Effect of calcium and vitamin D on growth, rickets and Kashin–Beck disease in 0‐ to 5‐year‐old children in a rural area of central Tibet

Objective To evaluate the effect of calcium (15 mmol/day) and vitamin D (625 μg/month), as single supplement or in combination, vs. no supplement on growth, clinical signs of rickets and Kashin–Beck disease (KBD) and dental health. Methods Prospective controlled trial involving children aged 0–5 years living in four groups of villages in a KBD‐endemic rural area of central Tibet who received either calcium and/or vitamin D or no supplement. The cohort was followed over 3 years. Primary outcome was the impact of the different supplementation regimes on KBD, rickets and growth; secondary outcomes were impact on urinary levels of calcium and phosphorus, biomarkers of bone and cartilage turnover, and dental health. Results No difference was observed between the four groups with regard to anthropometric data, rickets, KBD, urinary levels of CrossLaps® and CartiLaps®. Weight for height or age, mid‐upper arm circumference and skinfold thickness decreased in the four groups. Height for age increased and the prevalence of KBD fell in the four groups. Dental health was better in the group receiving calcium and vitamin D. Urinary calcium levels increased after 3 years of follow‐up in all groups; the group receiving vitamin D had a higher increase (P‐value: 0.044). The same global increase was observed for urinary phosphorus levels; the group receiving calcium had a higher increase (P‐value: 0.01). Conclusions Calcium and vitamin D failed to improve growth and bone metabolism of children living in a KBD‐endemic rural area. Calcium and vitamin D supplementation improved dental health. Objectif Evaluer l'effet du calcium (15 mmol/jour) et de la vitamine D (625 μg/mois), comme supplément unique ou en combinaison, par rapport à aucun supplément sur la croissance, les signes cliniques du rachitisme et de la maladie de Kashin‐Beck (KBD) et la santé dentaire. Méthodes Essai contrôlé prospectif impliquant des enfants âgés de 0 à 5 ans vivant dans 4 groupes de villages dans une zone rurale endémique pour la KBD dans le centre du Tibet qui ont reçu soit du calcium et/ou de la vitamine D ou aucun supplément. La cohorte a été suivie sur 3 ans. Le principal résultat a été l'impact des différents régimes de supplémentation sur la KBD, le rachitisme et la croissance; les résultats secondaires étaient l'impact sur les taux urinaires de calcium et de phosphore, biomarqueurs de l'os et du renouvellement du cartilage, et la santé dentaire. Résultats Aucune différence n'a été observée en