The long-term relation between physical activity and executive function in the Rotterdam Study

Background Research on the association between physical inactivity and cognitive decline and dementia is dominated by studies with short-term follow-up, that might be biased by reverse causality.
Objective Investigate the long-term association between physical activity, cognition, and the rate of age-associated cognitive decline.
Methods We investigated the association between late-life physical activity and executive functioning and rate of decline of executive abilities during follow-up of up to 16 years, in 3553 participants of the prospective Rotterdam Study cohort. Measurement took place in 1997–1999, 2002–2004, 2009–2011, and 2014–2015.
Results At baseline (age ± 72 years), higher levels of physical activity were associated with higher levels of executive functioning (adjusted mean difference = 0.03, 95% CI: 0.00 ; 0.06, p = 0.03). This difference remained intact up to 16 years of follow-up. The level of physical activity at baseline was unrelated to the rate of decline of executive abilities over time, in the whole group (adjusted mean difference in changetime*physical activity = 0.00, 95% CI: -0.00 ; 0.01, p = 0.31). However, stratification by APOE genotype showed that the accelerated decline of executive abilities observed in those with the ApoE-ε4 allele might be attenuated by higher levels of physical activity in late adulthood (ApoE-ε4 carriers: Btime*physical activity = 0.01, 95% CI: 0.00 ; 0.01, p = 0.03).
Conclusion Higher levels of physical activity in late adulthood are related to higher levels of executive functioning, up to 16 years of follow-up. Accelerated decline of executive abilities observed in those with the ApoE-ε4 allele might be mitigated by higher levels of physical activity.