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.     

Birthplace, years of residence in the United States, and obesity among Mexican-American adults

Objective: To evaluate the association between birthplace (Mexico or U.S.) and obesity in men and women and to analyze the relationship between duration of U.S. residency and prevalence of obesity in Mexican immigrants. Research Methods and Procedures: We used cross‐sectional data from 7503 adults of Mexican descent residing in Harris County, TX, to evaluate the relationships among BMI, birthplace, and years of residency in the U.S., controlling for demographic characteristics, physical activity level, and acculturation level. Results: U.S.‐born adults had an increased risk (between 34% and 65%) of obesity compared with their Mexican‐born counterparts. After controlling for recognized confounders and risk factors, this association was maintained in the highly acculturated only. Among highly acculturated obese U.S.‐born men, 6% of the cases were attributable to the joint effect of birthplace and acculturation; in women, this proportion was 25%. Among Mexican‐born women, there was an increasing trend in mean BMI with increasing duration of residency in the U.S. Compared with immigrants who had lived in the U.S. for <5 years, Mexican‐born women who had resided in the U.S. for ≥15 years had an adjusted BMI mean difference of 2.12 kg/m² (95% confidence interval, 1.53–2.72). Discussion: Mexican‐born men and women have a lower risk of obesity than their U.S.‐born counterparts, but length of U.S. residency among immigrants, especially in women, is directly associated with risk of obesity. Development of culturally specific interventions to prevent obesity in recent immigrants may have an important public health effect in this population.     

Work‐Related Physical Activity Is Not Associated with Body Mass Index and Obesity

Objective: To analyze the association of work‐related physical activity (WRPA) and leisure‐time physical activity (LTPA) with body mass index (BMI) and obesity in the Spanish adult population aged 20 to 60 years. Research Methods and Procedures: The data were taken from the 1993 Spanish National Health Survey. We analyzed a sample of 12,044 men and women representative of the Spanish population aged 20 to 60 years. BMI and frequency of obesity (BMI ≥ 30 kg/m²) were obtained from self‐reported weight and height. Multiple linear regression and logistic regression models were constructed, adjusting for the main confounding factors. WRPA and LTPA were measured by two questions to classify subjects into four categories of physical activity. Results: Neither mean BMI nor percentage of obesity varied significantly (p > 0.05) by WRPA. Mean BMI was significantly higher (p < 0.01) in those who were inactive in their leisure time (25.90 kg/m² in men and 24.43 kg/m² in women) than in those who reported vigorous activity (24.42 kg/m² and 22.97 kg/m² in men and women, respectively). The odds ration (OR) for obesity decreased with increasing level of LTPA in both men (OR of 0.64 for vigorous activity) and women (OR = 0.68), showing a statistically significant dose‐response relation in both men (for linear trend, p = 0.0021) and women (p = 0.0245). Discussion: These results raise questions about the association between WRPA and obesity and suggest the need to reexamine models of the obesity epidemic that point to automation of the workplace as one of the major explanatory factors.     

Overall and central obesity and risk of type 2 diabetes in U.S. black women

Objective: Obesity has risen to epidemic proportions in the United States, leading to an emerging epidemic of type 2 diabetes. African‐American women are disproportionately affected by both conditions. While an association of overall obesity with increasing risk of diabetes has been documented in black women, the effect of fat distribution, specifically abdominal obesity, has not been studied. We examined the association of BMI, abdominal obesity, and weight gain with risk of type 2 diabetes. Research Methods and Procedures: During eight years of follow‐up of 49,766 women from the Black Women's Health Study, 2472 incident cases of diabetes occurred. Cox proportional hazard models were used to estimate incidence rate ratios (IRRs), with control for age, physical activity, family history of diabetes, cigarette smoking, years of education, and time period of data collection. Results: Sixty‐one percent of participants had a BMI ≥25 kg/m² (WHO definition of overweight). Compared with a BMI of <23 kg/m², the IRR for a BMI of >45 kg/m² was 23 (95% confidence interval, 17.0 to 31.0). The IRR for the highest quintile of waist‐to‐hip ratio relative to the lowest was 2.3 (95% confidence interval, 2.0 to 2.7) after control for BMI. Furthermore, at every level of BMI, an increased risk was observed for high waist‐to‐hip ratio relative to low. Discussion: Central obesity, as well as overall obesity, is a strong risk factor for diabetes in African‐American women. Efforts to reduce the prevalence of obesity in African‐American women are of paramount importance.     

Obesity indices and self-reported functional health in men and women in the EPIC-Norfolk

Objective: To investigate the association between two indices of obesity, BMI and waist‐to‐hip ratio (WHR), and self‐reported physical and mental functional health. Research Methods and Procedures: We examined the relationship between obesity indices and self‐reported physical and mental functional health measured by the Anglicized version of the Short‐Form 36‐item questionnaire in a population‐based cross sectional study of 16, 806 men and women 40 to 79 years old living in the general community in Norfolk, United Kingdom. Results: Higher BMI and WHR were both independently associated with poorer self‐reported physical functional health in men and women. The effect of BMI was greater in women compared with men, and the effect of WHR was greater in men compared with women, for poor physical functional health. Higher WHR but not BMI was associated with lower mental functional health in men and women. Discussion: High BMI and WHR seem to be adversely related to self‐perceived functional health in both men and women, although their relative impacts seem to differ by sex. Our findings also highlight the importance of using WHR in addition to BMI in assessing the impact of obesity on health outcome.     

Secular trends of obesity and cardiovascular risk factors in a Mediterranean population

Objective: To evaluate time trends of obesity, abdominal obesity, and cardiovascular risk factors (CRFs) according to BMI and waist circumference (WC) categories in a Mediterranean population. Research Methods and Procedures: Subjects were Spanish men (n = 2383) and women (n = 2525) 25 to 74 years old, examined in 1994 to 1995 and 1999 to 2000 in two independent population‐based cross‐sectional surveys in the northeast of Spain. Lifestyle measures, CRFs, and anthropometric variables were analyzed. Results: Over the 5 years of the study, mean age‐standardized BMI increased by 1.0 units in men and by 0.8 units in women. At the same time the prevalence of obesity increased from 15.4% to 21.9% in men and from 15.4% to 21.4% in women. An upward trend was observed for WC and abdominal obesity (WC > 102 cm in men and WC > 88 cm in women) only in men. The proportion of men and women with hypercholesterolemia, diabetes, and low high‐density lipoprotein‐cholesterol plasma concentration remained stable within BMI and WC categories. The proportion of hypertension and smoking in obese men significantly increased from 1995 to 2000. Discussion: The 5‐year increase in BMI and WC is of considerable magnitude in the present population, although several CRFs remained stable within BMI and WC categories.     

Moderate and Severe Obesity Have Large Differences in Health Care Costs

Objective: To analyze health care use and expenditures associated with varying degrees of obesity for a nationally representative sample of individuals 54 to 69 years old. Research Methods and Procedures: Data from the Health and Retirement Study, a nationwide biennial longitudinal survey of Americans in their 50s, were used to estimate multivariate regression models of the effect of weight class on health care use and costs. The main outcomes were total health care expenditures, the number of outpatient visits, the probability of any inpatient stay, and the number of inpatient days. Results: The results indicated that there were large differences in obesity‐related health care costs by degree of obesity. Overall, a BMI of 35 to 40 was associated with twice the increase in health care expenditures above normal weight (about a 50% increase) than a BMI of 30 to 35 (about a 25% increase); a BMI of over 40 doubled health care costs (～100% higher costs above those of normal weight). There was a difference by gender in how health care use and costs changed with obesity class. The primary effect of increasing weight class on health care use appeared to be through elevated use of outpatient health care services. Discussion: Obesity imposes an increasing burden on the health care system, and that burden grows disproportionately large for the most obese segment of the U.S. population. Because the prevalence of severe obesity is increasing much faster than that of moderate obesity, average estimates of obesity effects obscure real consequences for individuals, physician practices, hospitals, and health plans.     

Nut consumption and weight gain in a Mediterranean cohort: The SUN study

Objective: To assess the association, in a Mediterranean population, between nut consumption and risk of weight gain (at least 5 kg) or the risk of becoming overweight/obese. Research Methods and Procedures: The Seguimiento Universidad de Navarra project is a prospective cohort of 8865 adult men and women who completed a follow‐up questionnaire after a median of 28 months. Dietary habits were assessed with a previously validated semiquantitative food‐frequency questionnaire. Results: Nine hundred thirty‐seven participants reported a weight gain of ≥5 kg at follow‐up. After adjusting for age, sex, smoking, leisure time physical activity, and other known risk factors for obesity, participants who ate nuts two or more times per week had a significantly lower risk of weight gain (odds ratio: 0.69; 95% confidence interval: 0.53 to 0.90, p for trend = 0.006) than those who never or almost never ate nuts. Participants with little nut consumption (never/almost never) gained an average of 424 grams (95% confidence interval: 102 to 746) more than frequent nut eaters. Nut consumption was not significantly associated with incident overweight/obesity in the cohort. Discussion: Frequent nut consumption was associated with a reduced risk of weight gain (5 kg or more). These results support the recommendation of nut consumption as an important component of a cardioprotective diet and also allay fears of possible weight gain.     

Prevalence of Pre‐obesity and Obesity in Urban Adult Mexicans in Comparison with Other Large Surveys

Objective: 1. To estimate the prevalence of pre‐obesity and obesity in a 1992 to 1993 national survey of the Mexican urban adult population. 2. To compare our findings with other national surveys and with data for Mexican Americans. Research Methods and Procedures: The national representative sample of the Mexican urban adult population included 8462 women and 5929 men aged 20 to 69 years from 417 towns of >2500 people. Body mass index (BMI), calculated from measured weight and height, was classified using the World Health Organization categories of underweight (BMI < 18.5 kg/m²), normal weight (BMI 18.5 to 24.9 kg/m²), pre‐obesity (PreOB = BMI 25 to 29.9 kg/m²) and obesity (OB = BMI 30+ kg/m²). Estimates for Mexican Americans were calculated from U.S. survey data. Results: Overall, 38% of the Mexican urban adult population were classified as pre‐obese and 21% as obese. Men had a higher prevalence of pre‐obesity than women did at all ages, but women had higher values of obesity. Both pre‐obesity and obesity increased with age up to the age range brackets of 40 to 49 or 50 to 59 years for both men and women. Both pre‐obesity and obesity prevalence estimates were remarkably similar to data for Mexican Americans from 1982 through 1984. Comparison with other large surveys showed that countries differed more in the prevalence of obesity than of pre‐obesity, leading to differences in the PreOB/OB ratio, and that countries also differed in the gender ratio (female/male) for both pre‐obesity and obesity. Discussion: Pre‐obesity and obesity were high in our population and increased with age. Our approach of characterizing large surveys by PreOB/OB and gender ratios appeared promising.     

Prevalence and Covariates of Obesity in Lebanon: Findings from the First Epidemiological Study

Objective: To estimate the prevalence of overweight and obesity and examine associated covariates in the Lebanese population. Research Methods and Procedures: A cross‐sectional survey of a representative sample of 2104 individuals, 3 years of age and older. Anthropometric measurements and dietary assessments were conducted following standard methods and techniques. Overweight and obesity (classes I to III) were defined according to internationally standardized criteria for classification of BMI. Results: For children 3 to 19 years of age, prevalence rates of overweight and obesity were higher overall for boys than girls (22.5% vs. 16.1% and 7.5% vs. 3.2%, respectively). For adult men and women (age ≥ 20 years), the prevalence of overweight was 57.7% and 49.4%, respectively. In contrast, obesity (BMI ≥ 30 kg/m²) was higher overall among women (18.8%) than men (14.3%), a trend that became more evident with increasing obesity class. BMI, percentage of body fat, and waist circumference increased to middle age and declined thereafter. Whereas lack of exercise associated significantly with obesity among children, obesity in older adults was more prevalent among the least educated, nonsmokers, and those reporting a family history of obesity. Discussion: The results from this national population‐based study in Lebanon show high prevalence rates of overweight and obesity comparable with those observed in developed countries such as the United States. While further studies are needed to examine the underlying social and cultural factors associated with lifestyle and nutritional habits, now is the time to institute multicomponent interventions promoting physical activity and weight control nationwide.     

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.     

Evidence of Shared Genetic Effects Between Pre‐ and Postobesity Epidemic BMI Levels

United States has experienced a widespread obesity epidemic. However, it is unclear whether the obesogenic environment has uncovered genes previously unimportant in adiposity or whether genes influencing obesity are the same before and after the obesity epidemic. The objective of this study was to test whether BMI pre‐ and postobesity epidemic would be controlled by shared genetic effects. A 25–30‐year follow‐up of parents and children who participated in the National Institutes of Health–National Heart, Lung, and Blood Institute Lipid Research Clinics (LRC) Princeton School Study, 1973–1976, were followed up in 1999–2004 in the Princeton Follow‐up Study (PFS). Heritability of BMI and genetic correlations between pre‐epidemic BMI and BMI z‐scores in adolescents and postobesity epidemic BMI were calculated. Even though they had similar ages, offspring had higher BMI in PFS than their parents in LRC (28.5 ± 6.6 vs. 26.1 ± 4.4, P < 0.0001). BMI measurements in offspring were strongly heritable (BMI_LRC: h² = 0.78 ± 0.17; BMI z‐score_LRC: h² = 0.61 ± 0.16; BMI_PFS: h² = 0.64 ± 0.16, all P ≤ 0.0001). Further, the change of BMI exhibited a high heritability (h² = 0.51 ± 0.18, P = 0.003). Bivariate analysis of BMI in LRC and PFS showed significant genetic correlation (0.70 ± 0.16, P = 0.005), whereas the environmental correlation was not significant (0.36 ± 0.17). Although the obesogenic environment may have changed between the 1970s and 2000s, many of the same genes are likely to be involved in establishing genetic susceptibility to obesity. Furthermore, shared genetic effects survive the period of the transition from adolescence to adulthood.     

Trends in Height and BMI of 6‐Year‐Old Children during the Nutrition Transition in Chile

Objective: We analyzed trends in height and BMI and their interaction in 6‐year‐old Chilean children over the last 15 years. Research Methods and Procedures: We calculated height for age z‐score (HAZ), BMI z‐score, prevalence of obesity, underweight, and stunting from cross‐sectional national school‐based annual population surveys in 1987, 1990, 1993, 1996, 2000, and 2002. Using mixed model analysis, we determined the risk of obesity according to height over time as odds ratios (ORs) and 95% confidence interval and the potential influence of height and year of study on BMI z‐score. Results: Over the study period, height increased by 2.8 cm in boys and 2.6 cm in girls, whereas stunting declined from 5% to 2% in both. Tallness increased by ～2%, BMI z‐score increased from +0.3 to +0.65 in boys and to +0.62 in girls, and HAZ increased from ?0.47 in boys and ?0.45 in girls to 0 in 2002. Underweight declined from 4% to 3%, whereas obesity rose from 5% to ～14%. The probability of obesity among tall children was significantly greater than that for normal height children (OR, 2.3 to 3.5). The lowest obesity risk was observed between ?2 and ?1 HAZ. The OR for obesity in the stunted relative to normal height children was variable, ranging from 1.23 to 0.65, whereas it was significant and consistently positive (1.1 to 1.7) for boys and girls when it was compared with the lowest obesity risk according to height. Discussion: Tallness is significantly associated with increased obesity risk in children, while stunting is also associated, but to a lesser degree.     

Reducing overweight through a multidisciplinary school-based intervention

Objective: This study sought to evaluate the effectiveness of a multidisciplinary elementary school—based intervention entitled Wellness, Academics & You. The primary areas of impact examined were BMI, consumption of fruits and vegetables, and physical activity. Research Methods and Procedures: The sample consisted of 1013 students in fourth and fifth grades from 69 classes in four states. Intervention and comparison classes were randomly selected at each school. Intervention teachers participated in workshops on the intervention and received program materials. BMI was calculated for baseline and post‐data points based on measured height and weight collected by trained research teams. Baseline surveys were administered by the students’ teacher in the presence of one of the research team members and collected. Results: SPSS (SPSS, Inc., Chicago, IL) analysis of post‐data shows significant positive shifts (p = 0.01) in BMI in the intervention group compared with the comparison group. Notable increases in the consumption of fruits and vegetables and increased physical activity levels were reported in the intervention group. Discussion: Data from this study indicate that this school‐based program may contribute to the reduction of overweight and obesity. The intervention was well received by the classroom teachers and shows promise for a school‐based obesity prevention initiative. This program has shown the capacity to effect positive changes in BMI through consumption of fruits and vegetables and physical activity. The evaluation covered a limited time period and, therefore, warrants additional studies to determine whether long‐term program fidelity will result in continued improvement.     

Climate amenity and BMI

Objectives: Our goal was to examine the relationship between BMI and climate amenable for physical activity at the county level in the U.S. Research Methods and Procedures: Using Geographic Information Systems tools and 6‐year National Oceanic and Atmospheric Administration station hourly weather records, an index of amenable climate was derived for all U.S. counties. This index was linked to individual BMI in a multi‐level analysis that accounted for other individual characteristics from the 2002 survey of the Behavioral Risk Factor Surveillance System. Results: There was an inverse relationship between climate amenable to physical activity and BMI at the county level after controlling for individual risk factors, county road density, and median household income and unemployment rate. Residents in high climate‐amenity counties tended to have a lower BMI. Discussion: The contribution of less amenable climate to overweight and obesity in the U.S. is likely to be substantial because it cuts across wide geographic areas. Health promotion strategies that promote mixed land use or other urban design conducive to walking and other physical activities should consider broader environmental disamenities to mitigate their influence. Strategies for outdoor physical activity should also be tailored for people of different racial groups and educational backgrounds due to observed differences in their response to climate amenity.     

Dramatic Rise in Overweight and Obesity in Adult Filipino Women and Risk of Hypertension

Objective:To assess trends in BMI of adult Filipino women over a 16‐year period of rapid socioeconomic change; to identify factors associated with those trends; and to estimate the risk of hypertension associated with overweight, obesity, and high waist‐to‐hip ratio (WHR). Research Methods and Procedures:Women from randomly selected urban and rural communities of Metro Cebu, Philippines were recruited during a 1983 to 1984 index pregnancy, then followed prospectively for 16 years. Overweight and obesity were defined using BMI cut‐off points of 25 and 30, respectively. The analysis sample included women 15 to 45 years of age when measured 4 months postpartum. Weight change in subsequent intervals from 1985 to 1999 was modeled using linear regression. The relationship of BMI and WHR to risk of hypertension in the last survey was modeled using logistic regression. Results:The prevalence of overweight and obesity combined increased nearly 6‐fold from ～6% in 1983 to 1984 to 35% in 1998 to 1999. Weight gain was positively associated with urban residence, improved socioeconomic status, fewer pregnancies and months of lactation, and more away‐from‐home work hours. Risk of hypertension was independently elevated by high WHR and overweight/obesity. Discussion:The dramatic trend of increasing overweight and obesity in this sample of women represents a serious health concern, especially in light of the strong association of excess weight, particularly in the truncal region, to risk of hypertension.     

Cross‐Sectional and Longitudinal Associations between Body Mass Index and Marriage‐Related Factors

Objective: To assess the relationship between marriage and obesity. Research Methods and Procedures: Cross‐sectional and longitudinal associations were examined between participant body mass index (BMI), spouse BMI, and participant diet and exercise habits. Results: Spouse and participant BMI and BMI changes over 2 years were significantly associated. Participant BMI was associated with higher consumption of calorie‐dense foods and lower frequency of physical activity. Participants’ eating and exercise habits were only weakly related to spouse BMI. BMI did not predict the likelihood of marriage or divorce. However, marriage was associated with a significant 2‐year weight gain and divorce with a significant 2‐year weight loss. Discussion: The results suggest that spouse similarity in BMI is at least partly due to shared environment. The observed effects of marriage and divorce on weight may be due to the influence of marriage on inducements to eat (e.g., shared meals) or on motivation for weight control.     

Trends in the Association between Obesity and Socioeconomic Status in U.S. Adults: 1971 to 2000

Objective: To study the secular trends in the disparity of obesity across socioeconomic status (SES) groups among U.S. adults. Research Methods and Procedures: We used national representative data collected in the National Health and Nutrition Examination Surveys conducted in 1971 to 1974, 1976 to 1980, 1988 to 1994, and 1999 to 2000 from 28, 543 adults 20 to 60 years old. Obesity was defined based on BMI calculated using measured weight and height. Trends in the relationship between obesity and education levels were analyzed controlling for age, gender, and ethnicity. Results: The disparity in obesity across SES (less than high school, high school, and college or above to indicate low, medium, and high SES, respectively) has decreased over the past 3 decades. In National Health and Nutrition Examination Surveys I (1971 to 1974), there was as much as a 50% relative difference in the obesity prevalence across the three groups, but by 1999 to 2000, it decreased to 14%. This trend was more pronounced in women. The trends of diminishing disparities in obesity were also revealed by our logistic and linear regression analyses. The odds ratio converged to 1 from the 1970s to 2000. In most sociodemographic groups, the relationship between BMI and SES (coefficients) has been weakened over time. Discussion: The association between SES and obesity has been weakened over the past 3 decades, when the prevalence of obesity increased dramatically. There are considerable variations in the changes in the associations across gender and ethnic groups. Our findings suggest that individual characteristics are not likely the main cause of the current obesity epidemic in the U.S., whereas social‐environmental factors play an important role. Strategies for obesity prevention and management should target all SES groups from a societal perspective.     

Girls' perception of neighborhood factors on physical activity, sedentary behavior, and BMI

Objective: The purpose of this study was to examine the association of perceived physical neighborhood factors with physical activity, sedentary behavior, and BMI among adolescent girls. Research Methods and Procedures: Sixth grade girls (n = 1554) completed a questionnaire on neighborhood factors (e.g., safety, esthetics, access to physical activity resources). The dependent variables included non‐school metabolic equivalent weighted moderate to vigorous physical activity (MW‐MVPA) and non‐school sedentary behavior, both measured using accelerometry, and BMI. Results: The following neighborhood factors were associated with lower BMI: seeing walkers and bikers on neighborhood streets, not having a lot of crime in the neighborhood, seeing other children playing outdoors, having bicycle or walking trails in the neighborhood, and access to physical activity facilities. The absolute contribution for the average girl for each of these neighborhood factors was relatively small, with none of these factors exceeding 0.8 kg/m² BMI units. The following neighborhood factors were associated with higher MW‐MVPA: having well‐lit streets at night, having a lot of traffic in the neighborhood, having bicycle or walking trails in the neighborhood, and access to physical activity facilities. Girls with ≥9 places to go for physical activity had 14.0% higher non‐school MW‐MVPA than girls with ≤4 places. Discussion: This study identified several neighborhood factors associated with non‐school MW‐MVPA and BMI, but none of the factors explored were associated with non‐school sedentary behavior. Of all of the neighborhood factors we examined, reporting more physically active destinations contributed the largest absolute amount to the average girl's non‐school MW‐MVPA, according to this cross‐sectional study.     

Sugar‐Added Beverages and Adolescent Weight Change

Objectives : The increase in consumption of sugar‐added beverages over recent decades may be partly responsible for the obesity epidemic among U.S. adolescents. Our aim was to evaluate the relationship between BMI changes and intakes of sugar‐added beverages, milk, fruit juices, and diet soda. Research Methods and Procedures : Our prospective cohort study included >10, 000 boys and girls participating in the U.S. Growing Up Today Study. The participants were 9 to 14 years old in 1996 and completed questionnaires in 1996, 1997, and 1998. We analyzed change in BMI (kilograms per meter squared) over two 1‐year periods among children who completed annual food frequency questionnaires assessing typical past year intakes. We studied beverage intakes during the year corresponding to each BMI change, and in separate models, we studied 1‐year changes in beverage intakes, adjusting for prior year intakes. Models included all beverages simultaneously; further models adjusted for total energy intake. Results : Consumption of sugar‐added beverages was associated with small BMI gains during the corresponding year (boys: +0.03 kg/m² per daily serving, p = 0.04; girls: +0.02 kg/m², p = 0.096). In models not assuming a linear dose‐response trend, girls who drank 1 serving/d of sugar‐added beverages gained more weight (+0.068, p = 0.02) than girls drinking none, as did girls drinking 2 servings/d (+0.09, p = 0.06) or 3+ servings/d (+0.08, p = 0.06). Analyses of year‐to‐year change in beverage intakes provided generally similar findings; boys who increased consumption of sugar‐added beverages from the prior year experienced weight gain (+0.04 kg/m² per additional daily serving, p = 0.01). Children who increased intakes by 2 or more servings/d from the prior year gained weight (boys: +0.14, p = 0.01; girls +0.10, p = 0.046). Further adjusting our models for total energy intake substantially reduced the estimated effects, which were no longer significant. Discussion : Consumption of sugar‐added beverages may contribute to weight gain among adolescents, probably due to their contribution to total energy intake, because adjustment for calories greatly attenuated the estimated associations.