The prevalence of depressive symptoms in Chinese longevous persons and its correlation with vitamin D status

BACKGROUND: Hypovitaminosis D and depressive syndromes are common conditions in old adults. However, little is known about the relationship between vitamin D and depression in exceptional aged people. The objective of this study is to evaluate the relationship between vitamin D levels and depressive symptoms in Chinese longevous persons. METHODS: We used a dataset from a cross-sectional survey of a sample of Chinese longevous people with self-reported age 100 or older, including 175 men and 765 women, was conducted from June 2014 to December 2016 in Hainan Province, China. Data on demographics, lifestyle characteristics and health conditions were collected using a structured questionnaire. Anthropometrics and blood samples were obtained following the standard procedure. Depressive symptoms of the participants were assessed using a shortened version of the Geriatric Depression Scale (GDS-15). Serum vitamin D levels were measured using an automated radioimmunoassay. RESULTS: The prevalence of longevous persons with depressive symptoms among the sample was 32.2% (95% confidence interval: 29.7–34.7%). Serum vitamin D levels were lower in participants with depressive symptoms than in those without (20.8 ± 8.7 vs. 23.7 ± 9.7, ng/mL). Vitamin D deficiency was an independent risk factor for depression after controlling for the potential covariates (Odds ratio = 1.47, 95% Confidence interval = 1.08–2.00; p = 0.014). A negative relationship between serum vitamin D levels and depressive symptoms was also detected, and the relationship remained significant after adjusting for a wide range of other covariates. The multivariate adjusted odds ratio of depressive symptoms for the lowest versus highest quartiles of vitamin D levels was 1.73 (95% confidence interval: 1.10–2.72), and the adjusted odds ratio with a 5 ng/mL decrement of serum 25OHD levels was 1.10 (95% confidence interval: 1.01–1.19). CONCLUSIONS: This study showed an inverse association between vitamin D levels and depressive symptoms among Chinese longevous persons. Depressive symptoms should be screened in longevous persons who had vitamin D deficiency. Further studies on vitamin D supplement and prevention along with treatment of depression are needed among very old population.