A new study published in Scientific Reports reveals that smoking tobacco and cannabis can damage sperm quality and DNA integrity, potentially affecting fertility. Researchers also explored whether these effects were tied to genetic changes in mitochondrial genes, but found no significant mutations.
A Growing Concern for Male Fertility
Infertility affects around 14% of couples globally, with male factors playing a role in nearly half of the cases. While tobacco use remains a widespread issue, recreational cannabis use is rising rapidly, prompting concern among health experts.
Tobacco smoke contains thousands of harmful chemicals that can damage sperm DNA. Meanwhile, tetrahydrocannabinol (THC), the psychoactive compound in cannabis, can alter sperm movement, shape, and viability. Some studies suggest THC may even change sperm epigenetics—chemical changes that affect how genes work, raising concerns about long-term effects on future generations.
Study Details
The study analyzed semen samples from 113 men, dividing them into three groups: non-smokers (NS, 37 participants), tobacco smokers (TS, 39), and cannabis smokers (CS, 37). Men with alcohol dependence, chronic illnesses, or known genetic issues were excluded.
Researchers examined standard semen parameters such as volume, sperm count, movement, and shape using World Health Organization (WHO) guidelines. They also tested sperm DNA integrity using special staining methods and examined genetic variations in three mitochondrial genes: MT-CO1, MT-CO2, and MT-CO3.
Key Findings
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Sperm Morphology: Normal sperm shape was significantly lower in both smokers’ groups, especially among cannabis users (2.26%), compared to tobacco users (5.02%) and non-smokers (7.46%).
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Motility: Cannabis users had the highest percentage of immotile sperm (68.66%), significantly higher than tobacco smokers (58.92%) and non-smokers (51.73%).
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DNA Damage: Cannabis users showed a much higher rate of sperm DNA fragmentation (28.53%) than tobacco users (6.4%) and non-smokers (10.1%). They also had higher levels of chromatin packaging defects, which can affect embryo development.
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Genetic Variations: Although the study identified several single-nucleotide polymorphisms (SNPs) in the mitochondrial genes, the differences among the three groups were not statistically significant. This suggests that the DNA damage is more likely due to epigenetic changes rather than permanent mutations.
Implications for Reproductive Health
The study concludes that both tobacco and cannabis use harm sperm quality and DNA, but cannabis may cause greater damage. Poor sperm health not only reduces the chances of conception but can also increase miscarriage risk and lead to health problems in children.
As cannabis becomes more widely accepted and legalized around the world, researchers warn of a potential reproductive health crisis. They call for more public awareness, especially among young men who may not understand the long-term risks of smoking on their fertility.
Call to Action
Health professionals and policymakers are urged to launch public education campaigns about the effects of smoking on reproductive health. Preventive efforts could help reduce infertility rates and protect the health of future generations.
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