Obesity ups liver-related mortality risk, exercise cuts it

Obesity appears to be a strong risk factor for liver-related mortality, while exercise exerts a protective effect, a recent study has found.

Drawing from two nationwide population samples, researchers conducted a prospective cohort study on 77,238 women and 48,026 men with detailed and validated assessments of weekly physical activity, as expressed in metabolic equivalent task (MET)-hours. Other important factors were body mass index (BMI), waist circumference, diet, alcohol use and clinical comorbidities.

Multivariable Cox proportional hazards regression analysis found that each unit increase in cumulative average BMI correlated with a significant 5.1-percent jump in the risk of liver-related mortality (p_trend<0.0001).

When taken according to categories, BMI 25 to <30 kg/m² (adjusted hazard ratio [HR], 1.40, 95 percent confidence interval [CI], 1.06–1.84), 30 to <35 kg/m² (adjusted HR, 2.22, 95 percent CI, 1.56–3.16), and ≥35 kg/m² (adjusted HR, 2.97, 95 percent CI, 1.84–4.79) were all significant risk factors for liver-related mortality than BMI 19 to <25 kg/m².

Central adiposity had a similar effect. Each additional cm in WC correlated with a 5.6-percent increase in the risk of liver-related mortality (p_trend=0.003). Participants in the highest WC quartile were twice as likely as their lowest-quartile comparators to die of liver-related causes (adjusted HR, 2.09, 95 percent CI, 1.16–3.77).

In contrast, exercise appears to counteract this risk. Each additional 3 MET-hours per week of exercise led to a 3.5-percent drop in the risk of liver-related mortality. This protective effect intensified with increasing physical activity (p_trend<0.0001).