Background: Few studies evaluated the association between vitamin D and psychological health in Chinese. This study examined these associations in Chinese older men in Hong Kong.
Methods: Baseline serum 25-hydroxyvitamin D (25OHD), depression and cognitive function were assessed in 939 community-dwelling Chinese men aged >65. Data on depression status at 4-year follow up was available in 629 men. Data were collected for confounding factors: demographics, number of diseases, smoking, alcohol use, body mass index, physical activity, mobility limitations, dietary intake, season of blood measurement, and serum parathyroid hormone level. Multivariate logistic regression analyses were performed with adjustments for confounding factors.
Results: An inverse association between serum 25OHD and baseline depression was observed. Men in the highest (>=92 nmol/L) compared with lowest (<=63 nmol/L) quartile of serum 25OHD had an adjusted odds ratio for depression of 0.46 (95% CI: 0.22-0.98, P(trend)=0.004). The association was more pronounced in low vitamin D season than in high vitamin D season. No association was observed between serum 25OHD and incident depression at 4 years. Baseline cognitive impairment was not associated with serum 25OHD in all models.
Limitations: Self-reported measure of depression and cognitive performance, the small number of incident depression at 4-year follow up and selection bias may affect the study validity.
Conclusions: Serum 25OHD was inversely associated with depression at baseline and was not linked to baseline cognitive impairment and 4-year incident depression in Chinese older men. Future studies are warranted to evaluate these associations in populations with higher prevalence of vitamin D deficiency.
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