Abstract
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.