and adult weight, height, skinfold thicknesses, and waist‐to‐hip ratio (WHR) were repeatedly measured at mean ages 27, 29, 31, and 36 years. BMI, sum of four skinfolds (S4S), the ratio between two truncal skinfolds and S4S (SS/S4S), and the ratio between WHR and the cross‐sectional area of the left thigh were calculated with the available data. Results: The adjusted model showed that in women, birth weight was significantly negatively related to adult S4S [β = ?5.211; (?9.768 to ?0.654)], waist circumference [β = ?1.449; (?2.829 to ?0.069)], and SS/S4S ratio [β = ?3.579; (?5.296 to ?1.862)]. In men, a significant negative association was observed between birth weight and adult WHR [β = ?1.096; (?2.092 to ?0.100)] only. Other relationships showed, although not significantly, the same negative trend, namely that lower birth weight is related to higher adult body fat mass (S4S) and a more truncal subcutaneous fat distribution (SS/S4S). No associations were found between birth weight and either adult BMI or the cross‐sectional area of the thigh. Discussion: Lower birth weight is, in both adult men and women, related to a higher adult subcutaneous fat mass and a more truncal distribution of subcutaneous fat, indicating a higher risk for obesity.