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

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

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

The Role of Adolescent Behaviors in the Female–Male Disparity in Obesity Incidence in US Black and White Young Adults

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93675/1/oby.2009.362.pd

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

Are neighbourhood food resources distributed inequitably by income and race in the USA? Epidemiological findings across the urban spectrum

ObjectiveMany recent policies focus on socioeconomic inequities in availability of healthy food stores and restaurants. Yet understanding of how socioeconomic inequities vary across neighbourhood racial composition and across the range from rural to urban settings is limited, largely due to lack of large, geographically and socio-demographically diverse study populations. Using a national sample, the authors examined differences in neighbourhood food resource availability according to neighbourhood-level poverty and racial/ethnic population in non-urban, low-density urban and high-density urban areas.DesignCross-sectional data from an observational cohort study representative of the US middle and high school-aged population in 1994 followed into young adulthood.ParticipantsUsing neighbourhood characteristics of participants in the National Longitudinal Study of Adolescent Health (Wave III, 2001–2002; n=13 995 young adults aged 18–28 years representing 7588 US block groups), the authors examined associations between neighbourhood poverty and race/ethnicity with neighbourhood food resource availability in urbanicity-stratified multivariable linear regression.Primary and secondary outcome measuresNeighbourhood availability of grocery/supermarkets, convenience stores and fast-food restaurants (measured as number of outlets per 100 km roadway).ResultsNeighbourhood race and income disparities were most pronounced in low-density urban areas, where high-poverty/high-minority areas had lower availability of grocery/supermarkets (β coefficient (β)=–1.91, 95% CI –2.73 to –1.09) and convenience stores (β=–2.38, 95% CI –3.62 to –1.14) and greater availability of fast-food restaurants (β=4.87, 95% CI 2.26 to 7.48) than low-poverty/low-minority areas. However, in high-density urban areas, high-poverty/low-minority neighbourhoods had comparatively greater availability of grocery/supermarkets (β=8.05, 95% CI 2.52 to 13.57), convenience stores (β=2.89, 95% CI 0.64 to 5.14) and fast-food restaurants (β=4.03, 95% CI 1.97 to 6.09), relative to low-poverty/low-minority areas.ConclusionsIn addition to targeting disproportionate fast-food availability in disadvantaged dense urban areas, our findings suggest that policies should also target disparities in grocery/supermarket and fast-food restaurant availability in low-density areas.Article summaryArticle focusUsing national data, we examined whether neighbourhood food resource availability exhibits joint race and socioeconomic inequities across levels of urbanicity.Key messagesSocio-demographic inequities in neighbourhood food resource availability were most pronounced in low-density urban (largely suburban) areas.In high-density urban areas, higher neighbourhood poverty was associated with greater availability of all food resources.Whereas policy has focused on dense urban settings, less urban areas might also benefit from policies addressing food access.Strengths and limitations of this studyWhile business records provide comparable data across the USA, these data may contain error and do not indicate availability of specific foods.National coverage enabled examination of the joint role of neighbourhood race and socioeconomic status across urban strata within a single study

Screen time and physical activity during adolescence: longitudinal effects on obesity in young adulthood

<p>Abstract</p> <p>Background</p> <p>The joint impact of sedentary behavior and physical activity on obesity has not been assessed in a large cohort followed from adolescence to adulthood.</p> <p>Methods</p> <p>Nationally representative longitudinal data from Waves II (1995; mean age: 15.9) and III (2001; mean age: 21.4) of the National Longitudinal Study of Adolescent Health (n = 9,155) were collected. Sex-stratified multivariate logistic regression analysis assessed the odds of obesity associated with Wave II MVPA and screen time, controlling for sociodemographic characteristics and change in MVPA and screen time from Wave II to III. Obesity was defined using body mass index (BMI, kg/m²) International Obesity Task Force cut-points at Wave II and adult cut-points at Wave III (BMI ≥ 30).</p> <p>Results</p> <p>In males, adjusted odds of prevalent obesity was strongly predicted by MVPA bouts [OR (95% CI): OR_{6 vs. 1 MVPA bouts}= 0.50 (0.40, 0.62); OR_{4 vs. 40 hrs screen time}= 0.83 (0.69, 1.00)]. In females, greater MVPA bouts and lower screen time correlated with lower prevalent obesity [OR (95% CI): OR_{6 vs. 1 MVPA bouts}= 0.67 (0.49, 0.91); OR_{4 vs. 40 hrs screen time}= 0.67 (0.53, 0.85)]. Longitudinally, adolescent screen time hours had a stronger influence on incident obesity in females [OR (95% CI): OR_{4 vs. 40 hrs}= 0.58 (0.43, 0.80)] than males [OR (95% CI): OR_{4 vs. 40 hrs}= 0.78 (0.61, 0.99)]. Longitudinal activity patterns were not predictive of incident obesity.</p> <p>Conclusion</p> <p>Reducing screen time during adolescence and into adulthood may be a promising strategy for reducing obesity incidence, especially in females.</p

Screen time and physical activity during adolescence: longitudinal effects on obesity in young adulthood

<p>Abstract</p> <p>Background</p> <p>The joint impact of sedentary behavior and physical activity on obesity has not been assessed in a large cohort followed from adolescence to adulthood.</p> <p>Methods</p> <p>Nationally representative longitudinal data from Waves II (1995; mean age: 15.9) and III (2001; mean age: 21.4) of the National Longitudinal Study of Adolescent Health (n = 9,155) were collected. Sex-stratified multivariate logistic regression analysis assessed the odds of obesity associated with Wave II MVPA and screen time, controlling for sociodemographic characteristics and change in MVPA and screen time from Wave II to III. Obesity was defined using body mass index (BMI, kg/m²) International Obesity Task Force cut-points at Wave II and adult cut-points at Wave III (BMI ≥ 30).</p> <p>Results</p> <p>In males, adjusted odds of prevalent obesity was strongly predicted by MVPA bouts [OR (95% CI): OR_{6 vs. 1 MVPA bouts}= 0.50 (0.40, 0.62); OR_{4 vs. 40 hrs screen time}= 0.83 (0.69, 1.00)]. In females, greater MVPA bouts and lower screen time correlated with lower prevalent obesity [OR (95% CI): OR_{6 vs. 1 MVPA bouts}= 0.67 (0.49, 0.91); OR_{4 vs. 40 hrs screen time}= 0.67 (0.53, 0.85)]. Longitudinally, adolescent screen time hours had a stronger influence on incident obesity in females [OR (95% CI): OR_{4 vs. 40 hrs}= 0.58 (0.43, 0.80)] than males [OR (95% CI): OR_{4 vs. 40 hrs}= 0.78 (0.61, 0.99)]. Longitudinal activity patterns were not predictive of incident obesity.</p> <p>Conclusion</p> <p>Reducing screen time during adolescence and into adulthood may be a promising strategy for reducing obesity incidence, especially in females.</p