Introduction

To cross-sectionally assess the impact of cigarette smoking on various sperm parameters in a homogeneous cohort of white-European men presenting for primary couple infertility.

Methods

Demographic, clinical and laboratory data a cohort of primary infertile men were analyzed. Comorbidities were scored with the Charlson Comorbidity Index (CCI; categorized 0 vs. >=1). Semen analysis was based on 2010 WHO reference criteria. Serum hormones and sperm DFI [sperm chromatin structure assay (SCSA); DFI <30% was defined as non-pathologic] were measured in every patient. Smoking status was categorized as: no current smokers (Group 1); moderate smokers (<10 cigarettes/day; Group 2); and, heavy smokers (>10 cigarettes/day; Group 3). Descriptive statistics and logistic regression models tested the association between smoking status and clinical, seminal and hormonal characteristics in our cohort.

Results

Overall, 132 (69.8%), 30 (15.9%), and 27 (14.3%) patients belonged to Group 1, 2 and 3, respectively. Groups did not differ in terms of hormonal milieu. Of all, a pathologic DFI was found in 104 (55%) patients. Smokers (Groups 2+3) more frequently reported a CCI>=1 (p=0.02), oligozoospermia (p=0.04), asthenozoospermia (p=0.003), and a pathologic DFI (p=0.04) compared to non-smokers. At multiple comparison analysis, sperm concentration (p=0.042) and progressive motility (p=0.03) were significantly lower in heavy smokers; similarly, DFI values were significantly higher in Group 3 patients than in no smokers (p=0.025). At multivariable analyses, FSH (OR 1.1, p=0.02) and being heavy smokers (OR 4.1, p=0.006) were independent predictors for pathologic DFI score after accounting for age, BMI and CCI. Similarly, being heavy smokers achieved independent predictor status for pathologic sperm count (OR 2.7, p=0.047) and pathologic total progressive motility (OR 6.3, p=0.002), after accounting for the same variables.

Conclusions

The routine assessment of DFI is getting increasing clinical relevance. Heavy cigarette smoking emerged as the most detrimental factor impacting on the DFI rate, along with an impaired sperm concentration and progressive motility.

Funding

none