Background: The relationship between serum vitamin D levels and depressive symptoms has not been consistent in previous studies in Korean women. Menopause is known to be related to depression and vitamin D.Methods: This study included 11,573 women from the 5th Korea National Health and Nutrition Examination Survey. Serum vitamin D levels were divided into four groups according to quartiles, and depressive symptoms were collected into two groups. Multiple logistic regression analysis was conducted in each group of women before and after menopause.Results: Compared with the highest vitamin D group, the lowest vitamin D group did not show significant differences in all females (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.78-1.22). In premenopausal women, compared to the first quartile, ORs were presented in the second quartile (OR, 0.75; 95% CI, 0.53-1.07), third quartile (OR, 0.70; 95% CI, 0.49-1.00) and fourth quartile (OR, 0.62; 95% CI, 0.43-0.92) respectively, and they were statistically significant (<i>P</i>=0.016). In postmenopausal women, compared to the first quartile, ORs were presented in the second quartile (OR, 1.06; 95% CI, 0.78-1.44), third quartile (OR, 1.18; 95% CI, 0.87-1.61), and fourth quartile (OR, 1.27; 95% CI, 0.98-1.66) respectively; however, they were not statistically significant (<i>P</i>=0.057).Conclusions: Depression symptoms increased with a decrease in serum vitamin D in premenopausal women, but the opposite trend was observed in postmenopausal women. In future studies, if the relationship between blood vitamin D and depression is studied, the menopausal status of women can be used as an important criterion.

Background: Sleep duration is associated with various health conditions, including chronic kidney disease. However, the association between sleep duration and decline in kidney function in the South Korean population remains unclear. We aimed to investigate the impact of sleep duration on kidney function decline in adult patients with hypertension.Methods: This cohort study was performed using data obtained from the Korean Genome and Epidemiology Study; 2,837 patients with hypertension who initially had normal kidney function were included. Glomerular filtration rates (GFRs) were estimated at baseline and throughout the 16 years of follow-up. A person was considered to have a decline in kidney function if they had a GFR <60 mL/min/1.73 m². Sleep duration data were obtained through interviewer-assisted questionnaires. Sleep durations were classified as short (<6 hours), normal (≥6 hours but <9 hours), and long (≥9 hours). The Cox proportional hazards model was applied, with adjustments for covariates.Results: After adjusting for covariates, sleep duration was not associated with a decline in kidney function. However, among men with poorly controlled hypertension at baseline, compared to men with normal sleep durations, men with sleep durations <6 hours had a significantly higher risk of kidney function decline (hazard ratio, 1.56; 95% confidence interval, 1.02–2.36).Conclusion: Short sleep duration did not seem to be associated with an increased risk of decline in kidney function; however, it may be a risk factor for the decline in kidney function in men with poorly controlled hypertension.