Example of a vitamin D meta-analysis which ignored the data
We never cease to be amazed at the stupidity of some meta-analysis
Sometimes they take no account of the IUs of vitamin D taken by each of the trials they are analyzing
Example: Vitamin D and gestational diabetes: a systematic review and meta-analysis
European Journal of Internal Medicine 2012
The authors ignore that there was no statistical difference in vitamin D levels in three trials
Farrant, Makgoba, and Baker stated that they had NO statistical difference between the two arms
YET, this meta-analysis included the data from those trials
If we ignore the data from those 3 trials it appears that the odd ratio would increase to about 2.4 from 1.6
If the authors had actually gotten around to consider the vitamin D levels actually measured by each of the trials
and weighted the data based of each based on the vitamin D levels (rather than no weighting at all)
the odds ratio would most likely had been far higher - perhaps >3
Farrant study is attached at the bottom of this page
Notes:
The vitamin D levels were so low that they did not detect any difference in Gestational Diabetes
The vitamin D levels were so low that they did not detect any difference in neonate size
They compared ALL mothers to those mothers less than 20 nanograms,
- rather than the conventional comparison of those above to those below some level, say 20 nanograms
- Something is strange with the Farrant study.
- The women taking vitamin D supplements had lower level blood levels of vitamin D
- Wonder if the mothers were taking vitamin D2 instead of vitamin D3