Diet, dairy products, vitamin D, and prostate cancer risk
Posted Sep 28 2008 1:49pm
The “New” Prostate Cancer InfoLink is projecting media headlines over the next few days that scream, “Milk Does NOT Cause Prostate Cancer,” based on a recent meta-analysis of data from over 25,000 men enrolled in observational studies. However, this is not exactly what the recent study shows!
Huncharek et al. have reported a sophisticated statistical analysis of pooled data from 45 observational studies in order to assess the available evidence related to the consumption of dairy products, calcium, and vitamin D and the risk of prostate cancer. The 45 studies included data from a total of 26,769 men.
Statistical issues in this sort of retrospective analysis are always complex, and those who are interested in the actual statistical analysis are advised to read the original paper. The authors state the following results:
There was no evidence of any association between dairy product or milk intake and risk of prostate cancer.
Case-control analyses using calcium as the exposure of interest demonstrated no association with increased risk of prostate cancer.
Dietary intake of vitamin D also was not related to prostate cancer risk
The authors conclude that “data from observational studies do not support an association between dairy product use and an increased risk of prostate cancer.”
The “New” Prostate Cancer InfoLink considers this study to be a careful, academic, retrospective, statistical analysis of available observational data regarding a possible correlation between dairy product intake and risk for prostate cancer. We do not consider this study to have any meaningful, projectible value. In other words, one absolutely should not interpret this analysis to mean that there isn’t a correlation between eating dairy products and prostate cancer.
Look at the careful wording used by the authors in stating their results and conclusions. All they are telling us is that this analysis doesn’t demonstrate such a correlation. However, this probably won’t stop the media from using this data to tell us that dairy products don’t cause prostate cancer. After all, if you are one of the big dairy product companies, this study is a marketing godsend!