Background: We evaluated the combined and differential effects of physical, social and productive activities on cognitive decline and whether they were modified by the presence of the APOE-epsilon 4 allele.
Methods: In a prospective cohort study of 1635 community-dwelling Chinese older adults aged 55 or older participating in the ongoing Singapore Longitudinal Aging Study, physical, social and productive leisure activities were assessed at baseline, and cognitive decline (at least one point drop) in MMSE scores between baseline and follow-up after one year.
Results: Cognitive decline was observed in 30% of the respondents. Controlling for age, gender, education and other risk factors, odds ratios (ORs) were significantly reduced in those with medium (OR: 0.60, 95% CI: 0.45-0.79) and high activity levels (OR: 0.62, 95% CI: 0.46-0.84). A stronger association was shown for productive activity (OR = 0.36), than for physical (OR = 0.78) and social activities (OR = 0.85). These associations showed statistically significant interactions with APOE genotype, being more pronounced in those with the APOE-epsilon 4 allele.
Conclusion: Increased leisure activity, especially productive activities more than physical or social activities, was associated with a lowered risk of cognitive decline. APOE-epsilon 4 genotype individuals appeared to be more vulnerable to the effects of low and high levels of leisure activities.