Physical activity and diet on atherogenic index of plasma among adults in the United States: mediation considerations by central adiposity.

BACKGROUND/OBJECTIVES: The potential interactive or combined association of moderate-to-vigorous physical activity (MVPA) and dietary behavior with atherogenic index of plasma (AIP) has yet to be explored in a representative sample of US adults. Thus, the study aim was to examine the association of MVPA and dietary behavior on AIP, with potential mediation considerations by central adiposity.

SUBJECTS/METHODS: Data from the National Health and Nutrition Examination Survey were used (N = 2701 adults aged 20-85 years). AIP was evaluated via blood sample, MVPA was assessed via accelerometry, and two 24-h recalls were utilized to calculate Healthy Eating Index (HEI), a metric of dietary quality. Android-specific dual energy X-ray absorptiometry (DXA) was used to measure central adiposity.

RESULTS: Meeting MVPA guidelines (OR = 0.58; 95% CI: 0.41-0.82; P = 0.004), but not meeting dietary guidelines (OR = 0.89; 95% CI: 0.69-1.15; P = 0.37), was associated with reduced odds of having an elevated (>0.24 mmol/L) AIP. Having one (OR = 0.68; 95% CI: 0.52-0.89; P = 0.007) or both (OR = 0.55; 95% CI: 0.37-0.82; P = 0.005) health-enhancing behaviors (adequate physical activity and/or healthy diet), when compared to having neither, was associated with reduced odds (32 and 45%) for having an elevated AIP. The relative excess risk due to interaction (RERI) was 0.06 (95% CI: -0.06 to 0.18; P = 0.31), suggesting there is no additive interaction between MVPA and dietary behavior on AIP. All associations were attenuated when including central adiposity as a covariate, suggesting a mediation effect of central adiposity.

CONCLUSIONS: MVPA is independently associated with reduced odds of having an elevated AIP, having both adequate levels of MVPA and a healthy diet does not substantively reduce the odds of AIP, and there is no additive interaction effect between MVPA and diet on AIP. Central adiposity mediated the relationship between MVPA and AIP.