Abstract
Background: High blood pressure and poor cardiorespiratory fitness are independent risk factors for dementia. However, few studies have examined if combined longitudinal patterns of these modifiable risk factors are associated with dementia risk.
Methods: In this prospective cohort study, we used data from the population-based HUNT Study, Norway. We applied group-based multidimensional trajectory modeling to identify age-specific multidimensional trajectories of SBP, DBP and estimated cardiorespiratory fitness across three surveys (HUNT1, 1984-86 – HUNT3, 2006-08). Dementia was diagnosed in the HUNT4 70+ substudy in 2017-19. We used multivariate logistic regression to estimate odds ratios (ORs) and risk differences (RDs) of dementia.
Results: In total, 7594 participants (54.9% women) were included, with a mean age of 44.7 (SD 6.3) years at HUNT1. Dementia was diagnosed in 1062 (14.0%) participants. We identified two multidimensional trajectories throughout adulthood within three age groups: one with higher SBP and DBP, and lower estimated cardiorespiratory fitness (the poorer group), and one with lower SBP and DBP, and higher cardiorespiratory fitness (the better group). After adjustment for sex, APOE ε4 status, education, marital status and diabetes, the better group had consistently lower risk of dementia in all age groups with the lowest OR in the middle-aged group of 0.63 (95% CI 0.51, 0.78) with corresponding RD of -0.07 (95% CI -0.10, -0.04).
Conclusions: Having a beneficial multidimensional trajectory of SBP, DBP and cardiorespiratory fitness in adulthood was associated with reduced dementia risk. Aiming for optimal SBP, DBP and estimated cardiorespiratory fitness throughout adulthood may reduce dementia risk.