Mid‐life cardiorespiratory fitness and risk of late‐onset dementia incidence

INTRODUCTION Cardiorespiratory fitness (CRF) is linked to dementia risk, but moderating factors remain unclear. This study examined how and when CRF in adulthood is associated with late‐onset dementia (> 65 years) and whether sex, civil status, or education moderate this association. METHODS In a cohort of 370,980 dementia‐free individuals followed for a mean of 11.9 (standard deviation 6.0) years, CRF was estimated via a submaximal cycle test, with dementia incidence obtained from Swedish National Healthcare Registries. RESULTS Results showed that high CRF was associated with lower dementia risk in those under age 55 (hazard ratio [HR]: 0.58, 95% confidence interval [CI] 0.36–0.92) and those > 55 (HR: 0.75, 95% CI 0.63–0.89) at CRF assessment. Medium education levels moderate the association in individuals < 55 years. DISCUSSION These findings underscore the role of maintaining a high CRF in dementia prevention, emphasizing education level as a critical moderating factor. Highlights High cardiorespiratory fitness (CRF) is longitudinally associated with a lower risk of late‐onset dementia. The association was evident in those both under and over age 55 at CRF assessment. Higher education levels moderated the relationship in those < 55 years. Sex and civil status did not moderate the association.