Cannabis smoking impaired sperm quality and DNA integrity more than tobacco smoking

Comparing 37 non-smokers, 39 tobacco smokers, and 37 cannabis smokers, both tobacco and cannabis groups showed reduced normal sperm morphology and non-progressive motility. However, cannabis smokers had significantly higher rates of immotile sperm, positive acridine orange staining (indicating DNA denaturation), and positive CMA3 scores (indicating chromatin immaturity) compared to both tobacco smokers and non-smokers (P<0.001). No differences in mitochondrial cytochrome C oxidase gene variants were found between groups.

Semen samples from 113 men divided into non-smokers (n=37), tobacco smokers (n=39), and cannabis smokers (n=37). Sperm quality assessed by standard parameters. DNA integrity tested by Chromomycin A3 and acridine orange staining. Mitochondrial MT-CO1, MT-CO2, and MT-CO3 genes amplified and sequenced.

As cannabis use increases among men of reproductive age while tobacco use declines, understanding the comparative reproductive risks matters. This study found cannabis smoking produced worse sperm DNA damage than tobacco, suggesting a distinct mechanism of reproductive harm.

Male fertility has been declining globally, and understanding modifiable risk factors is critical. This study adds cannabis smoking to the list of reproductive hazards and suggests it may be more damaging to sperm DNA than tobacco, a finding relevant to fertility counseling.

Small sample sizes per group (37-39). Cross-sectional design cannot establish causation. Did not control for frequency or duration of smoking. Co-use of cannabis and tobacco was not addressed. Genetic analysis was limited to mitochondrial genes.