BACKGROUND Vitamin D (25(OH)D) deficiency has become an emerging public health problem due to its influence on skeletal and extraskeletal diseases. Bone health in patients with sickle cell disease (SCD) is especially compromised and they are more likely to have 25(OH)D deficiency than the general population. Despite this, there is little information on the efficacy of vitamin D3 (vitD3) prophylaxis and its role in improving bone mineral density (BMD) in this population. PROCEDURES A prospective, longitudinal, single-center study was conducted with 136 children with SCD monitored at a tertiary referral hospital for SCD. Demographic, clinical and management data, 25(OH)D levels and bone densitometries (DXA) were collected. RESULTS Eighty patients were included. There are significant differences between the means of each of 25(OH)D levels as a function of whether the patient started prophylactic treatment as an infant or not (35.71 vs. 27.89 ng/ml, respectively [p = .014]). In multivariate analysis, 800 IU daily dose was shown as a protective factor (p = .044) to reach optimal blood levels (≥30 ng/ml). According to Kaplan-Meier curves, patients younger than 10 years reached optimal levels earlier than older (p = .002), as well as those who were not being treated with hydroxyurea (p = .039). CONCLUSIONS VitD3 prophylaxis is a safe practice in SCD. It is important to start this prophylactic treatment when the child is an infant. The daily regimen with 800 IU could be more effective for reaching levels ≥30 ng/ml, and, especially in preadolescent and adolescent patients, we should raise awareness about the importance of good bone health.

中文翻译：

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镰状细胞病患儿预防性口服维生素 D（胆钙化醇）的有效性评价

背景维生素 D (25(OH)D) 缺乏症由于其对骨骼和骨骼外疾病的影响，已成为一个新出现的公共卫生问题。镰状细胞病 (SCD) 患者的骨骼健康尤其受到损害，与一般人群相比，他们更有可能缺乏 25(OH)D。尽管如此，关于维生素 D3 (vitD3) 预防的功效及其在该人群中改善骨矿物质密度 (BMD) 的作用的信息很少。程序 对在 SCD 三级转诊医院监测的 136 名 SCD 儿童进行了一项前瞻性、纵向、单中心研究。收集了人口统计学、临床和管理数据、25(OH)D 水平和骨密度测量 (DXA)。结果 包括八十名患者。作为患者是否在婴儿时期开始预防性治疗的函数，每个 25(OH)D 水平的平均值之间存在显着差异（分别为 35.71 和 27.89 ng/ml [p = .014]）。在多变量分析中，800 IU 日剂量显示为达到最佳血液水平 (≥30 ng/ml) 的保护因素 (p = .044)。根据 Kaplan-Meier 曲线，年龄小于 10 岁的患者达到最佳水平的时间早于年龄较大的患者 (p = .002)，以及未接受羟基脲治疗的患者 (p = .039)。结论 VitD3 预防是 SCD 的安全实践。当孩子还是婴儿时开始这种预防性治疗很重要。800 IU 的每日方案对于达到 ≥ 30 ng/ml 的水平可能更有效，尤其是在青春期前和青少年患者中，