Long-term trajectories of basal metabolic rate and risk of depressive symptoms: evidence from three large population-based cohorts.

BACKGROUND: Depressive symptoms are a significant health concern among middle-aged and older adults. While previous studies have linked lower basal metabolic rate (BMR) to higher depression risk, the impact of BMR trajectories over time on the development of depressive symptoms remains unclear.

METHODS: Data from three large, nationally representative cohorts were analyzed: China Health and Retirement Longitudinal Study (CHARLS; n = 3117), Health and Retirement Study (HRS; n = 7284), and Survey of Health, Ageing and Retirement in Europe (SHARE; n = 5353). Group-based trajectory modeling identified BMR trajectories, and logistic regression assessed the association between these trajectories and the onset of depressive symptoms. A random-effects model was used to pool results across cohorts.

RESULTS: Three distinct BMR trajectories (low-level, medium-level, high-level) were identified, all showing a consistent decline over time. In CHARLS and HRS, higher BMR trajectories were linked to lower odds of depressive symptoms, while in SHARE, only the high-level trajectory was protective. In the fully adjusted pooled analysis (Model 3), the medium-level (OR = 0.79, 95% CI: 0.71-0.86) and high-level (OR = 0.68, 95% CI: 0.58-0.79) groups had significantly lower odds of depression compared to the low-level group. Older males with low BMR had the highest risk of depressive symptoms (pooled OR = 3.52, 95% CI: 2.17-5.71).

CONCLUSION: Among middle-aged and older adults, higher BMR trajectories are consistently associated with a lower risk of incident depressive symptoms. Older males in the low BMR trajectory identified as the highest-risk subgroup.