Meta-analysis Of Vitamin D Nutritional Status Of Children In 20 Cities Of 11 Provinces

Background:In recent years,the global vitamin D nutritional status has attracted much attention.There may be different in vitamin D nutritional status in different countries and regions.There are few relevant studies on the multi-center large sample size of children’s vitamin D nutritional status in China.Objective To analyze the nutritional status of children’s vitamin D levels in China’s mainland.Methods: Search Pub Med,Embase,The Cochrane Library,Wanfang Data Knowledge Service Platform,China Knowledge Network,China Biomedical Literature Database,Weipu Chinese Journal Database and other databases.Retrieval time is from the establishment of the database to April 8,2020.Two researchers independently extracted sex,age,season,serum25-hydroxyvitamin D(25(OH)D)level,and serum 25(OH)D level of children and adolescents of different genders(<20ng / ml,20～30ng /ml,30～150ng / ml)incidence rate and other data and evaluate the risk of literature bias.Meta-analysis was carried out using Rev Man5.2 and Stata14.0 software.Results: A total of 29 studies and 133,441 healthy children and adolescents were enrolled in this paper.The overall serum of 25(OH)D level was 29.62± 12.45 ng / ml.We set a serum of 25(OH)D level of20ng/ml as a deficient cut-off value.The meta analysis results showed that the overall vitamin D deficiency rate was 21.4% [95%CI(17.5%～25.4%)].Among them,19 studies including 115,760 children in the southern region had a serum 25(OH)D level of 29.86 ± 12.11 ng / ml and a deficiency rate of 17.5% [95%CI(13.1%～22%)].There were other10 studies including 17,681 children in the northern region with a serum25(OH)D level of 28.88±12.86 ng / ml and a deficiency rate of 29.0%[95%CI(19.4% ～ 38.6%)].Among them,25 studies including 95,004 children and adolescents with serum vitamin D showed a deficiency rate of 21.19%,an insufficient rate of 38.43%,and an adequacy rate of 38.49%.There were 25 studies reported a total of 122,330 cases of serum 25(OH)D levels of children of different genders,including 70,737 boys and51,593 girls.Meta-analysis results showed that the incidence of serum25(OH)D levels in the male group was 20-30 ng / ml Higher than the female group,the difference was statistically significant [OR = 1.25,95% CI(1.01,1.54),P = 0.04].Comparison of serum 25(OH)D level between the two groups [SMD = 0.00,95% CI(-0.03,-0.03),P = 0.94],serum 25(OH)D level was <20ng / ml [OR = 1.01,95 % CI(0.97,1.06),P = 0.50],30 ～ 150 ng / ml [OR = 1.00,95% CI(0.92,1.08),P = 0.93],the difference was not statistically significant.There were 16 studies reported 75137 cases of serum 25(OH)D levels in different seasons.Meta-analysis results showed that the serum 25(OH)D levels of children in the summer group were higher than those in the spring group [SMD =-0.60,95% CI(-0.85,-0.35),P <0.00001],winter group [SMD = 0.56,95% CI(0.34,0.77),P <0.0001],the serum 25(OH)D level of children in autumn group is higher than that in spring group [SMD =-0.50,95 %CI(-0.72,0.27),P <0.0001],winter group [SMD = 0.48,95% CI(0.29,0.67),P <0.00001],the difference was statistically significant;and the children’s serum between the summer and autumn groups was 25(OH)D level comparison [SMD = 0.07,95% CI(-0.03,0.18),P = 0.18],comparison between spring and winter [SMD =-0.00,95% CI(-0.17,0.16),P = 0.99 ],The differences are not statistically significant.There were 24 studies reported a total of 127,859 serum 25(OH)D levels in different age groups,of which the infant 25(OH)D level was higher than the infant group [SMD = 0.16,95% CI(0.06,0.27),P = 0.002],Preschool group [SMD = 0.77,95% CI(0.55,1.0),P <0.00001],school-age children and adolescents group [SMD = 0.68,95% CI(0.33,1.03),P<0.0001],infant group serum 25(OH)D levels were higher than preschool group [SMD = 0.61,95% CI(0.43,0.80),P <0.00001],school-age children and adolescents group [SMD = 0.65,95% CI(0.27,1.04),P = 0.001,The preschool group is higher than the school-age children and adolescents group [SMD = 0.33,95% CI(0.15,0.51),P = 0.0004],the differences are statistically significant.Conclusion: Vitamin D deficiency in Chinese children is still severe.The vitamin D deficiency rate of children in the south is lower than that in the north.There is no significant difference in vitamin D levels between children of different genders in China’s mainland.Vitamin D levels in the summer and autumn are significantly higher than those in winter and spring.There is no significant difference in vitamin D levels between summer and autumn and between spring and winter.It decreases with age.