Correlation Between Vitamin D Levels And Physical Development Of Children Aged 0-6 Years In Hainan Province

Object:This study was conducted to grasp the nutritional status of vitamin D in children aged 0-6 years in Hainan Province through an epidemiological survey,to investigate the factors influencing the nutritional status of vitamin D in children aged0-6 years in Hainan Province and the relationship between it and physical development.It will provide a scientific basis for preventing vitamin D deficiency in children and improving their vitamin D nutritional status.Method:1.During the period from January 2021 to June 2022,this study took children aged 0-6 years in 18 cities and counties in Hainan Province except Sansha City as the research object.According to their geographical location,economic development level,infant mortality rate,and other causes,cities and counties are divided into two categories:urban and rural.A total of 7,174 children were included in the study as the research objects,using each health center or community health service center in the sampled township or street as the sampling point and using a continuous recruitment method for convenience sampling and subjects included in the study.2.The study was conducted by trained staff who conducted face-to-face questionnaires with parents at the sampling point and collected relevant information on children and their parents.In this study,physical measurements,including physical developmental indicators such as children’s length/height and weight,were performed on the enrolled children,and blood samples were collected in the morning to measure serum 25(OH)D levels by high-performance liquid chromatography-tandem mass spectrometry.Statistical analysis was performed on the research data to compare group differences in the serum 25(OH)D level and nutritional status of the research subjects.Logistic regression was applied to analyze the factors affecting serum vitamin D deficiency and insufficiency,and to explore the correlation between serum vitamin D levels and physical developmental indicators.Results:1.This study covered 7,174 children aged 0-6 in Hainan Province,including3,854 cases(53.7%)of boys,and the ratio of boys and girls was 1.16:1.Among the enrolled children,199 cases(2.8%)were vitamin D deficient,with a median25(OH)D level of 25.45 nmol/L;376 cases(5.2%)were vitamin D deficient,with a median of 44.84 nmol/L.After statistical analysis,the results showed that,a significant decrease in serum vitamin D levels and supplementation with vitamin D preparations in children aged 3 to 6 years.The analysis of influencing factors shows that:girls(OR=1.320,95%CI:1.093～1.595),picky eaters(OR=1.687,95%CI:1.379～2.065),other family type(OR=1.708,95%CI:1.212～2.408),exclusive breastfeeding to 6 months of age(OR=1.272,95%CI:1.013～1.597)and children over3 years old are risk factors for vitamin D deficiency and insufficiency.Rural areas(OR=0.263,95%CI:0.212～0.327),Li nationality children(OR=0.692,95%CI:0.524～0.912),the duration of outdoor activities≥2 hours(OR=0.457,95%CI:0.368～0.567),and the frequency of vitamin D supplementation and calcium supplementation were protective factors for vitamin D deficiency and insufficiency in children(P<0.05).2.The physical development status of 7,174 children aged 0-6 in Hainan Province showed that the rates of underweight,growth retardation,wasting and overweight/obesity were 4.1%,5.1%,3.9%and3.7%respectively.The results of the trend X~2test showed that the incidences of underweight,overweight/obesity,and anemia tended to increase with age.Serum vitamin D levels were used as the independent variable to analyze its correlation with physical development in children.The single factor results showed that there were statistically significant differences in serum vitamin D levels in underweight,growth retardation and overweight/obesity(P<0.05).Further regression analysis of these differential variables as dependent variables showed that serum 25(OH)D levels<50 nmol/L was correlated with growth retardation(OR=1.926,95%CI:1.276～2.907)(P<0.05).Spearman’s correlation analysis showed a statistical association between serum25(OH)D levels and HAZ,an indicator of physical development,with a positive correlation(rs=0.032,P=0.007)and a weak correlation.Conclusion:1.The overall vitamin D nutritional status of children aged 0-6 years in Hainan Province was good.Vitamin D levels and vitamin D supplementation rates of children under 3 years of age are better than those of children aged 3-6 years.2.Place of residence,Li ethnicity,length of outdoor activity,and regular supplementation of nutrient preparations were factors influencing vitamin D nutritional status.3.Vitamin D level was positively correlated with HAZ,the physical development index of children aged 0-6 years in Hainan Province,and vitamin D deficiency and insufficiency were risk factors for growth retardation in children.