Hobby engagement and all-cause and cause-specific mortality risk among people aged 50 years and older in 19 countries.

Background: Global population ageing necessitates identifying modifiable factors for healthy longevity. Hobby engagement emerges as a promising yet unexplored factor; evidence of its protective effects on all-cause and cause-specific mortality risk has never been examined at a multinational level. Methods: We investigated hobby engagement and mortality risk among 79 464 adults aged ≥50 across 19 countries using harmonised longitudinal ageing cohorts. Cox proportional hazards models examined associations between hobby engagement and all-cause mortality. Competing risk models assessed cause-specific mortality. Marginal structural models evaluated the impact of change patterns in hobby engagement over time. Results: Hobby engagement was associated with a 29% reduction in all-cause mortality risk across 19 countries (pooled hazard ratio (HR) = 0.71; 95% confidence interval (CI) = 0.67, 0.75). Population attributable fractions ranged from 3.03% (in Denmark) to 23.56% (in China), with potential gains in life expectancy from 0.06 years (in China) to 1.02 years (in Sweden) over five years. Region-specific protective effects emerged: reduced mortality from endocrine/metabolic (subhazard ratio (SHR) = 0.31) and neurological conditions (SHR = 0.51) in the USA; cardiovascular mortality (SHR = 0.56) in England; and heart attack (SHR = 0.77), stroke (SHR = 0.62), other cardiovascular-related illnesses (SHR = 0.82), and respiratory disease (SHR = 0.68) in Europe. Hobby engagement patterns varied dramatically across countries, from predominant non-engagement in China (65.1%) to high sustained engagement in Northern Europe (>90%). Both initiating (pooled HR = 0.62) and sustaining (pooled HR = 0.45) hobby engagement were associated with a reduction in mortality risk compared to sustained non-engagement, while cessation eliminated these protective associations (pooled HR = 0.96; 95% CI = 0.88, 1.04). Benefits were more pronounced among adults aged ≥65 and married individuals. Conclusions: Hobby engagement is a potentially universal, modifiable factor for promoting global healthy longevity. Public health strategies prioritising initiating and maintaining hobby engagement could yield substantial survival benefits, particularly in countries with predominant non-engagement patterns and high preventable mortality.