Objective: To explore current vitamin D status and influential factors of vitamin D deficiency and insufficiency among children under 7 years of age in 11 provinces, autonomous regions or municipalities of China. Methods: According to the "province-city-hospital" sampling technical route, a total of 1 531 healthy children under 7 years of age were sampled from 11 provinces, autonomous regions or municipalities in China by the cluster random sampling method from November 2020 to November 2021. The demographic information, family conditions, behavior and living habits and feeding behaviors were collected using unified questionnaire. Serum 25-hydroxyvitamin D(25(OH)D) levels were measured by liquid chromatography-tandem mass spectrometry. Serum 25(OH)D<30 nmol/L was considered deficient and 30-50 nmol/L was considered insufficient. With 25(OH)D≤50 nmol/L as the dependent variable, multivariate Logistic regression was applied to analyze the association between vitamin D deficiency and insufficiency and potential influential factors. Results: The prevalence of vitamin D deficiency and insufficiency among children under 7 years of age in 11 provinces, autonomous regions or municipalities of China was 14.0% (215/1 531), 3.8% (25/664) and 21.9% (190/867) in 0-<3 and 3-<7 of age years, respectively. Compared to children aged 0-<3 years, children aged 3-<7 years had a 2.6-fold increased risk of vitamin D deficiency and insufficiency (OR=3.60, 95%CI 1.93-6.72, P<0.001). Frequent sunlight exposure (OR=0.46, 95%CI 0.29-0.73, P=0.001), vitamin D supplementation (sometimes, OR=0.33, 95%CI 0.21-0.51, P<0.001; daily, OR=0.20, 95%CI 0.11-0.36, P<0.001) and infant formula intake(4-7 times per weeks, OR=0.43, 95%CI 0.28-0.68, P<0.001) were protective factors for vitamin D deficiency and insufficiency. Conclusion: Vitamin D deficiency and insufficiency are common among children under 7 years of age in 11 provinces, autonomous regions or municipalities of China, which is affected by age, sunlight exposure, vitamin D supplementation and infant formula intake.
目的： 调查我国11省、自治区、直辖市7岁以下儿童维生素D营养现状，并探讨维生素D缺乏和不足的相关影响因素。 方法： 按照“省-市-医院”的技术抽样路线，于2020年11月至2021年11月采用整群抽样的方法，抽取来自11个省、自治区、直辖市的1 531名7岁以下健康儿童为研究对象。通过统一制定的调查问卷收集儿童基本信息、家庭情况、行为生活习惯及饮食喂养等信息。应用液相色谱-串联质谱法检测儿童血清维生素D水平，血清25（OH）D<30 nmol/L为缺乏，30~50 nmol/L为不足。以25（OH）D≤50 nmol/L为因变量，采用多因素Logistic回归分析维生素D缺乏和不足的影响因素。 结果： 我国11省、自治区、直辖市7岁以下儿童维生素D缺乏和不足检出率为14.0%（215/1 531），其中0~<3岁和3~<7岁分别为3.8%（25/664）和21.9%（190/867）。与0~<3岁相比，3~<7岁儿童发生维生素D缺乏和不足的风险增加2.60倍（OR=3.60，95%CI 1.93~6.72，P<0.001）。皮肤经常阳光暴露（OR=0.46，95%CI 0.29~0.73，P=0.001）、维生素D补充（有时补充，OR=0.33，95%CI 0.21~0.51，P<0.001；每天补充，OR=0.20，95%CI 0.11~0.36，P<0.001）和婴幼儿配方摄入（每周4~7次，OR=0.43，95%CI 0.28~0.68，P<0.001）均为儿童维生素D缺乏和不足的保护性因素。 结论： 我国11省、自治区、直辖市7岁以下儿童维生素D缺乏和不足问题普遍，年龄、阳光暴露程度、维生素D补充和婴幼儿配方摄入等因素均可影响维生素D营养状况。.