Background: Recent evidence has reported the relationships between 25-hydroxyvitamin D (25[OH]D) insufficiency and chronic diseases. This study examined the association of physical activity and sitting time with vitamin D status. Methods: This study analyzed the data of 1,598 adults aged ≥19 who participated in the 2014 Korea National Health and Nutrition Examination Survey. Vitamin D insufficiency was defined as a serum 25(OH)D level of ≤20 ng/mL. The odds ratios and 95% confidence intervals of vitamin D insufficiency according to physical activity and sitting time were calculated using a multivariable logistic regression analysis. Results: The mean levels of serum 25(OH)D were 16.5 ng/mL in males and 15.2 ng/mL in females, respectively and was significantly higher in the participants with sitting times of <5 hours/day than those with sitting times of ≥5 hours/day. After adjusting for confounding variables, sitting time of <5 hours/day was associated with decreased odds of vitamin D insufficiency as compared with sitting time of ≥5 hours/day in the total participants and females. In addition, the odds ratio for vitamin D insufficiency was significantly lower in the group with sitting times of <5 hours/ day than in the group with sitting times of ≥5 hours/day even among people with low physical activity in the total participants and females. Conclusion Serum 25(OH)D level was insufficient in the Korean adults and shorter sitting time was related to lower odds ratio of vitamin D insufficiency. Our findings suggest that sitting time is an independent factor of serum vitamin D status.

Background: Recent studies have indicated that vitamin D deficiency is associated with diabetes and hypertension in adults. However, this association has not been sufficiently studied in cases of prediabetes and prehypertension. Thus, this study aimed to clarify the relationship between vitamin D levels and prediabetes and prehypertension in Korean adults. Methods: Data from 1,808 adults aged ≥19 years who participated in the 2013–2015 Korea National Health and Nutrition Examination Survey were included in this study. The odds ratio of prediabetes and prehypertension according to the 25-hydroxyvitamin D (25[OH]D) status was calculated using multivariable logistic regression analysis. Results: Mean serum 25(OH)D levels were significantly different among females with normal glucose levels, prediabetes, and diabetes mellitus. Further, the mean levels were not significantly different in both males and females of all ages with normal blood pressure, prehypertension, and hypertension. In addition, logistic regression analysis showed that serum 25(OH)D levels were not significantly associated with the odds ratio of prediabetes and prehypertension after adjusting for age, sex, smoking, alcohol consumption, physical activity, calcium supplement intake, income, body mass index, systolic blood pressure, and fasting glucose. Conclusion Serum vitamin D status was not independently associated with the risks of prediabetes and prehypertension in Korean adults.