Date of Award

Spring 5-7-2016

Degree Type


Degree Name

Master of Public Health (MPH)


Public Health

First Advisor

Dr. Richard Rothenberg

Second Advisor

Dr. Monica Swahn


Introduction: The prevalence of childhood and adolescent obesity in the U.S. and in other countries has continued to rise over the last several decades. Health behaviors such as physical activity and inactivity patterns have been shown to influence rates of obesity among adolescents. Racial/ethnic disparities related to adolescent obesity have been recognized through existing research, and differences in socioeconomic and cultural backgrounds have been noted as possible contributing factors to the risk of adolescents becoming overweight or obese. The primary purpose of this study was to analyze the association of physical activity and sedentary activity with obesity prevalence among adolescents aged 12-15 years old across ethnic groups in the U.S.

Methods: This study utilized data from the combined 2007-2012 National Health and Nutrition Examination Survey (NHANES). Descriptive characteristics of the study population were analyzed for both ethnicity and BMI status, and Chi-square tests were used to assess differences among the variables. The association between BMI status categories and ethnicity were evaluated. A univariate analysis was conducted to evaluate the association of the independent and covariate variables with obese status among adolescents. A multivariable logistic regression was also performed to determine the association between BMI status and physical activity, controlling for the covariate variables. For sedentary activity, the frequency statistics were analyzed between each of the ethnicities and BMI status, and t-tests were conducted to determine statistical significance.

Results: The sample size for this population included 939 adolescents. Approximately 40% of adolescents were categorized as obese, according to age- and sex-specific BMI percentiles. Among ethnicity, Non-Hispanic white adolescents had the greatest prevalence of obesity, compared to Non-Hispanic Black and Mexican-American adolescents. There was not significant association between BMI status and demographic characteristics, including ethnicity, in the sample. Regarding physical activity, there was some indication that those who engaged in moderate and vigorous physical activity were less likely to be obese, however these findings were not found to be significant. Non-Hispanic black obese adolescents reported significantly less moderate activity compared to Non-Hispanic white adolescents(p=0.02). Obese adolescents in this sample had reported slightly less mean sitting time per day, compared to those who were not obese.

Conclusion: Although the findings of this analysis showed some indication of differences in physical activity and sedentary behavior patterns among obese adolescents, the overall findings did not provide a statistically significant association between the variables and ethnicity. Further studies related to this topic could analyze differences in cultural and social norms across ethnicities that could influence physical activity behaviors in adolescents. Also, access to exercise facilities and differences in dietary behaviors among adolescents could be considered.