Associations of serum 25(OH)D levels with depression and depressed condition in Korean adults: results from KNHANES 2008-2010 / 한국영양학회지

PURPOSE: Vitamin D has been known to play an important role in the central nervous system and brain functions in the human body, and cumulative evidence has shown that vitamin D deficiency might be linked with various mental health conditions. Epidemiologic studies have shown that vitamin D deficiency may be associated with higher risk of depression in the US and European populations. However, limited information is available regarding the association between vitamin D status and depression in the Korean population. The objective of this study was to examine the associations between vitamin D levels and prevalence of depression. METHODS: We conducted a cross-sectional analysis using nationally representative data from the 2008-2010 Korean National Health and Nutrition Examination Survey from which serum 25-hydroxyvitamin D concentrations were available. A total of 18,735 adults who had available demographic, dietary, and lifestyle information were included in our analysis. We defined "depression" with a diagnosis by a physician. "Depressed condition" was defined as having feelings of sadness or depression without diagnosis by a physician. RESULTS: The prevalence of depression was 1.63% and 5.43% in Korean men and women, respectively; 12.5% of men and 26.1% of women were defined as the group having depressed conditions. In multivariate logistic regression models, no significant associations were observed between vitamin D status and prevalence of depression or depressed conditions in Korean men and women. CONCLUSION: We found no association between vitamin D insufficiency and depression/depressed conditions in Korean adults. Future large prospective studies and randomized controlled trials are needed to confirm this relationship.

Nutrient Intake, Lifestyle Factors and Prevalent Hypertension in Korean Adults: Results from 2007-2008 Korean National Health and Nutrition Examination Survey / 대한지역사회영양학회지

Hypertension is a well-known risk factor for cardiovascular disease. Previous studies have shown that changes in diet and lifestyle factors can prevent the development of hypertension, but the combined effects of these modifiable factors on hypertension are not well established. The objective of this study is to investigate associations of diet and lifestyle factors, evaluated both individually and in combination, with prevalent hypertension among Korean adults. We analyzed data obtained from the 2007-2008 Korean National Health and Nutritional Examination Survey, a nationwide cross-sectional study using a stratified, multistage probability sampling design. The associations of 12 nutrient intakes and lifestyle factors with risk of hypertension were explored using restricted cubic spline regression and logistic regression models among 6,351 adults. Total energy and several nutrients and minerals, including, calcium, vitamin A, vitamin C, and sodium, showed non-linear relationships with the risk of prevalent hypertension. In multivariate logistic regression models, dietary score, obesity and alcohol intake were independently associated with the risk of prevalent hypertension, but smoking and physical activity were not. Overall, participants whose dietary habits and lifestyle factors were all in the low-risk group had 68% lower prevalence of hypertension (OR: 0.32, 95 CI: 0.14-0.74) compared to those who were at least one in the high-risk group of any dietary or lifestyle factors. The result suggests that combined optimal lifestyle habits are strongly associated with lower prevalence of hypertension among Korean adults.

The Association between Consumption of Processed Meat and Prevalence of Metabolic Syndrome Among Korean Adults: Based on 2007-2008 Korean National Health and Nutrition Examination Survey

Recent studies have shown that high consumption of processed meat may be associated with increasing risk of metabolic syndrome, which have been suggested as a predictor of diabetes and cardiovascular disease. However, limited studies have investigated this association in Korean population. The purpose of this study was to investigate the cross-sectional association between processed meat/unprocessed (beef, pork, chicken) intakes and the prevalence of metabolic syndrome. Using data from 2007-2008 Korean National Health and Nutrition Examination Survey (KNHANES), we analyzed data including 5,545 men and women who were aged older than 20 years, and who were free of chronic disease such as hypertension, type 2 diabetes and cardiovascular disease. Subjects who frequently consumed processed meat tended to be younger and more likely to be current smokers. In addition, men were more likely to consume processed meat than women. Although higher processed/unprocessed meat intakes were significantly associated with the lower risk of metabolic syndrome in a crude model, these associations were no longer significant after adjustment for potential confounding factors. For example, comparing subjects in the highest intake quartile of processed meat with the lowest intake group, the multivariate-adjusted odds ratio (OR) of metabolic syndrome was 0.92 (95% CI: 0.58-1.46) for processed meat, 1.09 (95% CI: 0.76-1.56) for beef, 1.10 (95% CI: 0.74-1.62) for pork and 0.75 (95% CI: 0.51-1.12) for chicken. In conclusion, we found no evidence of any adverse effects of frequent processed or unprocessed meat intakes on the prevalence of metabolic syndrome among Korean adults at the exposure levels seen in this study.