Study data published in the American Journal of Gastroenterology underline the role of physical activity in mitigating the risk for nonalcoholic fatty liver disease (NAFLD). In a prospective cohort of adults in the Netherlands, physical activity was inversely associated with NAFLD prevalence, with greater effects observed with higher activity intensity. These findings emphasize the relevance of physical activity in NAFLD management and prevention programs.
Investigators conducted a cross-sectional study within the Rotterdam Study, an ongoing prospective population-based cohort of adults aged 45 years and older living in Rotterdam, the Netherlands. The present analysis included all patients who participated in both the abdominal ultrasound and physical activity monitoring program between March 2009 and June 2014. Exclusion criteria were secondary risk factors for liver steatosis, including excessive alcohol consumption, hepatitis B and C, and steatogenic drug use.
Abdominal ultrasound was performed by a single experienced sonographer; the presence of steatosis on ultrasound constituted a diagnosis of NAFLD. During the activity monitoring phase, participants were instructed to wear a triaxial accelerometer continuously for 1 week. The accelerometer captured physical activity duration and intensity.
Physical activity was stratified into 4 intensity categories: sedentary, light, moderate, and vigorous. Logistic regression models were used to assess the impact of physical activity on risk for NAFLD, expressed as an odds ratio (OR). Models were adjusted for age, sex, educational attainment, smoking status, alcohol consumption, and certain metabolic factors, including fasting blood glucose, insulin resistance, and waist circumference.
The final study cohort consisted of 667 individuals of mean age 63.3±6.3 years, among whom 53% were women. Overall, 34.3% of participants had NAFLD. Total physical activity was associated with lower NAFLD prevalence. Specifically, for each 10-minute increase in daily physical activity, the likelihood of NAFLD diagnosis decreased (OR, 0.958; 95% CI, 0.929-0.986). More intense physical activity had a stronger effect on NAFLD risk; each 10-minute daily increase in vigorous physical activity constituted an OR of 0.740 (95% CI, 0.600-0.906) compared with sedentary time. The ORs for light and moderate activity were 0.931 (95% CI, 0.882-0.982) and 0.891 (95% CI, 0.820-0.967) per 10 minutes per day, respectively.
The association between physical activity and NAFLD was significantly attenuated after adjusting for components of metabolic health. Specifically, most of the observed effects of physical activity on NAFLD prevalence were explained by waist circumference (proportion mediated: 1.08; P <.001) and the homeostatic model assessment of insulin resistance (proportion mediated: 0.59; P <.001).
In this population-based cohort study, physical activity as measured with an accelerometer was inversely associated with risk for NAFLD. Study limitations include the cross-sectional design and the use of ultrasound, rather than biopsy, to diagnose NAFLD. However, liver biopsy is not ethical or feasible in a healthy study population due to the risk for complications.
“[W]e have demonstrated that physical activity is associated with a lower prevalence of NAFLD, which was mediated by better metabolic health, particularly lower waist circumference and better glucose management,” investigators wrote. “Although we observed strongest associations for vigorous physical activity, additional benefits were objectified for both moderate and light physical activities. This is especially relevant for those unable to reach vigorous physical activity and indicates that increasing time spent in lower intensities of physical activity may already be beneficial in achieving or maintaining good liver health.”
Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
van Kleef LA, Hofman A, Voortman T, de Knegt RJ. Objectively measured physical activity is inversely associated with nonalcoholic fatty liver disease: the Rotterdam study. Am J Gastroenterol. 2022;117(2):311-318. doi: 10.14309/ajg.0000000000001584