Is smoking a risk factor for decreased semen quality? A cross-sectional analysis

Evaluation of the effects of cigarette smoking on testosterone levels in adult men

INTRODUCTION

Cigarette smoking is highly prevalent among men. Many studies have evaluated the effect of cigarette smoking on levels of male reproductive hormones; however, the findings still remain controversial.

AIM

To evaluate the influence of cigarette smoking on serum levels of total testosterone (TT), free testosterone (FT), bioavailable testosterone (BT), sex hormone-binding globulin (SHBG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH).

METHODS

A total of 255 men (90 smokers and 165 nonsmokers), aged 30 to 70 years, were investigated. Weight and height were obtained and body mass index (BMI) was calculated. Also, waist circumference and hip circumference were measured and waist-to-hip ratio was obtained. Fasting blood samples were drawn for determination of plasmatic glucose levels and serum levels of total cholesterol, high-density lipoprotein cholesterol (HDL-c), triglycerides, albumin, prolactin, TT, SHBG, LH, and FSH. The values of low-density lipoprotein cholesterol (LDL-c) were determined by Friedwald equation and the values of FT and BT were calculated from TT, SHBG, and albumin. Statistical significance was set at P < or = 0.05.

MAIN OUTCOME MEASURES

The influence of smoking on levels of TT, FT, and BT.

RESULTS

No significant difference was observed in the mean values of TT (P = 0.580), FT (P = 0.869), BT (P = 0.933), SHBG (P = 0.279), LH (P = 0.573), and FSH (P = 0.693) in the different levels of pack-years when compared to nonsmokers. Moreover, after multivariate logistic regression, no association between increased pack-years of smoking and increased odds ratio for occurrence of low hormones and SHBG levels was observed.

CONCLUSION

In this study, smokers and nonsmokers had similar mean values of androgens, gonadotropins and SHBG. However, it is necessary to standardize pack-years of smoking in order to elucidate the influence of cigarette smoking on sex hormone levels, as well as to minimize differences among studies and to confirm our results.

Cigarette smoking and reproductive function

PURPOSE OF REVIEW

To perform a systematic review of the literature on the relationship between cigarette smoking and reproductive function. Whenever possible, this review is focused on the most recently published studies (mainly the past 2 years). Nevertheless, in many instances older literature was too relevant not to be taken into account.

RECENT FINDINGS

Tobacco compounds exert a deleterious effect on the process of ovarian follicle maturation. This effect is expressed by worse in-vitro fertilization parameters in cycles performed on women with smoking habits. Also, uterine receptiveness is significantly altered by the smoking habit. In men, cigarette smoking reduces sperm production, increases oxidative stress, and DNA damage. Spermatozoa from smokers have reduced fertilizing capacity, and embryos display lower implantation rates. Even in-utero exposition to tobacco constituents leads to reduced sperm count in adult life.

SUMMARY

A strong body of evidence indicates that the negative effect of cigarette smoking on fertility comprises fairly every system involved in the reproductive process. Couples in reproductive age should be strongly discouraged to smoke.

Human exposure to endocrine disrupters and semen quality

Reproductive pathology in the male represents about 20% of infertility cases. Male infertility may be attributed to a number of causes, including genetic and congenital abnormalities, infection, multisystemic diseases, varicocele, and others; however, a significant number of cases are idiopathic. Global declines in semen quality were suggested to be associated with enhanced exposure to environmental chemicals that act as endocrine disrupters as a result of our increased use of pesticides, plastics, and other anthropogenic materials. A significant body of toxicology data based upon laboratory and wildlife animals studies suggests that exposure to certain endocrine disrupters is associated with reproductive toxicity, including (1) abnormalities of the male reproductive tract (cryptorchidism, hypospadias), (2) reduced semen quality, and (3) impaired fertility in the adult. There is, however, a relative paucity of studies designed to measure exposure to endocrine disrupters on semen quality parameters (sperm concentration, motility, morphology). An overview of the human semen quality literature is presented that examines the role of endocrine disrupters including organochlorines (OC), dioxins, phthalates, phytoestrogens, and chemical mixtures (pesticides and tobacco smoke).

Psychiatric aspects of infertility and infertility treatments

Infertility counseling, whether provided by a psychiatrist or another health care professional, involves the treatment and care of patients, not simply when they are undergoing fertility treatment but also with their long-term emotional well-being, and that of their children and the reproductive helpers who may assist them in achieving biologic or reproductive parenthood. They can educate patients about the side effects of infertility treatment medications and the impact of hormone shifts on psychologic well-being. They are also helpful with differential diagnoses among grief, depressions, and stress; in assessing psychologic preparedness; and in determining the acceptability and suitability of gamete donation, a gestational carrier, or surrogacy as a family-building alternative for individuals, couples, and reproductive collaborators.

Semen quality in a population of volunteers from the province of Barcelona

A prospective study was carried out on 1005 male volunteers residing in the province of Barcelona. Participants were asked to complete a questionnaire concerning their health status and lifestyle, and provided a semen sample for analysis. Sperm concentration and percentages of motile, and normal forms were evaluated. The effect of smoking, alcohol consumption, stress and previous disease on semen parameters was also evaluated. Normal parameters were found in 22% of volunteers and sperm counts and/or percentage motility below normal threshold values were found in 78%. Asthenozoospermia detected in 62% and oligozoospermia in 17% of volunteers. No statistically significant association was found between semen quality and age, with the exception of a decrease in semen volume (P = 0.04) and progressive motility (P = 0.01). No statistically significant differences in semen parameters were found between smokers and non-smokers or between males who consumed alcohol versus those that did not. However, stress had a negative effect on sperm concentration. In conclusion, the prevalence of normal semen parameters in the study population evaluated was markedly lower than that reported for the general population (60-70%). Since sperm concentration did not appear to decrease with age, the decrease observed in the last decades may be related to exposure to environmental toxicants during the fetal period, as previously suggested.