Factors Affecting Obesity and Waist Circumference Among US Adults

Physical activity, sedentary activity, and food intake affect waist circumference and obesity among adults; however, the relationship is unclear. The objective of our study was to explore how these factors affect waist circumference and obesity prevalence among adults.

We used cross-sectional data from the National Health and Nutrition Examination Survey 2013-2014 on 4,118 adults, 49% men and 51% women, aged 20 to 64 (mean age, 42). Weighted logistic regression models were fitted for abdominal obesity or obesity status and adjusted for variables of demographic characteristics, food intake, types of physical and sedentary activity, television and video viewing, and computer use. Analyses were stratified by sex.

Of the 4,118 people studied, 39% were obese (body mass index ≥30) and 55% had a high-risk waist circumference (hereinafter, abdominal obesity: men, ≥120 cm; women, ≥88 cm). People who watched television or videos 2 hours or more per day had increased odds of being abdominally obese (men, odds ratio [OR], 1.96; 95% confidence interval [CI], 1.29%-2.98%; women, OR, 1.66; 95% CI, 1.06%-2.59%) or obese (men, OR, 2.17; 95% CI, 1.18%-4.02%; women, OR, 1.66; 95% CI, 1.12%-2.48%). After adjusting for types of physical activity, associations remained significant only among men. Moderate recreational physical activity for 150 minutes or more a week versus 149 minutes or less was associated with reduced odds of abdominal obesity for both men (OR, 0.44; 95% CI. 0.22%-0.89%) and women (OR, 0.98; 95% CI, 0.23%-0.67%). Consuming meals prepared away from home was associated with high odds of obesity among women (OR, 1.67; 95% CI, 1.08%-2.58%).

Watching television and videos was positively associated with prevalence of abdominal obesity and obesity among men and women. Prevalence remained significant only among men with inclusion of physical activity. Further study is needed of the differences between the sexes in how physical and sedentary activity and food consumption are associated with obesity.