Vitamin D status in children and its association with glucose metabolism in northern China: a combination of a cross-sectional and retrospective study

OBJECTIVES: This study aimed to explore the vitamin D status of children in northern China and the association between vitamin D and glucose metabolism. DESIGN: Cross-sectional study was conducted among child participants and retrospective study designs were conducted among adult participants. SETTING AND PARTICIPANTS: Both studies were recruited from Harbin, 326 children were included in children’s study, 8469 adults were included in adult study. PRIMARY AND SECONDARY OUTCOME MEASURES: Physical examination, lifestyle and dietary habit data were recorded in all the participants. Serum insulin, glucose, 25(OH)D(3) concentrations in children and serum glucose and lipids levels in adults were measured. Rickets history was also investigated in adults, which was used to define vitamin D deficiency in childhood. The associations were tested by linear regression and binary logistic regression. RESULT: In the children’s study, only 10.7% of participants were vitamin D sufficient (≥30 ng/mL). Inverse correlations between serum 25(OH)D(3) concentration and fasting insulin and homeostasis model assessment - insulin resistance (HOMA-IR) were found, and children with lower serum 25(OH)D(3) concentrations were likely to have insulin resistance (IR) (OR: 0.955, 95% CI: 0.917 to 0.995, p value: 0.027). In an adult study, rickets in childhood increased the risk of type 2 diabetes in male participants (OR=1.414, 95% CI=1.013 to 1.972; p value=0.042), but this result was not observed in female participants. CONCLUSION: Our findings suggest that vitamin D deficiency is widespread in northern China. Vitamin D deficiency in childhood was associated with IR and increased the risk of type 2 diabetes in male adults.