Department of Child and Adolescent Health, School of Public Health and Management, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region, China.
Department of Epidemiology, Indiana University Richard M. Fairbanks School of Public Health, Indianapolis, IN, USA.
Bone. 2018 Nov;116:28-34. doi: 10.1016/j.bone.2018.07.006. Epub 2018 Jul 10.
Although vitamin D is essential for bone health, little is known about prevalence of vitamin D deficiency and low bone mineral density (BMD) among children, especially those in developing countries. It also remains unclear whether serum 25-hydroxyvitamin D [25(OH)D] is associated with BMD among children. We investigated these questions among children and adolescents in Yinchuan (latitude: 38° N), Ningxia, an economically underdeveloped province in Northwest China. A total of 1582 children (756 boys and 826 girls), aged 6-18 years, were recruited from schools using the stratified random sampling method in fall 2015. Serum 25(OH)D concentrations were measured by enzyme-linked immunosorbent assay, and BMD was quantified by dual-energy X-ray absorptiometry. Vitamin D deficiency (defined as serum 25(OH)D ≤ 37.5 nmol/L) was present in 35.5% of study subjects. There were no clear patterns of differences in serum 25(OH)D concentrations across the four age groups compared (6-9 years, 10-13 years, 14-16 years, and 17-18 years). The prevalence of low total body less head (TBLH) BMD (defined as a Z-score of ≤ -2.0 standard deviations away from the mean BMD values of the Chinese pediatric reference population) among children examined was 1.8% and was not significantly different among the four age groups considered. Linear regression analysis revealed that age, weight, and height were significantly and positively associated with TBLH BMD and that the strongest determinant of TBLH BMD was age in boys and weight in girls. There were no significant correlations between serum 25(OH)D concentrations and BMD obtained for total body and at various skeletal sites (r ranged from -0.005 to 0.014) regardless of whether children evaluated were sufficient, insufficient, or deficient in vitamin D. In conclusion, more than one-third of children and adolescents in a Northwest Chinese city were deficient in vitamin D but only <2% of them developed low BMD.
尽管维生素 D 对骨骼健康至关重要，但对于儿童，尤其是发展中国家儿童的维生素 D 缺乏症和低骨密度（BMD）的流行情况，人们知之甚少。目前仍不清楚血清 25-羟维生素 D [25(OH)D] 是否与儿童 BMD 相关。我们在中国西北部经济欠发达的宁夏回族自治区银川市（纬度：38°N）的儿童和青少年中调查了这些问题。2015 年秋季，采用分层随机抽样方法，从学校招募了 1582 名年龄在 6-18 岁的儿童（男 756 名，女 826 名）。采用酶联免疫吸附试验测定血清 25(OH)D 浓度，双能 X 线吸收法测定 BMD。维生素 D 缺乏症（定义为血清 25(OH)D≤37.5nmol/L）在 35.5%的研究对象中存在。与四个年龄组（6-9 岁、10-13 岁、14-16 岁和 17-18 岁）相比，血清 25(OH)D 浓度无明显差异。检查儿童的全身非头部（TBLH）BMD 低（定义为 Z 分数低于中国儿科参考人群平均 BMD 值的-2.0 个标准差）的患病率为 1.8%，且在考虑的四个年龄组中无显著差异。线性回归分析显示，年龄、体重和身高与 TBLH BMD 呈显著正相关，男孩 TBLH BMD 的最强决定因素是年龄，女孩是体重。无论儿童维生素 D 是充足、不足还是缺乏，血清 25(OH)D 浓度与全身和各骨骼部位的 BMD 之间均无显著相关性（r 值范围为-0.005 至 0.014）。综上所述，中国西北某城市的儿童和青少年中，超过三分之一的人维生素 D 缺乏，但只有不到 2%的人 BMD 低。
