Endocrine Disruption as a Mediator of Declining Semen Quality in Smokers

Background: Cigarette smoking is one of the most common lifestyle and environmental risk factors for male infertility. Although smoking has been implicated in male fertility decline, the association between endocrine disruption and semen quality reduction remains underexplored in smokers. This study demonstrates the impact of reproductive hormones on the modulation of semen quality in infertile men. Methods: Eighty infertile men participated in this observational study. They were interviewed for environment and lifestyle factors, following which their semen and four reproductive hormones, viz, follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), and testosterone, were analyzed. A comparative analysis between non-smokers and smokers highlighted notable differences in hormone levels and semen quality. To explore the relationships between reproductive hormones and semen quality parameters, correlation and multiple linear regression analyses were conducted. Results: Smokers exhibited a lower percentage of live sperm (p = 0.0000) and a reduction in normal morphology. Furthermore, elevated levels of FSH, LH, and PRL were found among smokers (p = 0.0000). Notably, heightened levels of LH and PRL were linked to a decreased percentage of live sperm cells, while increased LH alone significantly impacted sperm concentration. FSH showed a negative correlation with both live sperm cells (r = −0.50) and total sperm count (r = −0.46). In contrast, testosterone levels demonstrated a positive association with normal sperm morphology (r = 0.47). Conclusion: Cigarette smoking disrupts the regulation of reproductive hormones, which further impacts semen quality. This study provides insights into the potential impact of smoking on semen quality through hormonal mechanisms.