[Vitamin D status and relevant factors of children and adolescent aged 6-17 in Yunnan Province from 2016 to 2017].

Abstract

Objective: To analyze the prevalence status and related factors of Vitamin D in children and adolescent aged 6-17 years in Yunnan Province, and to provide evidence for improving the anemia status of children and teenagers in Yunnan Province.

Methods: From 2016 to 2017, a multi-stage stratified random sampling method was used to select 3189 children and adolescents aged 6-17 from 65 primary and secondary schools in 13 counties(cities, districts) of 7 cities(prefectures) in Yunnan Province.1580 boys and 1609 girls were selected by gender.1367 urban residents and 1822 rural residents were selected for face-to-face questionnaire survey and serum vitamin D measurement based on urban and rural areas. The distribution of serum vitamin D content in urban and rural areas, age, body mass index and outdoor activity time of school-aged children was analyzed. SPSS20.0 T-test, χ~2 test and multiple Logistic regression analysis were performed.

Results: The mean of vitamin D in children and adolescents aged 6-17 in Yunnan Province was(21.98±8.07) ng/mL. The vitamin D level of urban boys was(23.30±10.13) ng/mL, which was higher than that of girls((21.50±8.94) ng/mL)(t=3.47, P<0.01). The vitamin D level of children and adolescents aged 6-8 in urban areas was the highest((26.65±9.83) ng/mL), and the difference was statistically significant compared with other age groups except for the 15-17 age group(F=41.06, P<0.01). The vitamin D levels of children and adolescents who had physical examinations in autumn, ate eggs every day, and had eaten animal blood and liver in the past month were(25.34±7.82), (22.78±9.60) and(23.66±9.24) ng/mL, respectively, which were all higher than those of other groups, and the differences were statistically significant(P<0.05). The vitamin D level of rural boys was(22.85±7.31) ng/mL, which was higher than that of girls((20.10±6.34) ng/mL)(t=5.34, P<0.01). The vitamin D level of children and adolescents aged 6-8 in rural areas was the highest((23.7±7.96) ng/mL), and the difference was statistically significant compared with other age groups except for the 15-17 age group(F=25.05, P<0.01), but it was lower than that of the same age group in urban areas(t=4.40, P<0.01). The vitamin D level was the highest when outdoor activity time exceeded 120 minutes((22.05±7.84) ng/mL), and the difference was statistically significant compared with other activity time groups(F=5.34, P<0.01). The rate of vitamin D insufficiency and deficiency among children and adolescents aged 6-17 was 87.6%. The proportion of vitamin D insufficiency or deficiency among girls in both urban and rural areas was higher than that among boys(χ~2 values of 17.48 and 35.33, P<0.01), respectively. The proportion of vitamin D insufficiency or deficiency among different genders in urban and rural areas was statistically significant(χ~2=50.14, P<0.01). In urban and rural age groups, the proportion of vitamin D sufficiency in 6-8 years old was the highest, accounting for 40.6% and 38.5%, respectively, and the difference between urban and rural vitamin D deficiency or deficiency was statistically significant(χ~2=71.22 P<0.01). Vitamin D insufficiency and deficiency were more severe in winter among children and adolescents in both urban and rural areas(χ~2=17.11, P<0.01. Multivariate Logistic analysis showed that girls(OR=2.27, 95%CI 1.814-2.852) and rural children and adolescents(OR=1.560, 95%CI 1.240-1.961) were more likely to have vitamin D insufficiency or deficiency. The 6-8 age group(OR=0.395, 95%CI 0.287-0.543), physical examination season in spring(OR=0.694, 95%CI 0.567-0.849), and autumn(OR=0.743, 95%CI 0.595-0.926) were protective factors for vitamin D insufficiency or deficiency.

Conclusion: The deficiency or insufficiency of vitamin D among children and adolescents aged 6 to 17 in Yunnan Province from 2016 to 2017 remains at a relatively high level, with girls being more prominently affected. Undergoing physical examinations in spring and autumn is a protective factor for vitamin D levels.