The relationship between cannabis and male infertility, sexual health, and neoplasm: a systematic review.

BACKGROUND: In the United States of America (USA), cannabis is legal in 28 states for medical purposes and 8 states for recreational use. In 2016, the legal marijuana industry reached nearly $7 billion in sales in the USA alone. Although consumption continues to increase, the medical effects of marijuana remain understudied. Young males comprise the demographic most likely to consume cannabis, and these individuals will be most vulnerable to its short- and long-term consequences.

OBJECTIVE: The purpose of this manuscript is to systematically review the available literature describing the effects of marijuana on male infertility, sexual health, and urologic neoplasms.

MATERIALS AND METHODS: A comprehensive literature search was conducted using the Medline and Embase databases through May 2017. In vitro models, animal models, case series, case-control, and cohort designs were included. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was utilized to report results.

RESULTS: After exclusions, 91 articles were synthesized for qualitative analysis. Of these manuscripts, 30 pertained to marijuana and male infertility, 36 discussed cannabis and male sexual health/hormones, and 25 explored the relationship between marijuana and urologic neoplasms.

DISCUSSION: With respect to male factor fertility using semen parameters as a surrogate, cannabinoids likely play an inhibitory role. Data on marijuana and male sexual function are mixed but suggest that marijuana may enhance the subjective experience of sexual intercourse while potentially contributing to ED in a dose-dependent manner. Cannabis has been associated with both increased and decreased risk of malignancy depending upon the target organ. Marijuana exposure seems to be an independent risk factor for testis cancer, data on bladder cancer are conflicting, and the evidence on prostate cancer supports anti-neoplastic effects of cannabinoids.

CONCLUSION: Studies of the effects of cannabis suggest impact on urologic health and disease. Prospective, long-term studies are necessary for further elucidation of these effects.