[Study on the association between vitamin D and body fat distribution in children and adolescents]

Objective: To investigate the association of vitamin D with distribution of body fat in children and adolescents. Methods: Data were obtained from the baseline survey of School-based Cardiovascular and Bone Health Promotion Program in 2017. Multiple linear regression and multinomial logistic regression models were applied to analyze the relationships of body mass index (BMI), fat mass index (FMI), trunk fat mass index (TFMI), appendicular fat mass index (AFMI), and visceral fat area(VFA) with vitamin D level and status in children and adolescents. Results: A total of 11 960 children and adolescents were included in the analysis (boys accounting for 49.7%). The average age and serum vitamin D level of study population were (11.0±3.3) years and (35.0±11.9) nmol/L, respectively. The deficiency rate of vitamin D was 37.2%. Gender-specific associations of BMI, FMI, TFMI, and AFMI with vitamin D level were found (P for interaction <0.05): they were inversely associated with vitamin D level in boys (BMI: β=-0.56; FMI: β =-0.59; TFMI: β=-0.60; AFMI: β=-0.59; all P<0.05), but not in girls (P>0.05). VFA was positively associated with vitamin D deficiency and insufficiency in both boys and girls, and the risks of vitamin D deficiency and insufficiency all increased by 17%(95%CI: 9%-25%) for per increment of standard deviation in VFA. Conclusions: The higher level of visceral fat was associated with the lower vitamin D levels in children. Abdominal obese children and boys with excessive body fat are the key population in the prevention and control of vitamin D deficiency.