Changes in alcohol intake, fitness, and all-cause mortality in the HUNT Study, Norway

Abstract Background There is no safe lower limit for alcohol intake, and even small amounts increase the risk of premature mortality. It is not known whether changes in cardiorespiratory fitness can modify the association between changes in alcohol intake and mortality. Methods We analyzed data from the Trøndelag Health Study (HUNT2: 1995-1997; HUNT3: 2006-2008). Alcohol intake was categorized as abstainers, within recommendations (140 g/week men, 70 g/week women), or above recommendations. Fitness was classified as unfit (20% least fit) or fit (80% most fit) using a validated prediction equation. Multivariable-adjusted Cox analyses estimated hazard ratios (aHRs) for all-cause mortality. Results Among 24,853 healthy adults (mean age 54.7 years; 54.1% women), 3,921 deaths occurred over a median follow-up of 16.6 years. Increased alcohol intake was associated with higher mortality risk. Abstainers who started drinking within recommendations (aHR 1.20; 95% CI 1.00-1.44) and those who exceeded recommendations (1.25; 0.99-1.57) had elevated mortality risks compared to persistent abstainers. Reducing alcohol intake to abstinence did not increase risk (1.14; 0.80-1.62). Fitness significantly modified the alcohol-mortality relationship (P = 0.03). Unfit individuals had higher mortality risks, with aHRs of 1.65 (persistent abstainers), 1.46 (started drinking), and 1.68 (consistent within recommendations) compared to the reference group (abstainers who remained fit). Maintaining high fitness attenuated mortality risks, except for those who started drinking (1.32; 1.04-1.68). Declining fitness increased mortality risk among persistent abstainers and consistent drinkers. Conclusions Increased alcohol intake over time was associated with higher mortality risk. However, maintaining high cardiorespiratory fitness attenuated this association, highlighting fitness as a stronger predictor of mortality. Key messages • Even small amounts of alcohol raise premature death risk. Regular physical activity may modify alcohol-mortality association, but it's unclear if changes in fitness affect this association. • Maintaining a high fitness lowers the mortality risk associated with alcohol intake, and a 10-year change in fitness is a better predictor of mortality than contemporary changes in alcohol intake.