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- Published on: 23 November 2015
- Published on: 23 November 2015
- Published on: 23 November 2015
- Published on: 23 November 2015
- Published on: 23 November 2015
- Published on: 23 November 2015Re:No evidence that oral contraceptive use is associated with prostate cancer mortality: further observationsShow More
We thank Drs Cherrie and MacCalman for their thoughtful comments. However the first step in any analysis is exploring the variables. When examining the distribution of women use of vaginal barriers world- wide, one notices that no country reports more than 5% of woman using this mode of contraception, and only 9 countries have over 1% use of vaginal barriers. Clearly this variable cannot be entered at face value. When w...
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None declared. - Published on: 23 November 2015No evidence that oral contraceptive use is associated with prostate cancer mortality: further observationsShow More
We are pleased that Margel and Fleshner recognize the data errors in their original manuscript [1], which have a dramatic impact on the outcome of the ecological analysis [2]. Using the correct dataset and extending the analysis to include all countries, which we agree is appropriate, the authors report that the correlation between oral contraceptive use and prostate cancer mortality was much reduced (Pearson correlation...
Conflict of Interest:
None declared. - Published on: 23 November 2015Re:Oral contraceptive use is not associated with prostate cancerShow More
We are thankful for Dr Cherrie`s astute observations. After careful review of our data it appears that we indeed miscoded several points in our data set, which have resulted in an error in the analysis. We therefore decided to make sure our hypothesis is in reality supported by the data. We re-analyzed the correlation between mode of contraceptive use and prostate cancer (PCa)- using data from all countries available on t...
Conflict of Interest:
None declared. - Published on: 23 November 2015Oral contraceptive use is not associated with prostate cancerShow More
Margel and Fleshner (1) present results from an ecological study of associations between oral contraceptive (OC) use and prostate cancer. They hypothesize that men inadvertently ingest OCs or their by-products, passed from female urine into the environment or drinking water, and that the consequent increased low-level oestrogen exposure causes prostate cancer. The authors used data from a stratified random sample of countr...
Conflict of Interest:
None declared. - Published on: 23 November 2015This ecological study overlooked well known prostate cancer risk-modifying factorsShow More
The paper by Margel and Fleshner reporting a direct correlation between oral contraceptive use and prostate cancer incidence and mortality rates1 is interesting and there may be an effect of oral contraceptive use on risk of prostate cancer. However, the study was not conducted according to the general rules for such studies. While ecological studies are a very useful approach for determining links to cancer (e.g., Ref. 2),...
Conflict of Interest:
None declared.