Non-alcoholic fatty liver disease (NAFLD) is associated with low level of physical activity: a population-based study

Background: High intensity exercise improves metabolic status and may potentially mobilise hepatic fat.

Aim: To assess the level of physical activity (PA) of subjects with non-alcoholic fatty liver disease (NAFLD).

Methods: Data were obtained from NHANES (2003-2006). Activity counts obtained from accelerometer readings (ActiGraph, Fort Walton Beach, FL), from 7 consecutive days quantified total PA and time spent engaged in different levels of activity. All measures were counts/minutes/day: (sedentary <100; light 100-0027; moderate, 2020-5999 and vigorous, 6000+). NAFLD was defined as a fatty liver index >60 (FLI) in the absence of other chronic liver disease. Subjects with NAFLD were compared to controls using stratum-specific Chi-squared and t-tests. Simple linear regression analyses (with Taylor series linearised variance estimation and weighting) were used to determine the association between PA levels and NAFLD. P-values <0.05 were considered significant. Statistical analyses were conducted using sudaan version 10.1 and sas version 9.1.

Results: We included 3056 participants. NAFLD patients were older, had higher BMI, larger waist circumference, higher sum of skinfolds, more likely to have insulin resistance (HOMA > 3.0) and type-2 diabetes (all P-values <0.01). Average PA for NAFLD subjects was about 28.7 counts/minute/day less than controls (P < 0.01). Furthermore, NAFLD subjects spent less time participating in activity at any level (P < 0.01). Subjects with NAFLD and DM were in the lowest quartile of average PA as well as moderate-vigorous PA (P < 0.01).

Conclusions: Data from this study show that non-alcoholic fatty liver disease patients have low level of physical activity and, when they have diabetes mellitus, they perform at the lowest quartile of physical activity and moderate-vigorous physical activity.