Physical activity compared to adiposity and risk of liver-related mortality: Results from two prospective, nationwide cohorts

BACKGROUND & AIMS: Obesity in adulthood has been associated with increased risk of liver-related mortality. Whether higher levels of physical activity counteract the excess risk conferred by obesity remains unknown. We simultaneously evaluated the long-term impact of physical activity and adiposity on liver-related mortality, within two nationwide populations. METHODS: We conducted a prospective cohort study of 77,238 women and 48,026 men, with detailed, validated assessments of weekly physical activity (metabolic equivalent task [MET]-hours]), adiposity (body mass index [BMI], waist circumference), and diet, alcohol use and clinical comorbidities, biennially from 1986 through 2012. Using Cox proportional hazards regression models, we calculated multivariable adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for liver-related mortality, including death from hepatocellular carcinoma (HCC) and other cirrhosis complications. RESULTS: Over 1,856,226 person-years, we recorded 295 liver-related deaths (108 HCC; 187 cirrhosis). Risk of liver-related mortality increased monotonically with higher BMI during adulthood (P(trend)3 hours/week could have prevented 25% of liver-related deaths (95%CI=0.12-0.38). CONCLUSIONS: In two prospective, nationwide cohorts, both excess adiposity and reduced PA were significant predictors of liver-related mortality. Achieving higher PA levels counteracted the excess liver-related risks associated with obesity.