Association of physical activity and sedentary time with risk of non-alcoholic fatty liver disease in adults with and without diabetes mellitus

This study examined the association of physical activity (PA) and sedentary time (ST) with the risk of non-alcoholic fatty liver disease (NAFLD) in adults with and without diabetes mellitus (DM). The study used data from the 2017-2020 National Health and Nutrition Examination Survey and conducted weighted logistic regression analysis to examine the association between PA, ST and NAFLD risk in individuals with and without DM. A total of 4,805 participants were included, with a weighted prevalence of NAFLD of 36% and a weighted prevalence of DM of 13.3%. Participants were divided into quartiles (Q1-Q4) based on PA levels (MET-min/week) and ST (min/day), with Q1 representing the lowest activity/shortest sitting time. In the total population, for PA, the risk of NAFLD in the Q2 and Q3 groups was reduced by 0.593 and 0.660 times, respectively, compared with the Q1 group. For ST, relative to the Q1 group, the NAFLD risk increased in the Q2, Q3 and Q4 groups by 1.420, 1.361 and 1.690 times, respectively. The dose-response analysis revealed that in the total population, NAFLD risk decreased when PA levels were between 1,553.4 and 30,402.3 metabolic equivalent of task (MET)-min/week (p_non-linear = 0.016). Among individuals without DM, for PA, the NAFLD risk in the Q2 and Q3 groups was 0.571 and 0.648 times lower, respectively, than that in the Q1 group. When PA was within the range of 1,775.3 to 24,410.6 MET-min/week, the risk of NAFLD was reduced (p_non-linear = 0.033). Patterns of association between PA, ST, and NAFLD appeared to differ between individuals with and without DM; however, multiplicative interaction terms were not statistically significant.