Ecology of Obesity in West Philadelphia Adolescents

The prevalence of obesity among American children and adults has increased substantially over the past few decades. This research used an ecological framework to examine the relationships between biological, dietary, sociocultural and behavioral factors to determine how these factors influenced obesity status during adolescence in West Philadelphia. Correlates, values, and health risks of obesity were addressed. In Phase I of the study, obesity-related attitudes, anthropometric, dietary, and sociodemographic factors were measured for 392 West Philadelphia adolescents (11-15 years). Data were compared to two other groups of Philadelphia adolescents of comparable socioeconomic status and ethnic background measured in the 1960s and 1970s. Phase II was based on 32 matched-pairs of obese (BMI and triceps skinfold $\ge$95th percentile of NHANES I) and non-obese (BMI and triceps skinfold between the 15th and 85th percentiles of NHANES I) female adolescents selected from the Phase I sample based on obesity status and matched according to stature and age. Adolescents were compared on the following measures: physical activity, sedentary behavior, dietary intake, eating attitudes, health behavior knowledge, body image, self-esteem, and maturation status. Findings from Phase I include a threefold increase (males) and a fourfold increase (females) in the prevalence of obesity over the last two decades that was not concurrent with an increase in body fat centralization. The West Philadelphia adolescents had macronutrient intakes that were higher than the RDA and higher than age- and sex-specific data from NHANES III (Life Sciences Research Office, 1995). Micronutrient status was excellent, with the exception of calcium, zinc, fiber, and vitamins A and D. In Phase II, physical activity and television watching emerged as the most important contributory factors to obesity status. There were no statistically significant matched-pair differences in macronutrient and micronutrient intakes, self-esteem, eating attitudes, health behavior knowledge, body image, or maturation status of these adolescents. Findings indicate that sociocultural factors in the urban environment may promote obesity for these adolescents. This research suggests that future intervention strategies include attention to physical activity, television watching habits, and sociocultural factors in the urban environment

Quantile regression for mixed models with an application to examine blood pressure trends in China

Cardiometabolic diseases have substantially increased in China in the past 20 years and blood pressure is a primary modifiable risk factor. Using data from the China Health and Nutrition Survey, we examine blood pressure trends in China from 1991 to 2009, with a concentration on age cohorts and urbanicity. Very large values of blood pressure are of interest, so we model the conditional quantile functions of systolic and diastolic blood pressure. This allows the covariate effects in the middle of the distribution to vary from those in the upper tail, the focal point of our analysis. We join the distributions of systolic and diastolic blood pressure using a copula, which permits the relationships between the covariates and the two responses to share information and enables probabilistic statements about systolic and diastolic blood pressure jointly. Our copula maintains the marginal distributions of the group quantile effects while accounting for within-subject dependence, enabling inference at the population and subject levels. Our population-level regression effects change across quantile level, year and blood pressure type, providing a rich environment for inference. To our knowledge, this is the first quantile function model to explicitly model within-subject autocorrelation and is the first quantile function approach that simultaneously models multivariate conditional response. We find that the association between high blood pressure and living in an urban area has evolved from positive to negative, with the strongest changes occurring in the upper tail. The increase in urbanization over the last twenty years coupled with the transition from the positive association between urbanization and blood pressure in earlier years to a more uniform association with urbanization suggests increasing blood pressure over time throughout China, even in less urbanized areas. Our methods are available in the R package BSquare.Comment: Published at http://dx.doi.org/10.1214/15-AOAS841 in the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Food Availability/Convenience and Obesity

Neighborhood environments have received considerable attention in recent local, state, and national obesity prevention initiatives, with a particular focus on food deserts, or areas with poor access to healthy foods. Yet, there are inconsistencies in the evidence base, suggesting a nuanced association between neighborhood environment, food availability, diet behaviors, and obesity. There is heterogeneity in associations between environmental exposures and health outcomes across race/ethnicity, gender, region, and urbanicity, which results in complexity in the interpretation of findings. There are several limitations in the literature, including a predominance of cross-sectional studies, reliance on commercial business listings, lack of attention to the process by which diet resources are established and expanded within neighborhoods and the potential for individuals to selectively migrate to locate near such facilities, a predominant focus on residential neighborhoods, and lack of information about the decision-making process underlying purchasing patterns. More research is needed to address the complexity of individual-level residential decision making as well as the purposeful placement of food environment resources across social and geographic space using longitudinal data and complex statistical approaches. In addition, improvements in data quality and depth related to food access and availability are needed, including behavioral data on purchase patterns and interactions with the food environment, and greater attention to heterogeneity across subpopulations. As policy changes to the food environment move forward, it is critical that there is rigorous and scientific evaluation of environmental changes and their impact on individual-level diet choices and behaviors, and their further influence on body weight

The nutrition transition: Worldwide obesity dynamics and their determinants

OBJECTIVE: This paper explores the major changes in diet and physical activity patterns around the world and focuses on shifts in obesity. DESIGN: Review of results focusing on large-scale surveys and nationally representative studies of diet, activity, and obesity among adults and children. SUBJECTS: Youth and adults from a range of countries around the world. MEASUREMENTS: The International Obesity Task Force guidelines for defining overweight and obesity are used for youth and the body mass index ≥25 kg/m2 and 30 cutoffs are used, respectively, for adults. RESULTS: The nutrition transition patterns are examined from the time period termed the receding famine pattern to one dominated by nutrition-related noncommunicable diseases (NR-NCDs). The speed of dietary and activity pattern shifts is great, particularly in the developing world, resulting in major shifts in obesity on a worldwide basis. Data limitations force us to examine data on obesity trends in adults to provide a broader sense of changes in obesity over time, and then to examine the relatively fewer studies on youth. Specifically, this work provides a sense of change both in the United States, Europe, and the lower- and middle-income countries of Asia, Africa, the Middle East, and Latin America. CONCLUSION: The paper shows that changes are occurring at great speed and at earlier stages of the economic and social development of each country. The burden of obesity is shifting towards the poor

White Rice Intake Varies in Its Association with Metabolic Markers of Diabetes and Dyslipidemia Across Region among Chinese Adults

There are inconsistent associations between white rice consumption with diabetes and dyslipidemia, perhaps due to the nature of samples studied and quality of diet data

Where can they play? Outdoor spaces and physical activity among adolescents in U.S. urbanized areas

Objective—To estimate behavior-specific effects of several objectively-measured outdoor spaces on different types of moderate to vigorous physical activity (MVPA) in a large, diverse sample of U.S. adolescents. Methods—Using data from Wave I (1994–95) of the National Longitudinal Study of Adolescent Health (U.S., n=10,359) and a linked geographic information system, we calculated percent greenspace coverage and distance to the nearest neighborhood and major parks. Using sex-stratified multivariable logistic regression, we modeled reported participation in wheel-based activities, active sports, exercise, and ≥5 MVPA bouts/week as a function of each outdoor space variable, controlling for individual- and neighborhood-level sociodemographics. Results—Availability of major or neighborhood parks was associated with higher participation in active sports and, in females, wheel-based activity and reporting ≥5 MVPA bouts/week [OR (95% CI): up to 1.71 (1.29. 2.27)]. Greater greenspace coverage was associated with reporting ≥5 MVPA bouts/week in males and females [OR (95% CI): up to 1.62 (1.10, 2.39) for 10.1 to 20% versus ≤10% greenspace] and exercise participation in females [OR (95% CI): up to 1.73 (1.21, 2.49)]. Conclusions—Provision of outdoor spaces may promote different types of physical activities, with potentially greater benefits in female adolescents, who have particularly low physical activity levels

Ethnic Differences in Body Mass Index Trajectories from Adolescence to Adulthood: A Focus on Hispanic and Asian Subgroups in the United States

BackgroundCompared to whites, U.S. Hispanics have higher obesity rates; U.S. Asians have lower rates. However Hispanics and Asians are each comprised of several ethnic subgroups that differ with respect to country of origin, immigration history, and geographic distribution across the U.S. Among adolescents, ethnic differences in obesity have been previously reported, but no studies have examined longitudinal change in body mass index (BMI) by Hispanic and Asian subgroup category to understand when and why these disparities emerge, especially during the critical transition between adolescence and adulthood.MethodsUsing nationally-representative, longitudinal data from 1355 Hispanics (Mexican, Puerto Rican, Cuban, Central/South American, Other Hispanic), 520 Asians (Chinese, Filipino, Other Asian), and 5061whites from the National Longitudinal Study of Adolescent Health (Waves II–IV: 1996–2009), we used linear mixed spline models to examine whether Hispanic and Asian adolescent subgroups shared the same BMI trajectories as whites as they aged into adulthood. We also investigated the role of social and behavioral factors in explaining race/ethnic differences.ResultsAmong Hispanics, Mexican and Puerto Rican-origin individuals exhibited faster increases in BMI both in adolescence and in adulthood and these patterns were not attributable to the measured social and behavioral factors. There was also evidence of emerging disparities in Cuban males, and in Central/South Americans relative to whites. In contrast, Chinese, Filipino, and Other Asian adolescents had significantly lower BMI and slower BMI increases in adulthood compared to whites. In models adjusted for social and behavioral factors, Chinese-white and Other Asian-white differentials remained unexplained.ConclusionsAggregate estimates of Hispanics and Asians mask important heterogeneity in BMI. A better understanding of weight dynamics early in the life course can inform how and when disparities emerge to better target prevention efforts

Obesogenic Environments in Youth

To effectively prevent and reduce childhood obesity through healthy community design, it is essential to understand which neighborhood environment features influence weight gain in various age groups. However, most neighborhood environment research is cross-sectional, focuses on adults, and is often carried out in small, nongeneralizable geographic areas. Thus, there is a great need for longitudinal neighborhood environment research in diverse populations across the lifecycle. This paper describes: (1) insights and challenges of longitudinal neighborhood environment research and (2) advancements and remaining gaps in measurement and study design that examine individuals and neighborhoods within the context of the broader community. Literature-based research and findings from the “Obesity and Neighborhood Environment Database” (ONEdata), a unique longitudinal GIS that is spatially and temporally linked to data in the National Longitudinal Study of Adolescent Health (N=20,745), provide examples of current limitations in this area of research. Findings suggest a need for longitudinal methodologic advancements to better control for dynamic sources of bias, investigate and capture appropriate temporal frameworks, and address complex residential location processes within families. Development of improved neighborhood environment measures that capture relevant geographic areas within complex communities and investigation of differences across urbanicity and sociodemographic composition are needed. Further longitudinal research is needed to identify, refine, and evaluate national and local policies to most effectively reduce childhood obesity

Maturational timing and overweight prevalence in US adolescent girls

OBJECTIVES: This study examined the relation of age at menarche to overweight in US adolescent girls. METHODS: Effects of age at menarche and race/ethnicity on overweight were estimated via logistic regression, after adjustment for sociodemographic characteristics, in a sample of 6507 Hispanic, Black, White, and Asian American girls who participated in wave 2 of the National Longitudinal Study of Adolescent Health. RESULTS: Overweight prevalence rates were significantly higher in early maturing adolescents of all racial/ethnic groups but highest (57.5%) among early maturing Black girls. Early maturation nearly doubled the odds of being overweight (body mass index at or above the 85th percentile). CONCLUSIONS: Greater public health attention should be focused on the high prevalence of overweight, particularly among minority female adolescents

Socioeconomic gradients in body mass index (BMI) in US immigrants during the transition to adulthood: examining the roles of parental education and intergenerational educational mobility

Despite comparatively lower socioeconomic status (SES), immigrants tend to have lower body weight and weaker SES gradients relative to U.S.-born individuals. Yet, it is unknown how changes in SES over the life-course relate to body weight in immigrants versus US-born individuals