Dear all,
In this meta-analysis (https://www.ncbi.nlm.nih.gov/pubmed/30475963) it seems that for instance in figure 2 for lean body mass improvements individual studies did not find significant better results with protein supplementation compared to no protein supplementation (since the interval lines crosses the 0 line).
For example: Mitchell et al https://academic.oup.com/ajcn/article/106/6/1375/4823157 crosses the line while you can find a significant interaction effect in the article of Mitchell et al, see table 3. The time effect was also significant but the diet effect not. Is the absent diet effect the reason why the study of Mitchell et al. crosses the 0 line in the meta-analysis? Or is it because the authors used SMD (standardized mean difference) which is more relative and uses the pooled standard deviation? (since SMD = (new treatment improvement - placebo improvement) / pooled standard deviation. Or has the small sample size of the study influence on this result?
I got confused because normally you see the significant results from the individual studies reflected in the meta-analyses right? But maybe that is only the case for absolute effect sizes and not SMD? I tried to find information about this on the internet but I could not find it. I hope you can help.
FYI: I added the pdf's of the mentioned articles in the appendix.
Thank you in advance!
In this meta-analysis (https://www.ncbi.nlm.nih.gov/pubmed/30475963) it seems that for instance in figure 2 for lean body mass improvements individual studies did not find significant better results with protein supplementation compared to no protein supplementation (since the interval lines crosses the 0 line).
For example: Mitchell et al https://academic.oup.com/ajcn/article/106/6/1375/4823157 crosses the line while you can find a significant interaction effect in the article of Mitchell et al, see table 3. The time effect was also significant but the diet effect not. Is the absent diet effect the reason why the study of Mitchell et al. crosses the 0 line in the meta-analysis? Or is it because the authors used SMD (standardized mean difference) which is more relative and uses the pooled standard deviation? (since SMD = (new treatment improvement - placebo improvement) / pooled standard deviation. Or has the small sample size of the study influence on this result?
I got confused because normally you see the significant results from the individual studies reflected in the meta-analyses right? But maybe that is only the case for absolute effect sizes and not SMD? I tried to find information about this on the internet but I could not find it. I hope you can help.
FYI: I added the pdf's of the mentioned articles in the appendix.
Thank you in advance!
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