This study was conducted as part of an epidemiological survey of 126 nonsmokers and 178 smokers, showing primary infertility residing around Kolkata region of Eastern India. Their lifestyle history including smoking habits along with semen and blood were collected. The study examined the association of cigarette smoking with the risk of infertility, by determining the semen quality, follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone levels, and androgen receptor (AR)-CAG repeat length in a group of smokers compared with a control group (non smokers). Based on conventional WHO criteria, lower sperm motility (P < 0.001) and increased sperm morphological defects (P < 0.0001) were associated with smoking habits. Binary logistic regression analysis for the effect of smoking status on sperm DNA integrity demonstrated significant positive correlation (p = 0.006). Serum FSH and LH levels were higher for smokers compared with non-smokers while the testosterone level decreased significantly with the increasing smoking habit. The mean length of CAG repeats in AR gene was significantly higher for smokers with low testosterone compared to non-smokers. The study suggested that smoking is associated with altered semen quality, endocrine hormonal status, and number of CAG repeats in the AR gene.

Prostate specific antigen (PSA/KLK3) is known to be the chief executor of the fragmentation of semenogelins, dissolution of semen coagulum, thereby releasing sperm for active motility. Recent research has found that semenogelins also play significant roles in sperm fertility by affecting hyaluronidase activity, capacitation and motility, thereby making PSA important for sperm fertility beyond simple semen liquefaction. PSA level in semen has been shown to correlate with sperm motility, suggesting that PSA level/activity can affect fertility. However, no study investigating the genetic variations in the KLK3/PSA gene in male fertility has been undertaken. We analyzed the complete coding region of the KLK3 gene in ethnically matched 875 infertile and 290 fertile men to find if genetic variations in KLK3 correlate with infertility. Interestingly, this study identified 28 substitutions, of which 8 were novel (not available in public databases). Statistical comparison of the genotype frequencies showed that five SNPs, rs266881 (OR = 2.92, P < 0.0001), rs174776 (OR = 1.91, P < 0.0001), rs266875 (OR = 1.44, P = 0.016), rs35192866 (OR = 4.48, P = 0.025) and rs1810020 (OR = 2.08, P = 0.034) correlated with an increased risk of infertility. On the other hand, c.206 + 235 T > C, was more freuqent in the control group, showing protective association. Our findings suggest that polymorphisms in the KLK3 gene correlate with infertility risk.

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