MEN who smoke marijuana have been shown to have decreased fertility, specifically those who smoke several joints per day.
So says the results of a study, Associations between marijuana use and sperm quality in Jamaican men: Implications for the subfertile male, carried out by K Carroll et al, and shared by the Hugh Wynter Fertility Management Unit (HWFMU) at The University of the West Indies, Mona.
The objective was to evaluate the associations of frequency, quantity and duration of marijuana use with sperm parameters and reproductive histories of male non-smokers and chronic marijuana users, and to conduct the study, semen samples and marijuana consumption histories were obtained from 94 men aged 23–72 who attended the HWFMU for infertility investigations between February and September 2014.
Routine semen analyses were performed, and the associations of frequency and duration of marijuana use with sperm parameters and reproductive history were assessed.
The HWFMU shared that marijuana has been found to increase impotence, interfere with a man's ability to ejaculate, and also negatively affect sperm production, thereby reducing sperm count.
“The sperm produced by a marijuana smoking man has shown an abnormal pattern of activity. The sperm will initially become hyperactive, then run out of energy, often before they can penetrate the egg,” the unit said.
The study, published in the West Indian Medical Journal in 2017 , also outlined: “Specifically, men who reported smoking several joints/spliffs per session or smoking several times a day demonstrated poorer motility.”
Motility refers to the ability of sperm cells to 'swim' efficiently to find and penetrate the egg.
“We found that the quantity and frequency of smoking marijuana had more of an association with sperm quality than the duration for which marijuana was smoked,” the study concluded. This means that stronger strains marijuana, smoked frequently, have a more adverse effect on a man's sperm quality than the number of years he has been smoking.
The study also found that younger men who smoke marijuana are equally likely to have poor sperm motility as older men. This places the younger men at a significant disadvantage, as sperm quality is expected to decrease naturally with age.
Director of the HWFMU, Dr Vernon DaCosta, told All Woman that smoking on a whole is detrimental to fertility.
“Definitely, we would tell all men don't smoke,” he said.
“We know that smoking does have an adverse effect on semen analysis, so it would improve if they were to stop smoking. Plus, if you stop smoking there are other health benefits.”
Dr DaCosta noted, too, that there has been a global decline in fertility levels over the past half-century.
“Overall when you look at sperm quality and quantity for, say, over the last 50 years, there has been a significant decline right across the globe. This has a lot to do with food and lifestyle choices,” he said.
He recommended that in addition to quitting smoking, men should live healthy lifestyles to improve their fertility.
“In general, men should have a really balanced diet, eat a lot of fruits and vegetables, and avoid all the highly processed foods. As natural as possible is the best way to go. Exercise, and maintain a healthy body weight,” he advised.
— Candiece Knight