婴幼儿期维生素D补充与一年级小学生超重肥胖的纵向关联

  目的  调查婴幼儿期维生素D补充状况及其对学龄初期超重肥胖的影响，为儿童肥胖的早期预防提供新思路。  方法  以8 744名上海市闵行区2019年9月1日入学，且于2019年10月8日至2020年1月17日进行了常规体检的小学一年级学生为研究对象，由专业医务人员按标准的方法和仪器测量儿童的身高、体重并计算体质量指数(BMI)，以BMI界定超重肥胖，并回溯收集其出生记录与婴幼儿期维生素D补充、婴幼儿期喂养记录。采用非条件Logistic回归模型，拟合婴幼儿期维生素D补充对学龄初期超重肥胖的影响，并进一步根据出生后1，4，6月龄内是否纯母乳喂养进行分层分析。  结果  上海市闵行区一年级学生中，超重肥胖率为32.5%(2 843名)；出生后1，2，4，6月龄内的婴儿维生素D补充率分别为20.2%，49.7%，66.3%，72.7%，有83.2%的婴幼儿在出生后3年内补充了维生素D。出生后1月龄内补充过维生素D的婴幼儿，学龄初期发生超重肥胖的风险降低(OR=0.82, 95%CI=0.68~0.98)；分层分析结果显示，此保护作用在1，4，6月龄内为纯母乳喂养的婴儿中尤其明显OR(95%CI)=0.76(0.61~0.97)，0.76(0.59~0.99)，0.69(0.49~0.98)，P值均 < 0.05]。  结论  婴幼儿期维生素D补充率有待提高，婴幼儿期维生素D补充尤其对纯母乳喂养儿有降低学龄初期超重肥胖风险的作用。

Longitudinal association between vitamin D supplementation in infancy and overweight or obesity among first-grade primary school pupils

  Objective  To investigate the current status of vitamin D supplementation in infancy and to explore the effect of vitamin D supplementation in infancy and overweight or obesity in early school years.  Methods  Tollay 8 744 first-grade elementary school students in Minhang District, Shanghai, who entered school on September 1st, 2019, and had a routine physical examination in that year, were enrolled in the study. Children's height and weight were measured by medical professionals according to standard methods and instruments, and overweight or obesity was defined by BMI. Birth records, vitamin D supplementation during infancy, and feeding records during infancy were collected retrospectively. An unconditional Logistic regression model was used to evalute the effect of vitamin D supplementation in infancy on overweight or obesity in early school age. Stratified analysis was performed according to whether they were exclusively breastfed within 1, 4, 6 month of birth or not.  Results  The overweight or obesity rate of first grade students in Minhang District, Shanghai was 32.5%(2 843/8 744). Retracing their vitamin D supplementation during infancy, the vitamin D supplementation rates were 20.2%, 49.7%, 66.3%, and 72.7% for infants 1, 2, 4, and 6 months of age after birth, respectively, and 83.2% of infants and toddlers were supplemented within 3 years of birth. Infants who were supplemented with vitamin D within 1 month of birth had a reduced risk of overweight and obesity in early school age (OR=0.82, 95%CI=0.68-0.98), and stratified analysis showed that this protective effect was only present in infants who were exclusively breastfed at 1, 4, and 6 months of age OR(95%CI)=0.76(0.61-0.97), 0.76(0.59-0.99), 0.69(0.49-0.98), P < 0.05].  Conclusion  The rate of vitamin D supplementation in infancy needs to be improved, and vitamin D supplementation in infancy may have a protective effect on the development of overweight and obesity in exclusively breastfed children in early school years.