Interrelationship between physical activity and depression in nonalcoholic fatty liver disease

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is associated with a sedentary lifestyle and depressive symptoms. It is also well established that physical inactivity and depressive symptoms are related. However, an investigation of the interaction between all of these factors in NAFLD has not been previously conducted. AIM: To investigate the interrelationship between physical inactivity and depressive symptoms in individuals with NAFLD. METHODS: Data from the Rancho Bernardo Study of Healthy Aging were utilized. 589 individuals were included in the analyses (43.1% male; 95.8% non-Hispanic white; aged 60.0 ± 7.0 years). NAFLD was defined by using the hepatic steatosis index, depression using the Beck Depression Inventory, and physical activity by self-report of number of times per week of strenuous activity. Multivariable generalized linear regression models with Gamma distribution were performed to investigate the proposed relationship. RESULTS: About 40% of the sample had evidence of NAFLD, 9.3% had evidence of depression, and 29% were physically inactive. Individuals with NAFLD and depression were more likely to be physically inactive (60.7%) compared to individuals with neither NAFLD nor depression (22.9%), individuals with depression without NAFLD (37.0%), and individuals with NAFLD without depression (33.3%). After accounting for various comorbidities (i.e., age, sex, diabetes, hypertension, obesity), individuals with NAFLD and higher levels of physical activity were at a decreased odds of having depressive symptoms [16.1% reduction (95% confidence interval: -25.6 to -5.4%), P = 0.004], which was not observed in those without NAFLD. CONCLUSION: Individuals with NAFLD have high levels of physical inactivity, particularly those with depressive symptoms. Because this group is at high risk for poor outcomes, practitioners should screen for the coexistence of depressive symptoms and NAFLD. This group should receive appropriate interventions aimed at increasing both participation and levels of intensity of physical activity.