Association of physical activity and dietary inflammatory index with overweight/obesity in US adults: NHANES 2007-2018

Background: Overweight and obesity lead to a range of noncommunicable diseases (NCDs), such as type 2 diabetes, cardiovascular disease, and stroke. Physical activity (PA) is an important lifestyle behavior for controlling body weight. Dietary inflammatory index (DII), which is associated with systemic inflammatory markers, is used to evaluate the potential of dietary inflammation. This is the first study to investigate the independent and joint associations of PA and DII with the risk of overweight/obesity among US adults. Methods: Participants and data were obtained from the National Health and Nutrition Examination Survey (NHANES) from 2007- 2018, which is designed to examine the health and nutritional status of the non-institutionalized US population by a complex, multiResults: A total of 10723 US adults were selected. Physically active participants had lower overweight/obesity risk (total-time PA: OR = 0.756, 95% CI: 0.669-0.855; leisure-time PA: OR = 0.723, 95% CI: 0.643-0.813; and walk/bicycle-time PA: OR = 0.748, 95% CI: 0.639-0.875); however, those with work-time PA showed no significant association between PA and overweight/obesity. Compared with participants in the lowest DII group (Q1), those in the other three groups had high risks of overweight/obesity (Q2: OR = 1.218, 95% CI: 1.054-1.409; Q3: OR = 1.452, 95% CI: 1.245-1.693; Q4: OR = 1.763, 95% CI: 1.495-2.079). In joint analyses, PA was not eligible for reducing risks of weight/obesity if far more pro-inflammatory diet (Q4 of DII = 2.949-5.502) was taken in (total-time PA: OR = 1.725, 95% CI: 1.420-2.097; leisure-time PA: OR = 1.627, 95% CI: 1.258-2.105; walk/bicycle-time PA: OR = 1.583, 95% CI: 1.074-2.332; and work-time PA: OR = 1.919, 95% CI: 1.493-2.467). Conclusions: More leisure-time PA and walk/bicycle-time PA are associated with lower risk of overweight/obesity, and higher DII is associated with higher risk of overweight/obesity. In addition, higher DII impacts overweight/obesity substantially: once the DII score reached Q4, there is still risks of overweight/obesity even if PA is performed.