Use of e-cigarettes associated with lower sperm counts in a cross-sectional study of young men from the general population.

Introduction:
This text discusses the results of a cross-sectional study investigating the association between e-cigarette use, snuff use, and reproductive hormone levels and semen quality in young men from the general population. The study also compares the results with the effects of cigarette and marijuana use.

Key points:

* The study included 2008 men, with data on e-cigarette and snuff use available from 1221 men.
* approximately half of the men were cigarette smokers, 13% used e-cigarettes, 25% used snuff, and 33% used marijuana.
* Users of e-cigarettes and marijuana were often also cigarette smokers.
* Compared to non-users, daily e-cigarette users had significantly lower total sperm count, as did daily cigarette smokers.
* Cigarette smoking men had higher total and free testosterone levels compared to non-smokers, but e-cigarette users did not.
* Daily users of marijuana had higher total testosterone levels compared to non-users.
* No associations were observed for snuff in relation to markers of testicular function.

Main message:
The study suggests that not only cigarette smoking but also use of e-cigarettes is associated with lower sperm counts. This could be important knowledge for men trying to achieve a pregnancy, as e-cigarettes are often considered to be less harmful than conventional cigarette smoking. The findings emphasize the need for more research on the potential health effects of e-cigarette use.

holmboe Sa, Priskorn L, Jensen TK, Skakkebaek NE, andersson aM, Jørgensen N. Use of e-cigarettes associated with lower sperm counts in a cross-sectional study of young men from the general population. human reproduction (Oxford, England). 2020;35(7):1693-1701. doi:10.1093/humrep/deaa089