DataSheet_1_Vitamin D Supplementation Improves Handgrip Strength in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.doc

IntroductionIn postmenopausal women, vitamin D deficiency (as defined by the circulating level of 25(OH)D being below 20 ng/ml (50 nmol/L)) is a regular occurrence. The effect of vitamin D supplementation on the muscle function of postmenopausal women has been controversial. This systematic review and meta-analysis of randomized controlled trials (RCTs) examines and summarizes the effects of vitamin D supplementation on the muscular strength and mobility of postmenopausal women.
MethodsRCTs that met the inclusion criteria for this study were identified by searching PubMed, EMBASE, and the Cochrane Library. Postmenopausal women who were included in the study were exposed to RCTs assessing the effectiveness of vitamin D supplements. Meta-analysis data were extracted by two independent reviewers and screened for methodological quality. RCTs that did not meet the minimum requirement for assessment were excluded. In the meta-analysis, the effect size (weighted mean differences, WMD) of handgrip strength (HGS) and timed-up and go test (TUG) with a 95% confidence interval (CI) was obtained to compare reported results across the included RCTs.
ResultsA total of 19 trials were included in this systematic review, among which 13 trials were eligible for the meta-analysis. In the 13 included studies, supplementing with vitamin D produced a weighted mean difference of 0.876 kg (95% CI = 0.180 to 1.571, P = 0.014, I2 = 68.5%) for HGS, a measurement of muscle strength. However, an insignificant decrease of 0.044 s was observed after analyzing the TUG (95% CI = -0.979 to 0.892, P = 0.927, I2 = 95%). According to subgroup analysis, vitamin D supplementation increased HGS in patients over the age of 60 (P = 0.001), in those without calcium supplementation (P = 0.032), and in those whose baseline vitamin D level was greater than 75 nmol/L (30 ng/ml) (P = 0.003).
ConclusionsTaking into account the studies in this systematic review, vitamin D supplementation improved muscle strength in postmenopausal women. However, an insignificant result was demonstrated in terms of mobility after vitamin D supplementation.

引言：绝经后女性中，维生素D缺乏（定义为循环中25-羟维生素D[25(OH)D]水平低于20 ng/ml（50 nmol/L））的情况颇为常见。补充维生素D对绝经后女性肌肉功能的影响迄今仍存在争议。本项针对随机对照试验（randomized controlled trials, RCTs）的系统评价与荟萃分析，旨在探讨并总结补充维生素D对绝经后女性肌肉力量与活动能力的影响。
方法：通过检索PubMed、EMBASE及Cochrane图书馆，筛选符合本研究纳入标准的随机对照试验。本研究纳入的受试对象为绝经后女性，这些受试者均接受了评估维生素D补充剂有效性的随机对照试验干预。由两名独立研究者提取荟萃分析所需数据，并对纳入研究的方法学质量进行筛查；未达到最低评估要求的随机对照试验将被排除。在本次荟萃分析中，我们提取了握力（handgrip strength, HGS）与计时起立行走测试（timed-up and go test, TUG）的效应量——加权均数差（weighted mean differences, WMD）及95%置信区间（confidence interval, CI），以对比纳入的各随机对照试验的报告结果。
结果：本项系统评价共纳入19项试验，其中13项符合荟萃分析的纳入标准。在纳入的13项研究中，补充维生素D可使作为肌肉力量评估指标的握力出现加权均数差0.876 kg（95%置信区间：0.180~1.571，P=0.014，I²=68.5%）。然而，针对计时起立行走测试的分析显示，其结果仅出现无统计学意义的0.044秒小幅下降（95%置信区间：-0.979~0.892，P=0.927，I²=95%）。亚组分析结果表明，在年龄超过60岁的受试者、未联合补钙的受试者以及基线维生素D水平高于75 nmol/L（30 ng/ml）的受试者亚组中，补充维生素D可显著提升握力（对应P值分别为0.001、0.032及0.003）。
结论：综合本项系统评价纳入的所有研究结果，补充维生素D可改善绝经后女性的肌肉力量。但就活动能力指标而言，补充维生素D未产生具有统计学意义的改善效果。