Researchers studied alcohol drinking and prostate cancer risk. To do so, they used data from 11,372 male participants in the Finnish Twin Cohort. The Cohort was first formed in 1974. It consisted of twins who were at least 16 years old. They included both monozygotic and dizygotic twin pairs. That is, both identical and non-identical twins. All were selected from the Finnish Central Population Register.
The twins were followed for prostate cancer from 1981 to 2012. During that time, 601 individuals developed the disease. Of those, 110 died from it.
Researchers related reported abstention, average alcohol consumption and binge drinking to the risk of prostate cancer. They also related it to death from the disease.
Drinking and Prostate Cancer Results
Those who abstained from alcohol, drank heavily, or binged had higher risk than moderate drinkers.
The researchers also evaluated the risks of prostate cancer among alcohol-discordant twins. That is, among twin pairs in which the siblings did not share the same drinking pattern. Among this sub-group, the lowest risk lowest risk was among moderate drinkers who did not binge. Abstainers had a higher risk than moderate drinkers.
The results suggest a U or J-shaped relationship between drinking and prostate cancer risk.
Twin studies are very useful in medical research. For simplicity, let’s focus on identical twins. They share identical genetic makeup, were formed in the same womb, share the same birthday, etc. Also, they have the same parents, generally live in the same house, have the same socio-economic status, etc. Of course, they don’t have identical environments, especially as adults.
But having participants with the same genetics and very similar environments provides strong medical evidence. It’s very useful in determining what causes a disease.
Assume we have 100 pairs of male twins. In each pair, one brother abstains and the other drinks in moderation. Also assume that in 80 of the pairs, the brother who abstains developed prostate cancer. This would be strong evidence that drinking in moderation reduces risk of the disease.
We can be more confident because we have largely ruled out alternative explanations for the risk. It clearly is not genetic. It’s probably not environmental. And it’s probably not because of differences in socio-economic status.
Of course, we can never prove that drinking in moderation reduces the risk of prostate cancer. Similarly, we can never prove that smoking causes lung cancer. But our confidence in a causal relationship can be virtually 100%. That’s if, among other things, the evidence:
- Comes from strong research (such as twin studies).
- Is virtually all supportive of the relationship.
- Comes from studies funded by different sponsors.
- Occurs in different racial, ethnic, religious, and other groups.
- Comes from studies using different methodologies.
- Is consistent with established scientific medical knowledge.
This well-conducted study adds to the increasing evidence that drinking in moderation reduces the risk of prostate cancer.
Source: Dickerman, B., et al. Alcohol intake, drinking patterns, and prostate cancer risk and mortality. A 30-year prospective cohort study of Finnish twins. Cancer Causes Control, 2016, 27, 1049’“1058. DOI 10.1007/s10552-016-0778-6.
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