UCSF

Background: Given the obesity epidemic across communities and countries worldwide, being overweight and obesity among adolescents has become a critical public health concern. Overweight and obesity in adolescence are known to negatively affect on an individual’s physical, psychological, and social status. It is imperative to identify not only individual-level factors but also social-environmental factors that influence physical activity, dietary intake, and body weight in order to reduce disparities in obesity.

Objectives: Using a social-ecological framework, the aims of this dissertation were: 1) to assess the contribution of social-ecological factors to regular physical activity; 2) to explore determinants associated with dietary patterns; 3) to estimate prevalence of overweight or obese, and to identify gender-specific risk factors for obesity among California adolescents.

Methods: The data was drawn from the California Health Interview Survey (CHIS). The first and third study included a total of 2,799 adolescents in the CHIS 2011-2012 data, and the second study included 4,000 adolescents from the CHIS 2011-2012, and 2013 datasets. Data examined included the individual-level (e.g., socio-demographics, body mass index percentile) and the neighborhood-level (e.g., availability of activity resources, food environment, safety) characteristics associated with physical activity, diet, and obesity.

Results: The first study found that those of the male sex, older teenagers, and having a higher household income were significant predictors for engaging in regular physical activity. The second study revealed that unhealthy dietary patterns (low consumption of fruits and vegetables, but high consumption of fast foods and sugary drinks) were found among adolescents from Hispanic or ethnic minorities, lower socioeconomic status, second or third generation immigrants, and in rural areas. The third research study demonstrated the gender-specific factors associated with a risk of overweight or obesity among adolescents. For girls, age, race/ethnicity, income, bitrhplace, physical activity, and neighborhood safety were significantly associated with being overweight or obese. In contrary, only age and race/ethnicity remain significant for boys.

Conclusion: The findings extends our understanding by identifying different features both at the individual and neighborhood level that are hypothesized to influence physical activity, diet, and obesity risk among adolescents. The findings of the dissertation suggest that a multilevel approach from a social-ecological perspective is crucial to implementing interventions/policies to effectively manage the obesity epidemic and to identify root causes of obesity disparities among adolescents.