Introduction: We investigated whether the protective association of physical activity with risk of Alzheimer's disease and related dementias (ADRD) has genetic or behavioral variations.
Methods: In the Multiethnic Cohort, we analyzed moderate or vigorous physical activity (MVPA) reported at ages 45 to 75 among 88,047 participants in relation to 13,039 incident diagnoses of late-onset ADRD identified in Medicare claims (1999 to 2014), by five racial and ethnic groups, hours sitting, and in a subset (16%), apolipoprotein E (APOE) genotype.
Results: MVPA was inversely associated with ADRD (hazard ratio for ≥14 vs <2.5 hours/week: 0.83, 95% confidence interval [CI]: 0.76 to 0.90 in men; 0.88, 5% CI: 0.81 to 0.95 in women). The association was inverse in all racial and ethnic groups except Black participants (P-heterogeneity = 0.52), but stronger in individuals with lower levels of sitting duration or those who do not carry the APOE e4 risk allele.
Discussion: The different effects of physical activity by sitting duration and APOE genotype warrant further research.
Keywords: Alzheimer's disease; dementia; physical activity; prospective studies; race and ethnicity; sitting.
© 2022 the Alzheimer's Association.