[Association Between Blood Selenium Level and Depressive Symptoms in Older Adults Aged 65 Years and above in 18 Longevity Areas in China].

Objective: To investigate the association between blood selenium (Se) level and depressive symptoms among the older adults aged ≥65 years in 18 longevity regions of China. Methods: Based on the 2021 China Healthy Ageing and Biomarkers Cohort Study, 5 278 participants were enrolled. In this study, inductively coupled plasma-mass spectrometry was used to measure blood Se levels, and the Patient Health Questionnaire-9 was used to assess depressive symptoms; a score of ≥10 was defined as indicative of depressive symptoms. Multivariable logistic regression models and restricted cubic spline (RCS) analyses were utilized to examine the association and dose-response relationship between blood Se levels and depressive symptoms. Results: The mean age of participants was (84.15±11.28) years old, and 55.2% were female. A total of 332 older adults with depressive symptoms were detected, with a detection rate of 6.3%. Compared with those without depressive symptoms, older adults with depressive symptoms have lower blood Se levels (P<0.001), which are (105.02±29.77) μg/L and (112.53±31.84) μg/L, respectively. Multivariate logistic regression results showed a negative association between blood Se levels and the risk of depressive symptoms. After adjusting for all covariates, for every 10 μg/L increase in blood Se levels, the risk of depressive symptoms decreased by 5% (OR=0.95, 95%CI: 0.91-0.99). Compared with the Q1, the ORs (95%CIs) of blood Se in Q2, Q3, and Q4 were 0.85 (0.63-1.15), 0.69 (0.49-0.95), and 0.67 (0.47-0.94), respectively. Furthermore, RCS analysis revealed a near-linear negative dose-response relationship between blood Se levels and the risk of depressive symptoms (P for linear =0.055). Conclusion: Blood Se level is significantly associated with decreased risk of depressive symptoms among older adults aged 65 and older in 18 longevity regions of China.