15 November 2011

Contraceptive pill to blame for rise in prostate cancer?

by Will Parker

Intriguing new findings from Canadian researchers link rates of prostate cancer around the globe to environmental estrogen pollution caused by the contraceptive pill. The researchers, David Margel and Neil Fleshner, from Toronto University, make the case for their hypothesis in the British Medical Journal.

Margel and Fleshner used data from the International Agency for Research on Cancer and the United Nations World Contraceptive Use report to pinpoint rates of prostate cancer (and associated deaths) and the proportion of women using various methods of contraception. They then analyzed the data for individual nations to identify any link between use of the Pill and prostate cancer.

The results indicated that use of IUDs, condoms or other vaginal barriers was not associated with an increased risk of prostate cancer. But, the use of the Pill in the population as a whole was significantly associated with both the number of new cases of - and deaths from - prostate cancer in countries around the world. Interestingly, the findings were not affected by a nation's standard of living.

Margel and Fleshner stress that their research is speculative and does not indicate a direct causal relationship. "[The] analysis does not confirm cause and effect, and therefore definitive conclusions cannot be drawn, as yet," they caution.

However, their paper does note that several recent studies have suggested that estrogen exposure may boost the risk of prostate cancer. Excess estrogen exposure is known to cause cancer, and it is thought that widespread use of the Pill might raise environmental levels of the metabolic by-products of the Pill.

Such endocrine disruptive compounds (EDCs) don't break down easily, so they are passed into the urine and end up in the drinking water supply or the food chain, exposing the general population, suggest the authors. "Increases in the incidence of certain cancers in hormonally sensitive tissues [breast, testis and prostate] in many parts of the industrialized world are often cited as evidence that widespread exposure of the general population to EDCs has had adverse impacts on human health," they conclude.

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Source: British Medical Journal