Healthy lifestyles, survival, and dementia risk: a prospective cohort study

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Background A healthier lifestyle is promoted as a strategy to prevent or delay dementia; however, it remains unclear whether this translates into real-world decreases in dementia burden at the population level. This prospective cohort study examined whether a healthier lifestyle, using the (items of) the LIfestyle for BRAin Health 2 (LIBRA2) index, is associated with dementia incidence and all-cause mortality. In addition, we estimated the number of dementia cases associated with different lifestyle profiles at the population level. Methods Data from the Lifelines cohort were linked to dementia healthcare claims from Vektis and mortality records from Statistics Netherlands. Discrete-time models, adjusted for age, sex, and education, were used to estimate relative risk ratios (RRR) for dementia and mortality (multinomial model) and hazard ratios (HR) for dementia. Results Among 13,811 individuals aged ≥60 years, each one-point increase in the LIBRA2 score (indicating unhealthier lifestyle) was associated with higher risk of dementia (RRR 1.05 [95% CI 1.04–1.06]) and mortality (RRR 1.16 [95% CI 1.14–1.18]). When investigating separate LIBRA2 factors, only diabetes and depression were associated with dementia risk (HR 1.39 [95% CI 1.12–1.72] and HR 1.80 [95% CI 1.26–2.57]). A double-decrement life-table simulation (10,000 individuals, until age 90) showed that 15% of individuals with the healthiest lifestyle remained alive without dementia, and 16% developed dementia. Among those with the unhealthiest lifestyle, 4% remained alive without dementia, and 13% developed dementia. Conclusions While healthier lifestyles are associated with lower dementia risk, they may increase the population-level burden as improved survival leads to more individuals reaching ages at highest risk. Prevention strategies should therefore not only reduce individual risk but also account for longer survival and its impact at older ages. Key messages • Only diabetes and depression raised dementia risk overall; other risks varied by age, sex, and education. Composite scores may hide differences and reduce prediction accuracy. • LIBRA2 shows healthier lifestyles lower dementia and mortality, implying demographic shifts in ageing populations. This creates a trade-off for healthcare planning and resource allocation.