Supplementary Material for: Effects of a 2-year early childhood vitamin D3 intervention on tooth enamel and oral health at age 6-7 years

Introduction: The aim of the study was to compare the effects of a 30 µg/day vs 10 µg/day vitamin D supplementation, given during the two first years of life, on oral health at the age of six to seven years. Methods: In 2013-2016, we conducted a randomized, double-blinded, clinical trial from age 2 weeks to 2 years of daily vitamin D3 supplementation (10 vs 30 µg), including 975 healthy infants. For the present follow-up study at age 6-7 years, a sample of 123 children underwent oral examination by investigators blinded to the intervention group. Tooth enamel defect and caries findings, oral rinse active matrix metalloproteinase-8 levels, and tooth eruption were recorded. The intervention groups were compared with chi-square and Mann Whitney U tests. Associations of the oral health outcomes were evaluated with correlation analysis and logistic regression. Results: Of the children (median age 7.4 years, 51% boys), 56% belonged to the 30 µg intervention group. Developmental defect of enamel (DDE) was found in 39% of the children in the 10 µg intervention group and in 53% of the 30 µg group (p = 0.104). In total, 94% of children were vitamin D sufficient (25(OH)D ≥50 nmol/l) and 88% had caries-free teeth. No associations were found between vitamin D intervention group in infancy and oral health or the presence of DDE. Conclusion: Daily supplementation with 10 µg vitamin D3 in the Northern Hemisphere seems adequate in healthy children younger than 2 years in ensuring good oral health at early school age. Trial registration: ClinicalTrials.gov (NCT04302987)

引言：本研究旨在对比生命最初两年每日补充30微克与10微克维生素D，对儿童6至7岁时口腔健康状况的影响。
方法：2013-2016年，我们针对2周至2岁的健康婴儿开展了一项随机双盲临床试验，每日补充维生素D3（10微克 vs 30微克），共纳入975名健康婴儿。针对本次6至7岁的随访研究，我们从受试者中抽取123名儿童，由对干预分组不知情的研究人员进行口腔检查。记录内容包括牙釉质缺陷与龋齿情况、漱口液中活性基质金属蛋白酶-8水平以及牙齿萌出状态。采用卡方检验与曼-惠特尼U检验对干预组进行比较，通过相关分析与logistic回归评估口腔健康结局的关联情况。
结果：本次研究的儿童中位年龄为7.4岁，其中男性占比51%，56%属于30微克干预组。10微克干预组儿童中39%存在牙釉质发育缺陷（DDE），30微克干预组这一比例为53%（p=0.104）。总体而言，94%的儿童维生素D充足（25(OH)D ≥50nmol/l），88%的儿童无龋齿。未发现婴儿时期的维生素D干预分组与口腔健康状况或牙釉质发育缺陷存在关联。
结论：在北半球，对2岁以下健康儿童每日补充10微克维生素D3，足以保障其学龄早期拥有良好的口腔健康状况。
试验注册：ClinicalTrials.gov（NCT04302987）