How to Avoid Prostate Cancer?

Summarized by Robert W. Griffith, MD
June 4, 2004

Introduction

There have been conflicting reports about whether the frequency of sexual activity influences the likelihood of a man developing prostate cancer. Increased activity may be due to more testosterone, which is believed to increase the risk. Alternatively, men who are especially sexually active are more likely to acquire a sexually transmitted disease (STD); these are also supposed to increase the likelihood of prostate cancer.

Against this background comes a new report from the US National Cancer Institute. It's just been published in the Journal of the American Medical Association, and is summarized here.

What was done

Over 50,000 male health professionals between 40 and 75 were enrolled in 1996 in the Health Professionals Follow-up Study. They completed questionnaires about their possible risk factors for cancer and other chronic diseases every two years. In 1992 the questionnaire included questions about the frequency of ejaculation (this covered ejaculation related to intercourse, nocturnal emissions ['wet dreams'] and masturbation).

About 30,000 men provided adequate information on this topic, and these were followed carefully for the next 8 years. They were asked to report the average number of ejaculations they had per month during their twenties, their forties, and during the previous year (i.e. 1991); they could reply 1 to 3, 4 to 7, 8 to 12, 13 to 20, or 21-or-more ejaculations per month.

Subsequent questionnaires asked whether the participant had been diagnosed with prostate cancer; if the man replied "yes", he received further enquiries to make sure of the diagnosis.

What was found

During the follow-up period, 1449 cases of prostate cancer were diagnosed. As expected, the participants' average number of ejaculations per month fell with increasing age, from 15 a month in their twenties, to 5 a month for those over 60. Put another way, 58% of them reported 3 or more ejaculations a week in their twenties, falling to 32% in their forties, 22% in their fifties, and 5% in the over 60-year-olds.

Men who ejaculated more often over their lifetime tended to be physically more active, and were more likely to have had an STD, prostatitis, or a vasectomy. They were also more likely to be divorced or separated, and consume more total calories, lycopene, fish, alcohol, and supplemental vitamin E and zinc.

The 'relative risk', or likelihood, of someone developing prostate cancer was determined for the different rates of ejaculation in the different age periods. This calculation was made after adjusting for a large number of possible interfering factors - age, race, family history of prostate cancer, vasectomy, BMI, height, smoking, type 2 diabetes, physical activity, and various dietary factors. With the likelihood of cancer set at 1.00 for ejaculation rates of 4 to 7 times a month, the likelihood for other rates was as follows:

*statistically significant (i.e. the difference is not due to chance alone)

	Number of Ejaculations Per Month
	0-3	4-7	8-12	13-20	21 and over
Age 20-29	1.09	1.00	1.06	0.95	0.89
Age 40-49	0.83	1.00	0.96	0.98	0.68*
Previous year	1.06	1.00	1.06	1.07	0.49*
Lifetime	0.89	1.00	0.89	0.86*	0.67*

It can be seen that for those with an ejaculation rate of over 20 times a month during the previous year, the risk of prostate cancer was more than halved. For people who had a rate of over 20 times a month in their forties, or over their whole lifetime, the risk was reduced by about 30%. And for those with a frequency of over 13 times a month over their lifetime, the risk was reduced by 20%.

What does this mean?

This study shows that a higher ejaculation frequency is not associated with an increased risk of prostatic cancer; on the contrary, it may be linked to a decreased risk. The findings can't be explained by interference of known risk factors such as age, family history, STD, smoking, or diet.

Why should this be so? The doctors who did the study suggest that frequent ejaculation may alter the prostatic fluid found in the gland so that it contains fewer chemical carcinogens, which are known to accumulate there. Alternatively, frequent sexual activity may reduce the development of microscopic crystals within the prostate, which also have been reported in connection with prostate cancer.

As we said at the start of this article, there have been conflicting reports of possible links between increased sexual activity and the likelihood of prostate cancer. We believe the present study should be confirmed in another trial, before the results are accepted as gospel. In the meantime, there are two steps you can take to reduce your risk of getting prostate cancer. First, avoid a diet high in animal fat diet (meat, cheese, high-fat dairy produce); this has been shown to be linked to an increased risk. And second, eat more tomatoes! (See the first related link below).

Source

• Ejaculation frequency and subsequent risk of prostate cancer. MF. Leitzmann, EA. Platz, MJ. Stampfer,  et al., JAMA, 2004, vol. 291, pp. 1578--1586

Related Links
Tomatoes Really Do Reduce Prostate Cancer Risk
Fish May Reduce Prostate Cancer Risk

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