Weight and the Shape of Adolescents: Technology and Exercise

Adefunke Shonubi, MSW ‘17

George Warren Brown School of Social Work

Washington University in St Louis

Abstract

Background: Several studies have tried to find the association of high exposure to screen time, participation in physical activity with overweight and obesity among adolescents. However, these studies have revealed varying results.

Purpose: The purpose of this study is to describe the associations of physical activity and screen time (computer and TV) with overweight and obesity among a representative of high school students in US. The research question for this study is “Does sedentary behavior and physical activity have any association with obesity and overweight in adolescents?”. The hypotheses stated that exposure to computer and television, and participation in physical activity are each associated with overweight and obesity in high school students.

Methods: The study analyzed the cross-sectional survey data from the Youth Risk Behavior Surveillance Study (YRBSS) in 2015. This was a survey carried out in national high schools in 37 countries across the country. After cleaning the data and removing missing variables, a total of 11,618 students between grades 9 and 12 (out of the initial 15,624) were included in the study.

Measures: The independent variables included physical activity, computer time and TV time. Each of the responses to these questions were measured on a Likert scale response. Physical activity had a 0-7 scale response with 0 being exposed to physical activity for at least 60 minutes in 0 days and 7 for 7 days. Computer and TV time had a 0-5 scale response with 0 as response for no exposure and 5 for exposure for 5hours or more.

The dependent variables include overweight and obesity. These height and weight responses were used to calculate the Body Mass Index. Thereafter, using the CDC criteria, respondents whose BMI were >85 were grouped as overweight, while those whose BMI were >95 were grouped as obese.

Analysis: Using logistic regression models which controlled for age, sex, grade, fruit and vegetable intake, body weight was compared in students with different levels of exposure to television and computer. Chi-square was also used to analyze the control variables.

Results: Students who were physically active for more than 60 minutes were less likely to be overweight or obese. The longer students spend using or watching computers and television respectively, the higher their chances of being obese. The chi-square analysis shows strong correlations between computer time and age, sex and grade. However, these correlations were not seen in the analysis of television time.

Conclusion: In promoting health behavior and designing obesity prevention programs, there is a need to address physical activity and sedentary behavior jointly. The results may also be used to advocate for the review of making physical education classes a requirement in high schools.