Marijuana and sperm quality
According to data obtained by Harvard University scientists working under the guidance of Associate Professor George Chavarro, men who have ever smoked marijuana have a significantly higher concentration of sperm compared to men who have never done it. At the same time, there were no significant differences in the concentration of sperm in men who continue and previously stopped using marijuana.
According to statistical estimates, 16.5% of the adult population of the United States smokes marijuana, while in recent years the use of this drug for personal purposes is increasingly legalized. Due to the growing popularity of the idea of the harmlessness of marijuana, understanding the effects actually exerted by its active components on human health is an extremely important task today.
Researchers have suggested that smoking marijuana may be associated with a deterioration in sperm quality. The results of earlier studies indicate that it has a negative impact on the reproductive health of men, but most of these studies were conducted on animal models or with the participation of men with a history of substance abuse.
As part of their study, the authors collected 1,143 sperm samples from 662 men between 2000 and 2017. The average age of the participants was 63 years, while most of them had college-level education. In addition, 317 participants provided blood samples analyzed for the content of sex hormones. To collect information about smoking marijuana, the researchers used questionnaires in which participants answered a number of questions, including whether they had smoked more than two marijuana cigarettes or an equivalent amount of marijuana throughout their lives and whether they continued to smoke marijuana at the time of the study.
365 (35%) participants confirmed smoking marijuana at some stage of life. Of these, 44% claimed that they had completely given up "weed", while 11% confirmed that they continue to smoke.
According to the results of semen analysis, men who have ever smoked marijuana had an average sperm concentration of 62.7 million per milliliter of ejaculate, while for those who have never smoked, this figure was only 45.4 million. At the same time, only 5% of men who smoked marijuana had a sperm concentration below 5 million per milliliter (the lower value of the normal range, according to WHO), and for the comparison group this indicator was 12%.
In addition, it turned out that more active smoking of marijuana is associated with increased levels of testosterone in the blood serum.
The authors note that the collected data have a number of potential limitations, including the silencing of information about smoking marijuana, which is a prohibited drug. They also emphasize that they do not know to what extent the revealed pattern can be extrapolated to the general population, since the examined sample included men with reproductive insufficiency who sought help from the infertility treatment center. Another difficulty is the lack of an opportunity to assess the reliability of the results, since until now there have been practically no such studies.
According to the authors, the results obtained completely contradict the original hypothesis. However, they have two logical interpretations. Firstly, in small doses, marijuana can promote spermatogenesis by influencing the endocannabinoid system involved in fertility mechanisms, but this beneficial effect is lost when the dose is increased. No less logical is the interpretation that men with higher testosterone levels are more prone to risky behavior, including smoking marijuana. In any case, the results of the study should be interpreted with great caution, and the effect of marijuana on health requires further study.
Article by Feiby L. Nassan et al. Marijuana smoking and markers of testicular function among men from a fertility center is published in the journal Human Reproduction.
Evgenia Ryabtseva, portal "Eternal Youth" http://vechnayamolodost.ru based on Harvard T.H. Chan School of Public Health: Marijuana smoking linked with higher sperm concentrations.