PROFITH "PROmoting FITness and Health through Physical Activity" Research Group, Sport and Health University Research Institute (iMUDS), Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, 18071 Granada, Spain.
Growth, Exercise, Nutrition and Development Research Group, University of Zaragoza, 50009 Zaragoza, Spain.
Nutrients. 2019 Nov 14;11(11):2760. doi: 10.3390/nu11112760.
The association between vitamin D [25(OH)D] and bone health has been widely studied in children. Given that 25(OH)D and bone health are associated with muscular fitness, this could be the cornerstone to understand this relationship. Hence, the purpose of this work was to examine if the relation between 25(OH)D and areal bone mineral density (aBMD) was mediated by muscular fitness in children with overweight/obesity. Eighty-one children (8-11 years, 53 boys) with overweight/obesity were included. Body composition was measured with dual energy X-ray Absorptiometry (DXA), 25(OH)D was measured in plasma samples and muscular fitness was assessed by handgrip and standing long jump tests (averaged z-scores were used to represent overall muscular fitness). Simple mediation analyses controlling for sex, years from peak height velocity, lean mass and season were carried out. Our results showed that muscular fitness z-score, handgrip strength and standing long jump acted as mediators in the relationship between 25(OH)D and aBMD outcomes (percentages of mediation ranged from 49.6% to 68.3%). In conclusion, muscular fitness mediates the association of 25(OH)D with aBMD in children with overweight/obesity. Therefore, 25(OH)D benefits to bone health could be dependent on muscular fitness in young ages.
维生素 D [25(OH)D] 与骨骼健康之间的关系在儿童中已经得到了广泛的研究。鉴于 25(OH)D 和骨骼健康与肌肉健康有关，这可能是理解这种关系的基石。因此，本研究的目的是探讨超重/肥胖儿童中 25(OH)D 与骨矿物质密度（aBMD）之间的关系是否通过肌肉健康来介导。研究纳入了 81 名超重/肥胖儿童（8-11 岁，53 名男孩）。采用双能 X 射线吸收法（DXA）测量身体成分，用血浆样本测量 25(OH)D，用握力和立定跳远测试评估肌肉健康（使用平均值 z 分数来表示整体肌肉健康）。进行简单的中介分析，控制性别、达到峰值身高速度后的年数、瘦体重和季节。结果显示，肌肉健康 z 分数、握力和立定跳远在 25(OH)D 与 aBMD 结果之间的关系中起中介作用（中介百分比范围为 49.6%至 68.3%）。结论：肌肉健康介导了超重/肥胖儿童中 25(OH)D 与 aBMD 的关联。因此，在儿童时期，25(OH)D 对骨骼健康的益处可能依赖于肌肉健康。
