Upward changes in serum 25-hydroxyvitamin D levels in South Korea: the Korea National Health and Nutrition Examination Survey studies IX (2022–2023) versus VI (2013–2014)
Serum 25(OH)D levels significantly increased across both sexes and all age groups and the odds of vitamin D deficiency were significantly lower in KNHANES IX compared to VI, with adjusted odds ratios of 0.358 for men and 0.214 for women.