Summer time is here. Time for healthy activities like swimming, tennis, bicycle rides……. Or is it? A recent study from the UK published in the Journal of Men’s Health states that cycling is associated with an increased risk of prostate cancer.
Apparently the popularity of cycling is increasing in Great Britain and the overwhelming majority of cyclists are men. A study in the UK of over 5000 cyclists (average age 48, age range 16 to 88) examined the relationship between cycling, infertility, erectile dysfunction and prostate cancer. Data was obtained by response to an online survey; over 2000 respondents were over 50 years of age.
The incidence of both infertility and prostate cancer in this population was 1% and for ED 8%. Specifically in men 50 and older, the incidence of prostate cancer correlated to the amount of time the individual spent bike riding with men who biked 4-8 hours a week having three times the incidence of those who biked less than 4 hours a week, and six times higher it they biked more than eight hours a week.
However, the study fails to explain the possible link between Prostate cancer and bicycling. After all, if the link is valid, one might expect that countries that have heavy bicycle use such as China to have a much higher incidence of prostate cancer; but actually the incidence is lower.
Could there be something else behind the association in their data set?
It has been previously published that bicycle riding can raise PSA levels. PSA is used as a screen for prostate cancer, so it is conceivable that men with higher PSAs may have had an earlier diagnosis of their prostate cancer.
Another consideration is that the data set is actually very small. Overall, 36 of the 2027 men over age 50 or about 1.8% had prostate cancer, but the percentage of 50-year-old men in a comparable population who will develop prostate cancer over a 10-year period is 2.3 percent.
Therefore, just as the link between Vasectomy and prostate cancer remains in doubt (as I wrote in my last blog), so does the link between bicycle riding and prostate cancer.
On the brighter side, the same study also disputes the previous reports of a link between male infertility and cycling as well as erectile dysfunction (ED) and cycling. The reports failed to find a link to ED even in men that cycled more than eight hours a week.