Effect of Physical Activity on Obesity in Older American Adults over Fourteen Years

Physical activity (PA) is recognized as an effective behavioral intervention for controlling body weight. However, the public’s neglect of importance of PA likely contributes to the prevalence of obesity among older adults. This study analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 2005–2006 to 2017–2018 to examine the association between PA and obesity, and to identify trends and contribution of PA in older obese adults. A total of 5,812 obese participants were selected for association and trend analyses. Logistic regression was applied to estimate the associations between PA and obesity. Trend tests over 14 years were evaluated using orthogonal polynomial coefficients in a regression analysis. Students’ t-test was used to compare the slopes of the obesity trend and the PA trend. In two cycles (2005–2006 and 2017–2018), 1,461 participants were selected for Oaxaca-Blinder regression decomposition analysis to explain the contribution of PA to obesity over 14 years. Results revealed a significant negative correlation between PA and obesity in older adults, suggesting that increased participation in PA can reduce the likelihood of obesity (OR = 0.22, 95% CI=0.15-0.34, p = 0.00). From 2005 to 2018, the trend in PA closely paralleled the obesity trend. Notably, PA was identified as a contributing factor, accounting for 9% of the observed increase in obesity during this period. These findings can guide the development of targeted PA interventions aimed at reducing the widespread prevalence of obesity among older adults in the United States.