Objective Vitamin D deficiency is now recognised as a common health problem associated with various chronic diseases; however, it has not been fully elucidated among the minority groups. Here, we aimed to investigate the prevalence of vitamin D deficiency and its associated metabolic risk factors among North Korean refugees living in South Korea.

Design Cross-sectional analysis from the longitudinal cohort, the North Korean refugee health in South Korea (NORNS) study.

Participants A total of 386 North Korean refugees aged ≥30 years, who measured serum 25-hydroxy vitamin D (25(OH)D) level.

Results The prevalence of vitamin D deficiency (25(OH)D <20 ng/mL) was 87% and no participants had an adequate vitamin D level (25(OH)D ≥30 ng/mL). Underweight participants (body mass index (BMI) <18 kg/m²) had significantly lower 25(OH)D levels than individuals with normal BMI (≥18.5 and<23 kg/m²). In the multivariate logistic regression analysis, the lowest 25(OH)D level (<10 ng/mL) was significantly associated with metabolic syndrome (OR, 6.37, 95% CI 1.34 to 30.3), high triglyceride (OR, 6.71, 95% CI 1.75 to 25.7), and low high-density lipoprotein (OR, 5.98, 95% CI 1.54 to 23.2) compared with 25(OH)D levels ≥20 ng/mL after adjusting for age, sex, season, length of residence in South Korea, physical activity and BMI.

Conclusions Vitamin D deficiency is very common among North Korean refugees in South Korea. Despite their lower BMI, vitamin D deficiency was associated with metabolic syndrome in this population.