The Influence of Hobby Engagement on Cognitive Function Among Older Adults: A Population-Based Cohort Study Using Statistical Analysis and Machine Learning Predictions

BACKGROUND: Cognitive decline is an escalating public health challenge with global population aging. Understanding the association between hobby engagement and cognitive function is crucial for developing effective interventions. METHODS: Utilizing data from waves 2 to 9 of the English Longitudinal Study of Ageing (ELSA), this study included 6854 community-dwelling adults aged 50 years and older. To comprehensively capture this relationship, we employed a multi-method analytical approach, encompassing multiple linear regression, linear mixed-effects models, group-based trajectory modeling (GBTM), and a comparison of machine learning algorithms to assess both associations and predictive performance. RESULTS: Cross-sectionally, hobby engagement was significantly associated with higher baseline global cognitive, memory, and executive function scores. Longitudinally, hobbies were associated with a slower rate of decline in orientation, but not in memory, executive function, or global cognition. Group-based trajectory modeling, which identifies distinct subgroups with heterogeneous cognitive pathways, revealed that hobby engagement was associated with a substantially lower risk of belonging to a "persistently low cognitive function" trajectory (OR = 0.46). Among predictive models, the Scikit-learn Gradient Boosting Regressor demonstrated superior performance (RMSE = 0.7517, R² = 0.3033), outperforming deep learning approaches. CONCLUSIONS: Our findings suggest that hobby engagement may have domain-specific protective effects on cognitive health in older adults, most notably by drastically reducing the risk of a severely adverse cognitive trajectory. Promoting hobby participation therefore emerges as a potential viable, low-cost, and impactful public health strategy for preserving cognitive health in aging populations.