Essays on the Effect of Environmental Factors on Health Choices and Health Behavior of Individuals

Abstract

Understanding the causes of spread of obesity is important to address public health concern and formulate public policy. Causally identifying factors that influence the spread of obesity is difficult. Specifically, it is difficult to disentangle the contextual effects or environmental factors that drive weight gain in individuals from the self-selection of individuals into groups that share common, potentially unobserved, characteristics. In my first paper I tried to disentangle these competing explanations by collecting data from a unique population of international students. I surveyed international graduate students at 48 public universities across the United States. I used this data to investigate the effect of obesity prevalence in a particular region on international students' weight gain. Results show that students studying in areas with a lower prevalence of obesity show a significantly lower increase in their weight compared to students studying in areas with a higher prevalence of obesity. In the second essay I used the restricted-use New Immigrant Survey 2003 data to study the association between surrounding environmental factors and BMI of recent immigrants to the United States. Immigrants also offer a unique opportunity to disentangle the self-selection and contextual effects while studying the effect of environmental factors on the weight gain in individuals. I find statistically significant effects on the immigrants' BMI levels. Immigrants residing in areas with lower prevalence of obesity have significantly lower BMI levels compared to those residing in areas with higher prevalence of obesity. Results show that dietary change in immigrants is influenced by the local environmental factors and that dietary change affects the BMI levels of the immigrants. The third essay is an intervention study to promote physical exercise among freshman students at a university in the Midwest. I investigated the effect of social norming and financial incentives on promoting physical exercise among randomly selected freshman students. Through the third essay, I investigate the effectiveness of two policies that have been proven to modify individual behaviors in encouraging healthy behavior.