Significant Dose-Response Association of Physical Activity and Diet Quality With Mortality in Adults With Suspected NAFLD in a Population Study

INTRODUCTION: We aimed to determine whether higher levels (volume and intensity) of physical activity (PA) and diet quality (DQ) are associated with better survival rates in nonalcoholic fatty liver disease (NAFLD). METHODS: Using data from the 2011-2014 National Health and Nutrition Examination Survey, 3,548 participants with a Fatty Liver Index ≥60 were included. PA was collected using a wrist-worn triaxial accelerometer and expressed as 2 metrics using Monitor-Independent Movement Summary (MIMS) units: the average of daily MIMS, which represents volume, and peak 30-minute MIMS, which is the average of the highest 30 MIMS min/d and represents intensity. DQ was assessed by the Healthy Eating Index-2015. Mortality follow-up was recorded using the National Death Index linkage through December 31, 2019. RESULTS: Our analyses revealed a dose-dependent, nonlinear association of PA (volume and intensity) with all-cause mortality and a dose-dependent, linear association of DQ with all-cause mortality. The maximum protective dose of PA volume was observed at 14,300 MIMS/min (adj. HR: 0.20, 95% CI: 0.11-0.38). The maximum protective dose of PA intensity was observed at 54.25 MIMS/min (adj. HR: 0.10, 95% CI: 0.05-0.23), beyond which mortality risks flattened. The Healthy Eating Index-2015 showed its maximum protective effect at 66.17 (adj. HR: 0.54, 95% CI: 0.40-0.74). Higher PA (volume and intensity) levels were associated with a lower risk of cardiovascular-related but not cancer-related mortality. A healthier diet was linked to a reduced risk of cardiovascular-specific and cancer-specific mortality. Sensitivity analyses showed that the beneficial effects of PA and DQ on survival rates remained significant across sex, racial/ethnic, and age groups as well as in participants without NAFLD. DISCUSSION: Our findings suggest that higher daily accumulated and peak effort PA and DQ are associated with lower all-cause and cardiovascular mortality in US adults with NAFLD.