Enlarged prostate is often described as a normal part of aging. After all, almost all men will develop it as they get older.
A new study in the Journals of Gerontology suggests that it’s caused by a specific lifestyle habit.
Unfortunately, it’s a lifestyle habit of which most of us are guilty. Maybe that’s why so many men develop an enlarged prostate.
There have been hints in previous studies and from doctors that lifestyle habits such as sleep, sedentary behavior, and exercise levels could be related to this condition. Whether they really are related and the direction of the relationship are still unclear.
In response, the authors of this new study decided to do a Mendelian randomization study to clarify how the relationship works.
To understand what Mendelian randomization is, you must grasp a big limitation of most scientific studies.
Let’s say you want to find out whether a lack of sleep causes an enlarged prostate. You recruit participants with and without adequate sleep, and then you check which group has the highest enlarged prostate rate, right?
The problem is that such a study can only tell you whether the two tend to occur together. It cannot tell you which is the cause and which is the effect.
In a study based on Mendelian randomization, researchers identified people with genes that are related to poor sleep, and then they checked which ones went on to develop an enlarged prostate.
In other words, they can clearly see that poor sleep occurs first (the cause) and the enlarged prostate later (the effect).
The researchers selected people with a genetic disposition for poor sleep, sedentary lifestyles, and high physical activity from published genome-wide association studies. They then checked which ones went on to develop an enlarged prostate.
The results of the study were illuminating.
1. Short sleep duration caused enlarged prostate. With every standard deviation of increase in sleep duration, the participants’ risk of developing an enlarged prostate declined by 58%.
2. Enlarged prostate did not cause short sleep duration.
3. Sedentary behavior and different levels of physical exercise were not related to an enlarged prostate.
This is somewhat counterintuitive. Because enlarged prostate causes frequent urination during the night, one would assume that the poor sleep is a result of the enlarged prostate.
This study shows that it is precisely the other way around. If you want to figure out how to avoid an enlarged prostate, you may want to improve your sleep first.