Vitamin D status among residents of Molidawa Daur Autonomous Banner, Inner Mongolia, North China.

OBJECTIVES: To retrospectively analyze the vitamin D (VD) status of residents in northeastern Inner Mongolia and its relationship with the average monthly sunshine hours.

METHODS: Serum 25-hydroxyvitamin D[s-25(OH)D] samples from 4982 outpatients (2092 males) in Moli Dawa Daur Autonomous Banner People's Hospital, Hulunbuir, China from July 2018 to January 2022 were included in this study.

RESULTS: The overall median s-25(OH)D was 53.3 nmol/L, VD deficiency (<30 nmol/L), deficiency (30-50 nmol/L), sufficient (>50-250 nmol/L) and excess (>250 nmol/L) were 16% (796/4982), 30% (1495/4982), 53.4% (2658/4982) and 0.7% (33/4982). There were statistically significant differences in median s-25(OH)D by month, age-groups and gender ( p <0.001). Low VD status (LVDS, including VD deficiency and insufficiency) in females was 54.6% and males was 33.9%, and the LVDS composition differed significantly by age-group and month ( p <0.05). The changing trend of the median s-25(OH)D level was similar to the monthly average sunshine hours, with a slight lag.

CONCLUSION: Nearly half of residents live in LVDS. LVDS is affected by month, gender, and age.