Associations of healthy lifestyle with depression and post-depression dementia: A prospective cohort study

Depressive symptoms may be a risk factor or prodrome of dementia, but the modifiable risk factors for dementia after onset of depression has not been fully elucidated. The current study aimed to investigate the associations of lifestyle factors with depression and post-depression dementia. Our analysis was based on data from the ongoing UK Biobank study, which included 497,533 participants (age 37–73 years) between 2006 and 2010, and thereafter followed up to 2020. High-risk lifestyle factors included current smoking, heavy alcohol intaking, poor diet pattern, physically inactive. Multistate models were used to estimate the transition-specific hazard ratios (HRs) and 95 % confidence intervals (CIs). During a 14.8-year follow-up, 23,164 participants developed depression, and 989 developed post-depression dementia. The incidence rate of dementia in people with depression was far more than those who were free of depression. In multistate model, high-risk lifestyle factors were substantially associated with higher risks of incident depression (HR = 2.14, 95 % CI: 1.95–2.35), dementia (HR = 1.87, 95 % CI: 1.51–2.31), and post-depression dementia (HR = 1.72, 95 % CI: 1.13–2.62). When the analyses were divided by individual lifestyle factors, we found that only physically inactive contributed significantly to the development of dementia after the onset of depression (HR = 1.15, 95 % CI: 1.01–1.30). Our study found that high-risk lifestyle factors were associated with higher risk of transition from depression to dementia, highlighting the great significance of integrating comprehensive behavioral interventions, particularly for regular physical activity, for prevention of both depression and post-depression dementia. •The incidence rate of dementia in people with depression was far more than those free of depression•High-risk lifestyle factors were associated with higher risk of depression and post-depression dementia•Physically inactive was associated with higher risk of comorbid dementia after the onset of depression