Vitamin D deficiency and associated factors in south Korean childbearing women: a cross-sectional study.

This study showed a high prevalence of vitamin D deficiency in Korean female nurses. Serum levels of vitamin D were associated with age and season. Vitamin D deficiency should be recognized as one of the primary health concerns among young women. More proactive actions, such as vitamin D supplements and food fortification, are needed to improve vitamin D deficiency in high-risk groups.