Randomised regulated examples from hydroxyapatite since a nutritional supply of calcium had been provided because it’s produced from bone possesses other nutrients, hormone, necessary protein, and you may amino acids plus calcium. That journalist (WL otherwise MB) screened titles and you can abstracts, and two authors (WL, MB, otherwise VT) individually processed the full text message regarding potentially associated studies. This new move out-of articles try shown in profile A beneficial in the appendix 2.
Investigation removal and synthesis
We removed advice from each study from participants‘ features, data design, investment resource and you may issues of interest, and BMD in the lumbar spine, femoral neck, full cool, forearm, and total looks. BMD is measured in the multiple sites throughout the forearm, although the 33% (1/3) radius is most frequently made use of. For each research, i made use of the stated data toward forearm, aside from website. If multiple webpages was stated, i utilized the research on the sites web de rencontres seniors gratuits website nearest on 33% radius. Just one blogger (VT) removed analysis, that have been featured by the the second writer (MB). Chance of bias was analyzed just like the needed regarding the Cochrane Handbook.11 People inaccuracies have been fixed as a result of discussion.
The primary endpoints were the percentage changes in BMD from baseline at the five BMD sites. We categorised the studies into three groups by duration: one year was duration <18 months; two years was duration ?18 months and ?2.5 years; and others were studies lasting more than two and a half years. For studies that presented absolute data rather than percentage change from baseline, we calculated the mean percentage change from the raw data and the standard deviation of the percentage change using the approach described in the Cochrane Handbook.11 When data were presented only in figures, we used digital callipers to extract data. In four studies that reported mean data but not measures of spread,12 13 14 15 we imputed the standard deviation for the percentage change in BMD for each site from the average site and duration specific standard deviations of all other studies included in our review. We prespecified subgroup analyses based on the following variables: dietary calcium intake v calcium supplements; risk of bias; calcium monotherapy v CaD; baseline age (<65); sex; community v institutionalised participants; baseline dietary calcium intake <800 mg/day; baseline 25-hydroxyvitamin D <50 nmol/L; calcium dose (?500 v >500 mg/day and <1000 v ?1000 mg/day); and vitamin D dose <800 IU/day.
Analytics
We pooled the data using random effects meta-analyses and assessed for heterogeneity between studies using the I 2 statistic (I 2 >50% was considered significant heterogeneity). Funnel plots and Egger’s regression model were used to assess for the likelihood of systematic bias. We included randomised controlled trials of calcium with or without vitamin D in the primary analyses. Randomised controlled trials in which supplemental vitamin D was provided to both treatment groups, so that the groups differed only in treatment by calcium, were included in calcium monotherapy subgroup analyses, while those comparing co-administered CaD with placebo or controls were included in the CaD subgroup analyses. We included all available data from trials with factorial designs or multiple arms. Thus, for factorial randomised controlled trials we included all study arms involving a comparison of calcium versus no calcium in the primary analyses and the calcium monotherapy subgroup analysis, but only arms comparing CaD with controls in the CaD subgroup analysis. For multi-arm randomised controlled trials, we pooled data from the separate treatment arms for the primary analyses, but each treatment arm was used only once. We undertook analyses of prespecified subgroups using a random effects model when there were 10 or more studies in the analysis and three or more studies in each subgroup and performed a test for interaction between subgroups. All tests were two tailed, and P<0.05 was considered significant. All analyses were performed with Comprehensive Meta-Analysis (version 2, Biostat, Englewood, NJ).