The influence of cigarette smoking on a population of infertile men and women

Association between cigarette smoking and ovarian reserve among women seeking fertility care

INTRODUCTION

This study examined the association of smoking with ovarian reserve in a cross-sectional study of 207 women enrolled in the Louisville Tobacco Smoke Exposure, Genetic Susceptibility, and Infertility (LOUSSI) Study and assessed effect modification by NAT2 acetylator phenotype.

METHODS

Information on current smoking status was collected using a structured questionnaire and confirmed by cotinine assay. Serum anti-Müllerian hormone (AMH) levels were used to assess ovarian reserve. Diminished ovarian reserve (DOR) was defined as AMH <1ng/mL. Single nucleotide polymorphisms in the NAT2 gene, which metabolizes toxins found in cigarette smoke, were analyzed to determine NAT2 acetylator status. Linear and logistic regression were used to determine the effects of smoking on ovarian reserve and evaluate effect modification by NAT2. Regression analyses were stratified by polycystic ovary syndrome (PCOS) status and adjusted for age.

RESULTS

Current smoking status, either passive or active as measured by urinary cotinine assay, was not significantly associated with DOR. For dose-response assessed using self-report, the odds of DOR increased significantly for every additional cigarette currently smoked (Odds ratio, OR:1.08; 95% confidence interval, 95%CI:1.01-1.15); additionally, every 1 pack-year increase in lifetime exposure was associated with an increased odds of DOR among women without PCOS (OR: 1.08 95%CI: 0.99-1.18). These trends appear to be driven by the heavy or long-term smokers. Effect modification by NAT2 genotype was not established.

CONCLUSION

A history of heavy smoking may indicate increased risk of diminished ovarian reserve.

Single-nucleus RNA Sequencing reveals the mechanism of cigarette smoke exposure on diminished ovarian reserve in mice

The systematic toxicological mechanism of cigarette smoke (CS) on ovarian reserve has not been extensively investigated. Female 8-week-old C57BL/6 mice at peak fertility were exposed to CS or indoor air only for 30 days (100 mice per group) and the effects of CS on ovarian reserve were assessed using Single-Nucleus RNA Sequencing (snRNA-seq). In addition, further biochemical experiments, including immunohistochemical staining, ELISA, immunofluorescence staining, transmission electron microscopy, cell counting kit-8 assay, flow cytometry analysis, senescence-associated β-galactosidase staining, and western blotting, were accomplished to confirm the snRNA-seq results. We identified nine main cell types in adult ovaries and the cell-type-specific differentially expressed genes (DEGs) induced by CS exposure. Western blot results verified that down-regulation of antioxidant genes (Gpx1 and Wnt10b) and the steroid biosynthesis gene (Fdx1) occurred in both ovarian tissue and human granulosa cell-like tumor cell line (KGN cells) after CS exposure. Five percent cigarette smoke extract (CSE) effectively stimulated the production of reactive oxygen species (ROS), DNA damage, cellular senescence and markedly inhibited KGN cell proliferation by inducing G1-phase cell cycle arrest. Moreover, down-regulation of Gja1, Lama1 and the Ferroptosis indicator (Gpx4) in granulosa cells plays a significant role in ultrastructural changes in the ovary induced by CS exposure. These observations suggest that CS exposure impaired ovarian follicle reserve might be caused by REDOX imbalance in granulosa cells. The current study systematically determined the damage caused by CS in mouse ovaries and provides a theoretical basis for early clinical prediction, diagnosis and intervention of CS exposure-associated primary ovarian insufficiency (POI), and is of great significance in improving female reproductive health.

Smoking and obesity negatively affect the favourable outcome of varicocelectomy in sub-fertile men

We assessed the effect of smoking and/or obesity on semen parameters and testosterone/oestradiol (T/E) ratio among sub-fertile men treated with sub-inguinal varicocelectomy. In this prospective, controlled, clinical study, 80 sub-fertile men with clinical varicocele who were subjected to sub-inguinal varicocelectomy were assigned into four equal groups (n = 20/each), group A: obese and smokers, group B: obese and nonsmokers, group C: smokers and nonobese and group D: nonsmokers and nonobese. Semen parameters, serum testosterone, oestradiol, follicle-stimulating hormone, luteinising hormone, prolactin and calculation of T/E ratio were assessed at baseline and 6 months post-varicocelectomy. The mean age ± SD of the study population was 26.1 ± 4.55. No statistical difference was detected among the study groups regarding age, residence, education, marital status and occupation (p > 0.05 for each). Post-operatively, significant improvements in semen parameters were detected in all groups. There was a significant difference between groups A and B versus C and D (obese versus nonobese groups) and between groups A and C versus B and D (smokers versus nonsmokers; p < 0.05 for each) regarding semen parameters, testosterone level and T/E ratio. Smoking and/or obesity negatively affect(s) the favourable outcome of varicocelectomy, specifically improvement of semen parameters and hormonal pattern in sub-fertile men with varicocele.

Gender differences within the barriers to smoking cessation and the preferences for interventions in primary care a qualitative study using focus groups in The Hague, The Netherlands

OBJECTIVES

This research aimed to provide a deeper insight into the gender-specific barriers to smoking cessation and gender-specific preferences for interventions in primary care, in order to contribute to better aligned cessation care for women.

DESIGN

Qualitative study using focus groups.

SETTING

Regularly smoking female and male adults were recruited from four different general practices in The Hague (The Netherlands).

PARTICIPANTS

A total of 11 women and nine men participated. Participants included were regular smokers with a minimum age of 18 and sufficient command of the Dutch language, who were willing to talk about smoking cessation. Inclusion ended when saturation was reached for both women and men. Participants were selected by means of purposeful sampling, whereby looking at age, educational level and experience with quitting.

RESULTS

The main barriers to smoking cessation in women were psychological factors, such as emotion and stress, compared with environmental factors in men. Women indicated they were in need of support and positivity, and both women and men expressed the desire for assistance without judgement. Contrary to men, women were not drawn to restrictions and (dis)incentives.

CONCLUSION

When counselling smokers, in women the focus should be on perceived internal problems, as opposed to more external obstacles in men. Contrary to men, female smokers seem to prefer non-coercive interventions, such as a group intervention offering support and positivity. Future research should focus on these gender differences, and how they could improve treatment in primary care.

Demographic and evolutionary trends in ovarian function and aging

BACKGROUND

The human female reproductive lifespan is regulated by the dynamics of ovarian function, which in turn is influenced by several factors: from the basic molecular biological mechanisms governing folliculogenesis, to environmental and lifestyle factors affecting the ovarian reserve between conception and menopause. From a broader point of view, global and regional demographic trends play an additional important role in shaping the female reproductive lifespan, and finally, influences on an evolutionary scale have led to the reproductive senescence that precedes somatic senescence in humans.

OBJECTIVE AND RATIONALE

The narrative review covers reproductive medicine, by integrating the molecular mechanisms of ovarian function and aging with short-term demographic and long-term evolutionary trends.

SEARCH METHODS

PubMed and Google Scholar searches were performed with relevant keywords (menopause, folliculogenesis, reproductive aging, reproductive lifespan and life history theory). The reviewed articles and their references were restricted to those written in English.

OUTCOMES

We discuss and summarize the rapidly accumulating information from large-scale population-based and single-reproductive-cell genomic studies, their constraints and advantages in the context of female reproductive aging as well as their possible evolutionary significance on the life history trajectory from foetal-stage folliculogenesis until cessation of ovarian function in menopause. The relevant environmental and lifestyle factors and demographic trends are also discussed in the framework of predominant evolutionary hypotheses explaining the origin and maintenance of menopause.

WIDER IMPLICATIONS

The high speed at which new data are generated has so far raised more questions than it has provided solid answers and has been paralleled by a lack of satisfactory interpretations of the findings in the context of human life history theory. Therefore, the recent flood of data could offer an unprecedented tool for future research to possibly confirm or rewrite human evolutionary reproductive history, at the same time providing novel grounds for patient counselling and family planning strategies.

The current status and future of andrology: A consensus report from the Cairo workshop group

BACKGROUND

In attempting to formulate potential WHO guidelines for the diagnosis of male infertility, the Evidence Synthesis Group noted a paucity of high-quality data on which to base key recommendations. As a result, a number of authors suggested that key areas of research/evidence gaps should be identified, so that appropriate funding and policy actions could be undertaken to help address key questions.

OBJECTIVES

The overall objective of this Consensus workshop was to clarify current knowledge and deficits in clinical laboratory andrology, so that clear paths for future development could be navigated.

MATERIALS AND METHODS

Following a detailed literature review, each author, prior to the face-to-face meeting, prepared a summary of their topic and submitted a PowerPoint presentation. The topics covered were (a) Diagnostic testing in male fertility and infertility, (b) Male fertility/infertility in the modern world, (c) Clinical management of male infertility, and (d) The overuse of ICSI. At the meeting in Cairo on February 18, 2019, the evidence was presented and discussed and a series of consensus points agreed.

RESULTS

The paper presents a background and summary of the evidence relating to these four topics and addresses key points of significance. Following discussion of the evidence, a total of 36 consensus points were agreed.

DISCUSSION

The Discussion section presents areas where there was further debate and key areas that were highlighted during the day.

CONCLUSION

The consensus points provide clear statements of evidence gaps and/or potential future research areas/topics. Appropriate funding streams addressing these can be prioritized and consequently, in the short and medium term, answers provided. By using this strategic approach, andrology can make the rapid progress necessary to address key scientific, clinical, and societal challenges that face our discipline now and in the near future.

Tobacco smoking and semen quality in infertile males: a systematic review and meta-analysis

BACKGROUND

Nowadays, the total number of couples visiting an infertility clinic is on the rise. Tobacco smoking is considered one of the major factors leading to male infertility. In this study, we aimed to systematically investigate the impact of tobacco smoking on semen quality in infertile male participants.

METHODS

Online databases (Cochrane Central database of Randomized Controlled Trials and the databases of MEDLINE and EMBASE respectively) were searched for relevant English publications that satisfied the inclusion and exclusion criteria of this analysis. The clinical endpoints which were assessed included semen parameters (oligozoospermia, asthenozoospermia, teratozoospermia, and azoospermia), morphological defects of spermatozoa and the hormones involved in reproduction. RevMan 5.3 software was used to analyze the data whereby mean difference (MD) and risk ratios (RR) with 95% confidence intervals (CI) were generated to represent the results.

RESULTS

Sixteen studies with a total number of 10,823 infertile male participants (5257 smokers and 5566 non-smokers) were included. Results of this analysis showed oligozoospermia to be significantly higher in smokers (RR: 1.29, 95% CI: 1.05-1.59; P = 0.02). Morphological defect of spermatozoa (MD: 2.44, 95% CI: 0.99-3.89; P = 0.001) was also significantly higher in smokers whereby significant head (MD: 1.76, 95% CI: 0.32-3.20; P = 0.02), neck (MD: 1.97, 95% CI: 0.75-3.18; P = 0.002) and tail (MD: 1.29, 95% CI: 0.35-2.22; P = 0.007) defects were observed. However, smoking did not affected the pH (MD: 0.04, 95% CI: [- 0.03-0.11]; P = 0.30) and motility (RR: 1.42, 95% CI: 0.97-2.09; P = 0.07) of spermatozoa. Additionally, tobacco smoking did not cause any dis-balance in hormones which were involved in reproduction.

CONCLUSIONS

In conclusion, with reference to the clinical endpoints which were studied in this analysis, tobacco smoking was associated with a lower sperm count and an increase in the number of morphological defects of spermatozoa. However, the pH and motility of spermatozoa as well as the production of hormones which were involved in reproduction were not affected in this population of infertile males.

Infertility in the Moroccan population: major risk factors encountered in the reproductive health centre in Rabat

Infertility is responsible for a major cost burden for patients and health care systems. Therefore identifying preventable risk factors for infertility may contribute to the development of more cost-effective approaches to solving the infertility problem. However, such investigations have never been conducted in Morocco. Thereby, the objective of the present study was to determine the occurrence and distribution of these factors among Moroccan infertile couples. This retrospective study included 1265 infertile couples who attended the Assisted Reproductive Technology Unit of the Reproductive Health Centre of the University Hospital Ibn Sina in Rabat. All couples had been infertile for at least 1 year and both partners were fully investigated. Couples had primary and secondary infertility in 77.2% and 22.8% of cases, respectively. Women were overweight in 47.9% of cases and obese in 25.8% of cases while men were overweight in 44.6% of cases and obese in 14.7% of cases. 18.9% of women and 17.5% of men had a previous abdominopelvic or urogenital surgery. A history of sexually transmitted infection was reported by 7% of men and 5.8% of women. A history of tuberculosis was found 9.3% of women and 4.8% of men. In addition, 31.7% of men were cigarette smokers and 8.4% consumed alcohol. The study showed that preventable risk factors of infertility are common among Moroccan infertile couples. However, additional studies are required to investigate each factor and its relation to infertility in the Moroccan population.

Paternal smoking and spontaneous abortion: a population-based retrospective cohort study among non-smoking women aged 20-49 years in rural China

BACKGROUND

To comprehensively evaluate the association of paternal smoking and spontaneous abortion.

METHODS

We conducted a population-based retrospective cohort study among 5 770 691 non-smoking rural Chinese women, along with their husbands, participating in the National Free Pre-Pregnancy Checkups Project, regarding outcome events that occurred in 2010-2016. The main outcome was spontaneous abortion (SA). Multivariable logistic regression was used to estimate OR and 95% CI, and restricted cubic spline was used to estimate the non-linear relationship.

RESULTS

The multivariable-adjusted OR of exposure to paternal smoking for SA was 1.17 (95% CI 1.16 to 1.19), compared with women without exposure to paternal smoking; and corresponding OR of exposure to preconception paternal smoking for SA was 1.11 (95% CI 1.08 to 1.14), compared with women without exposure to preconception paternal smoking. The ORs of preconception paternal smoking also increased with increases in paternal smoking (p_nonlinear<0.05, almost linearly shaped) and preconception paternal smoking (p_nonlinear>0.05). In addition, periconception paternal smoking cessation was associated with an 18% (15%-22%) lower risk of SA.

CONCLUSION

Paternal smoking was associated with SA. The importance of tobacco control, specifically pertaining to paternal smoking, should be emphasised during preconception and pregnancy counselling.

Couple's infertility in relation to male smoking in a Chinese rural area

Smoking is a well-known risk factor of reproductive health. However, the effect of paternal smoking on fertility has been less extensively examined. We conducted a cross-sectional study in a mountainous area of South-West China to assess the effect of male smoking on couples’ fertility. A total of 8200 couples aged 18–49 years in the study area were invited to participate in the study. An in-person interview was performed to collect demographic characteristics of the couples, and husbands’ life style factors including smoking and drinking habits. Information on time to pregnancy (TTP) was collected retrospectively. Infertility was defined as failure to achieve clinical pregnancy after regular unprotected intercourse for ≥12 months. Logistic regression model was used to estimate the association between male smoking and infertility. A total of 7025 couples were included in the final analysis. After adjusting for potential confounders, the couples were more likely to suffer from infertility if the husbands smoked (adjusted odds ratio [aOR] =1.28, 95% CI: 1.08–1.52) before the first pregnancy. After the analyses were performed according to husbands’ smoking duration, an increased risk started at a relatively longer smoking duration of 5–10 years (aOR = 1.58, 95% CI: 1.26–1.99) and a stronger association (aOR = 3.34, 95% CI: 2.45–4.56) was observed in the group of ≥10 years. Similar patterns were found for the number of cigarettes smoked per day and the total amount of cigarettes smoked. From our findings, we conclude that male smoking may have an adverse impact on couples’ infertility.

Androgen Receptor Genotype in Humans and Susceptibility to Endocrine Disruptors

Although animal studies have raised concern that the influence of endocrine-disrupting compounds would obstruct the development of the male reproductive system, in general, exposure levels far above those found in humans have been needed to induce reproductive toxicity in animal models. Human data are inconclusive and have evoked the question whether endocrine-disrupting compounds can have any impact on hormonal function and thus health consequences when natural hormones are present. Indeed, many contaminants with hormone-like activity are much less potent than endogenous hormones themselves: 17β-oestradiol was, for instance, estimated to be 17,000 times more potent than o,p'-DDT. However, humans are exposed to a multitude of agents, and when present in sufficient number and concentration, they might in principle act collected on the actions of endogenous hormones. Whether such effects will be physiologically relevant is still not known. Nevertheless, in the worst-case scenario, there are no threshold levels below which there are no effects at all, and one target molecule is the androgen receptor. This mini review focuses on the androgen receptor gene, its link with classical endocrine disruptors and smoking, and how common genetic variants in the androgen receptor gene may influence physiological outcomes.

Associations of Demographic Factors and Tobacco Use With Progesterone and Estradiol During Pregnancy

OBJECTIVE

To evaluate the association of biochemically validated prenatal tobacco use with serum progesterone and estradiol in the second trimester of pregnancy, controlling for demographic and personal factors.

STUDY DESIGN

This secondary analysis of a multicenter longitudinal study included 114 women with singleton pregnancies. Multiple regression analysis assessed whether prenatal tobacco use was related to hormone levels during the second trimester, controlling for covariates (age, body mass index, and race or ethnicity, with gestational age added to subsequent models).

RESULT

In the initial regressions, tobacco users had significantly lower progesterone level compared with nonsmokers (p = .037), while estradiol was unrelated to prenatal tobacco use. Women with greater body mass index also had significantly lower progesterone (p = .028), but body mass index was unrelated to estradiol. With gestational age as an additional covariate, prenatal tobacco use was no longer a significant predictor of progesterone, but both body mass index and gestational age were significant (F = 10.6, p < .001, R 2 = 0.35). For estradiol, the overall regression of estradiol on age, body mass index, and race or ethnicity was not significant (F = 1.2, p = .31). With gestational age added to the model, the overall model was significant (F = 7.2, p < .001, R 2 = 0.27).

CONCLUSION

This study provides additional evidence that prenatal tobacco use may influence lower serum progesterone during the second trimester. This is of particular concern given the link between depressed progesterone activity and risk for preterm birth.

The diagnosis of male infertility: an analysis of the evidence to support the development of global WHO guidance-challenges and future research opportunities

BACKGROUND

Herein, we describe the consensus guideline methodology, summarize the evidence-based recommendations we provided to the World Health Organization (WHO) for their consideration in the development of global guidance and present a narrative review of the diagnosis of male infertility as related to the eight prioritized (problem or population (P), intervention (I), comparison (C) and outcome(s) (O) (PICO)) questions. Additionally, we discuss the challenges and research gaps identified during the synthesis of this evidence.

OBJECTIVE AND RATIONALE

The aim of this paper is to present an evidence-based approach for the diagnosis of male infertility as related to the eight prioritized PICO questions.

SEARCH METHODS

Collating the evidence to support providing recommendations involved a collaborative process as developed by WHO, namely: identification of priority questions and critical outcomes; retrieval of up-to-date evidence and existing guidelines; assessment and synthesis of the evidence; and the formulation of draft recommendations to be used for reaching consensus with a wide range of global stakeholders. For each draft recommendation the quality of the supporting evidence was then graded and assessed for consideration during a WHO consensus.

OUTCOMES

Evidence was synthesized and recommendations were drafted to address the diagnosis of male infertility specifically encompassing the following: What is the prevalence of male infertility and what proportion of infertility is attributable to the male? Is it necessary for all infertile men to undergo a thorough evaluation? What is the clinical (ART/non ART) value of traditional semen parameters? What key male lifestyle factors impact on fertility (focusing on obesity, heat and tobacco smoking)? Do supplementary oral antioxidants or herbal therapies significantly influence fertility outcomes for infertile men? What are the evidence-based criteria for genetic screening of infertile men? How does a history of neoplasia and related treatments in the male impact on (his and his partner's) reproductive health and fertility options? And lastly, what is the impact of varicocele on male fertility and does correction of varicocele improve semen parameters and/or fertility?

WIDER IMPLICATIONS

This evidence synthesis analysis has been conducted in a manner to be considered for global applicability for the diagnosis of male infertility.

From sperm to offspring: Assessing the heritable genetic consequences of paternal smoking and potential public health impacts

Individuals who smoke generally do so with the knowledge of potential consequences to their own health. What is rarely considered are the effects of smoking on their future children. The objective of this work was to review the scientific literature on the effects of paternal smoking on sperm and assess the consequences to offspring. A literature search identified over 200 studies with relevant data in humans and animal models. The available data were reviewed to assess the weight of evidence that tobacco smoke is a human germ cell mutagen and estimate effect sizes. These results were used to model the potential increase in genetic disease burden in offspring caused by paternal smoking, with specific focus on aneuploid syndromes and intellectual disability, and the socioeconomic impacts of such an effect. The review revealed strong evidence that tobacco smoking is associated with impaired male fertility, and increases in DNA damage, aneuploidies, and mutations in sperm. Studies support that these effects are heritable and adversely impact the offspring. Our model estimates that, with even a modest 25% increase in sperm mutation frequency caused by smoke-exposure, for each generation across the global population there will be millions of smoking-induced de novo mutations transmitted from fathers to offspring. Furthermore, paternal smoking is estimated to contribute to 1.3 million extra cases of aneuploid pregnancies per generation. Thus, the available evidence makes a compelling case that tobacco smoke is a human germ cell mutagen with serious public health and socio-economic implications. Increased public education should be encouraged to promote abstinence from smoking, well in advance of reproduction, to minimize the transmission of harmful mutations to the next-generation.

Environmental pollutants, a possible etiology for premature ovarian insufficiency: a narrative review of animal and human data

BACKGROUND

Because only 25% of cases of premature ovarian insufficiency (POI) have a known etiology, the aim of this review was to summarize the associations and mechanisms of the impact of the environment on this pathology. Eligible studies were selected from an electronic literature search from the PUBMED database from January 2000 to February 2016 and associated references in published studies. Search terms included ovary, follicle, oocyte, endocrine disruptor, environmental exposure, occupational exposure, environmental contaminant, pesticide, polyaromatic hydrocarbon, polychlorinated biphenyl PCB, phenol, bisphenol, flame retardant, phthalate, dioxin, phytoestrogen, tobacco, smoke, cigarette, cosmetic, xenobiotic. The literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We have included the human and animal studies corresponding to the terms and published in English. We have excluded articles that included results that did not concern ovarian pathology and those focused on ovarian cancer, polycystic ovary syndrome, endometriosis or precocious puberty. We have also excluded genetic, auto-immune or iatrogenic causes from our analysis. Finally, we have excluded animal data that does not concern mammals and studies based on results from in vitro culture. Data have been grouped according to the studied pollutants in order to synthetize their impact on follicular development and follicular atresia and the molecular pathways involved. Ninety-seven studies appeared to be eligible and were included in the present study, even though few directly address POI. Phthalates, bisphenol A, pesticides and tobacco were the most reported substances having a negative impact on ovarian function with an increased follicular depletion leading to an earlier age of menopause onset. These effects were found when exposure occured at different times throughout the lifetime from the prenatal to the adult period, possibly due to different mechanisms. The main mechanism seemed to be an increase in atresia of pre-antral follicles.

CONCLUSION

Environmental pollutants are probably a cause of POI. Health officials and the general public must be aware of this environmental effect in order to implement individual and global preventive actions.

Endocrine Disrupting Chemicals and Endometrial Cancer: An Overview of Recent Laboratory Evidence and Epidemiological Studies

Background: Although exposure to endocrine disruptor compounds (EDCs) has been suggested as a contributing factor to a range of women's health disorders including infertility, polycystic ovaries and the early onset of puberty, considerable challenges remain in attributing cause and effect on gynaecological cancer. Until recently, there were relatively few epidemiological studies examining the relationship between EDCs and endometrial cancer, however, in the last years the number of these studies has increased. Methods: A systematic MEDLINE (PubMed) search was performed and relevant articles published in the last 23 years (from 1992 to 2016) were selected. Results: Human studies and animal experiments are confirming a carcinogenic effect due to the EDC exposure and its carcinogenesis process result to be complex, multifactorial and long standing, thus, it is extremely difficult to obtain the epidemiological proof of a carcinogenic effect of EDCs for the high number of confusing factors. Conclusions: The carcinogenic effects of endocrine disruptors are plausible, although additional studies are needed to clarify their mechanisms and responsible entities. Neverthless, to reduce endocrine disruptors (ED) exposure is mandatory to implement necessary measures to limit exposure, particularly during those periods of life most vulnerable to the impact of oncogenic environmental causes, such as embryonic period and puberty.

Discrete survival model analysis of a couple's smoking pattern and outcomes of assisted reproduction

Background

Cigarette smoking has been associated with worse infertility treatment outcomes, yet some studies have found null or inconsistent results.

Methods

We followed 225 couples who underwent 354 fresh non-donor assisted reproductive technology (ART) cycles between 2006 and 2014. Smoking history was self-reported at study entry. We evaluated the associations between smoking patterns and ART success using multivariable discrete time Cox proportional hazards models with six time periods: cycle initiation to egg retrieval, retrieval to fertilization, fertilization to embryo transfer (ET), ET to implantation, implantation to clinical pregnancy, and clinical pregnancy to live birth to estimate hazard ratios (HR) and 95% CIs. Time-dependent interactions between smoking intensity and ART time period were used to identify vulnerable periods.

Results

Overall, 26% of women and 32% of men reported ever smoking. The HR of failing in the ART cycle without attaining live birth for male and female ever smokers was elevated, but non-significant, compared to never smokers regardless of intensity (HR = 1.02 and 1.30, respectively). Female ever smokers were more likely to fail prior to oocyte retrieval (HR: 3.37; 95% CI: 1.00, 12.73). Every one cigarette/day increase in smoking intensity for females was associated with a HR of 1.02 of failing ART (95% CI: 0.97, 1.08), regardless of duration or current smoking status. Women with higher smoking intensities were most likely to fail a cycle prior to oocyte retrieval (HR: 1.07; 95% CI: 1.00, 1.16). Among past smokers, every additional year since a man had quit smoking reduced the risk of failing ART by 4% (HR: 0.96; 95% CI: 0.91, 1.00) particularly between clinical pregnancy and live birth (HR: 0.86; 95% CI: 0.76, 0.96).

Conclusions

Female smoking intensity, regardless of current smoking status, is positively associated with the risk of failing ART cycles between initiation and oocyte retrieval. In men who ever smoked, smoking cessation may reduce the probability of failing ART, particularly between clinical pregnancy and live birth.

Trial registration

NCT00011713. Registered: 27 February 2001.

Electronic supplementary material

The online version of this article (doi:10.1186/s40738-017-0032-2) contains supplementary material, which is available to authorized users.

Major Disease Prevalence and Menstrual Characteristics in Infertile Female Korean Smokers

We investigated the prevalence of smoking and factors associated with smoking in infertile Korean women. Smoking status, education, occupation, personal habits, past medical history, current illness, stress level, and menstrual characteristics were collected from self-report questionnaires. The Beck Depression Inventory (BDI) was used to assess the degree of depression. Data on the causes of infertility and levels of six reproductive hormones were collected from medical records. Among 785 women less than 42 years of age, the prevalence of current, secondhand, past, and never smokers were 12.7%, 45.7%, 0.9%, and 40.6%, respectively. Primary infertility was more frequent in secondhand smokers. Causes of infertility were similar among current, secondhand, and never smokers. Current smokers were less educated (P < 0.001) and more likely to consume alcohol than secondhand or never smokers (P < 0.001). Secondhand smokers slept less than current smokers (P = 0.041). Among several major diseases, only the prevalence of diabetes mellitus (4.0%) was significantly higher in current smokers than in secondhand smokers (0.0%, P = 0.002) or never smokers (0.6%, P = 0.031). The self-reported prevalence of depression, and the degree of depression were similar among women with different smoking statuses. There were no differences in menstrual characteristics or serum levels of six reproductive hormones between current, secondhand, and never smokers, even after excluding women with polycystic ovary syndrome. In conclusion, education/employment status, alcohol drinking, and the prevalence of primary infertility and diabetes mellitus were significantly different according to smoking status among infertile women.

Impact of smoking on fertility and age of menopause: a population-based assessment

BACKGROUND AND AIMS

Studies in patients seeking medically assisted reproduction have shown that smoking reduces fertility, but little information is available in the general population. We assessed the associations between smoking and the number of children, childbearing planning and age at menopause in a representative sample of the population of Lausanne, Switzerland.

METHODS

Data from 6711 participants (3530 women, age range 35-75 years) collected between 2003 and 2006 and again in 2009 and 2012. Smoking status, number of offsprings and age of menopause were assessed.

RESULTS

Women who currently smoke had significantly less children than former or never smokers: the number of children per women (average±SD) was 1.38±1.05, 1.45±1.07 and 1.576±1.16, respectively (p<0.001). Women who currently smoke had their first child at an earlier age than the others: 26.7±5.2, 27.4±5.4 and 26.9±5.2 years old for current, former and never smokers, respectively, (p=0.01). Similar findings were found for men: number of children per men 1.475±1.16, 1.67±1.13 and 1.55±1.22 for current, former and never smokers, respectively (p<0.001); no difference was found regarding age at the first child. The difference persisted after multivariate adjustment (adjusted for age, body mass index, Caucasian origins, alcohol consumption, caffeinated drinks consumption, educational level, receiving social help and women taking contraceptives) for the age at first child among women. No association was found between Heaviness of Smoking Index and the number of children among current smokers in both genders. Women who smoke had their menopause more than 1 year prior than never-smoking women (48.9±0.2 years compared with 47.8±0.3 years, respectively, p=0.002).

CONCLUSIONS

Smoking is associated with an earlier age of having the first child and of menopause among women.

Cigarette Smoking and Semen Quality: A New Meta-analysis Examining the Effect of the 2010 World Health Organization Laboratory Methods for the Examination of Human Semen

OBJECTIVE

Approximately 37% of men of reproductive age smoke cigarettes, with Europe having the highest tobacco use among all the World Health Organization (WHO) regions. Toxins from tobacco smoking can potentially affect sperm development and function, with a negative effect on semen parameters. Given the high prevalence of smoking and recent changes in the WHO laboratory methods for the examination of human semen, the role of this exposure in face of new WHO methods needs to be clarified.

EVIDENCE ACQUISITION

We conducted a systematic review, followed by a meta-analysis, to determine whether cigarette smoking affects human semen parameters. PubMed, Saint Joseph's University Discover, and Google Scholar were used to identify relevant studies published after release of the latest WHO methods for laboratory evaluation of human semen. Participants were from fertility/urologic clinics and andrology laboratories. The outcome measures were semen volume, sperm concentration, motility, and morphology, the parameters usually used in clinical settings to assess fertility.

EVIDENCE SYNTHESIS

Twenty studies with 5865 participants were included in the meta-analysis. Exposure to cigarette smoking was associated with reduced sperm count (mean difference [MD]: -9.72×10⁶/ml; 95% confidence interval [CI], -13.32 to -6.12), motility (MD: -3.48%; 95% CI, -5.53 to -1.44), and morphology (MD: -1.37%; 95% CI, -2.63 to -0.11). Subgroup analyses indicated that effect size was higher in infertile men than in the general population and in moderate/heavy smokers than in mild smokers. The overall effect size on semen volume, sperm count, and motility remained similar when 2010 and earlier WHO manuals were used for semen analysis but was lower with regard to sperm morphology.

CONCLUSIONS

Our results suggest that cigarette smoking has an overall negative effect on semen parameters. The latest WHO laboratory methods for the examination of human semen had a minimal impact on the magnitude of effect size, thus confirming the observed negative effect of smoking on conventional semen parameters.

PATIENT SUMMARY

A new systematic review and meta-analysis comprising 5865 men shows that cigarette smoking is associated with reduced sperm count and motility. Deterioration of semen quality is more pronounced in moderate and heavy smokers.

Association between some inflammatory markers and primary ovarian insufficiency

OBJECTIVE

This study investigated the discriminative values of neutrophil-to-lymphocyte ratio (NLR), serum amyloid A protein (SAA), and C-reactive protein (CRP) in cases of primary ovarian insufficiency (POI).

METHODS

A total of 84 women were included in this comparative cross-sectional study. The study group consisted of 43 women diagnosed as having POI, and the control group consisted of 41 women with normal fertility. After obtaining a written informed consent form from all participants, we retrieved clinical and demographic data and laboratory findings from the participants and the hospital database. The following variables were analyzed: age, body mass index, smoking, family history, comorbidities, sonographic findings, complete blood count, baseline hormone levels, CRP, and SAA.

RESULTS

NLR was significantly lower in the study group than in the control group (mean [SD], 1.3 [0.7] vs 2.0 [0.7]; P < 0.001). The mean SAA level was 151.6 ng/mL (range, 48.5-12,554.7 ng/mL) in the study group and 147.8 ng/mL (range, 29.8-3,760.4 ng/mL) in the control group (P > 0.05). There was no significant difference in serum CRP levels between two groups (P > 0.05). Receiver operating characteristic analysis revealed that NLR, but not SAA and CRP, was a significantly discriminative parameter for POI (area under the curve, 0.829; P < 0.001). Multivariate logistic regression analysis showed that a family history of POI, smoking, and NLR of 1.5 or less were independent risk factors for POI.

CONCLUSIONS

SAA and CRP do not seem to be valuable discriminative markers for POI, whereas NLR may be a significant promising marker before presentation or in the early stages of POI and may be useful for developing appropriate fertility treatment options.

The amount and duration of smoking is associated with aggravation of hormone and biochemical profile in women with PCOS

We investigated the association between the amount and duration of smoking on biochemical, clinical parameters and the ovarian morphology in women with polycystic ovary syndrome (PCOS). That was a retrospective study. These women were divided into two groups, non-smokers (217) and smokers (92). The amount of cigarettes and duration of smoking was measured in pack-years. Both groups underwent clinical evaluation, biochemical and hormone analysis, transvaginal ultrasound and oral glucose tolerance tests (OGTT). The mean value of the number of cigarettes was 14.8 (±8.8) and the median value of pack-years in the smokers group was 4.0 (1.5-7.5). Smokers group has significantly higher free testosterone (F-T), 17-hydroxyprogesterone (17-OHP), delta 4 androstenedione (Δ4-A), T4, low-density lipoprotein (LDL), and white blood cells (WBC). During correlation of all the above parameters and pack-years, there has been significant positive correlation in F-T and Δ4-A. The participants with more pack-years showed statistically higher values of F-T and Δ4-A. There was also a significant positive correlation between total cholesterol, triglycerides, WBC and pack-years of the participants. Prolactin (PRL) has been inversely associated with pack-years. We concluded that the increase of pack-years aggravated lipid profile, WBC and decreased PRL levels, in PCOS patients.

Clinical, demographic and psychological characteristics of infertile male smokers in Northeast China

Objectives

To investigate clinical, demographic and psychological characteristics of infertile male smokers in northeast China.

Methods

Serum and semen samples were collected from infertile men. Semen analysis was performed according to conventional procedures. Serum follicle-stimulating hormone, luteinizing hormone and testosterone levels were quantified. Psychological anxiety and depression were evaluated by the self-rating anxiety scale (SAS) and self-rating depression scale (SDS), respectively.

Results

Both SDS and SAS scores were significantly higher in smokers (n = 704) than in nonsmokers (n = 372); in addition, sperm viability and motility were significantly lower in smokers than in nonsmokers. Spearman’s correlation coefficient analysis revealed significant positive correlations between duration of smoking and SDS and SAS scores, and between cigarettes smoked per day and SDS and SAS scores.

Conclusions

Cigarette smoking has a negative effect on sperm viability and motility, and is associated with increased SDS and SAS scores.

The Bologna criteria for poor ovarian response: a contemporary critical appraisal

Postponement of child bearing and maternal age at first pregnancy are on the rise, contributing considerably to an increase in age-related infertility and the demand for assisted reproductive technologies (ART) treatment. This brings to the infertility clinics many women with low ovarian reserve and poor ovarian response (POR) to conventional stimulation. The Bologna criteria were released to standardize the definition of POR and pave the way for the formulation of evidence-based, efficient modalities of treatment for women undergoing IVF-ET. More than four years have passed since the introduction of these criteria and the debate is still ongoing whether a revision is due. Women with POR comprise several sub-groups with diverse baseline distinctiveness, a major issue that has fueled the discussion. Although antral follicle count (AFC) and anti-Müllerian hormone (AMH), are considered good predictors of ovarian reserve, their threshold values are still not universally standardized. Different definitions for sonographic AFC and diverse assays for AMH are held responsible for this delay in standardization. Adding established risk factors to the criteria will lead to more reliable and reproducible definition of a POR, especially in young women. The original criteria did not address the issue of oocyte quality, and the addition of risk factors may yield specific associations with quality vs. quantity. Patient’s age is the best available criterion, although limited, to predict live-birth and presumably oocyte quality. High scale studies to validate these criteria are still missing while recent evidence raises concern regarding over diagnosis.

Systematic and meta-analytic review of research examining the impact of menstrual cycle phase and ovarian hormones on smoking and cessation

INTRODUCTION

To determine the effect of ovarian hormones on smoking, we conducted a systematic review of menstrual cycle effects on smoking (i.e., ad lib smoking, smoking topography, and subjective effects) and cessation-related behaviors (i.e., cessation, withdrawal, tonic craving, and cue-induced craving).

METHODS

Thirty-six papers were identified on MEDLINE that included a menstrual-related search term (e.g., menstrual cycle, ovarian hormones), a smoking-related search term (e.g., smoking, nicotine), and met all inclusion criteria. Thirty-two studies examined menstrual phase, 1 study measured hormone levels, and 3 studies administered progesterone.

RESULTS

Sufficient data were available to conduct meta-analyses for only 2 of the 7 variables: withdrawal and tonic craving. Women reported greater withdrawal during the luteal phase than during the follicular phase, and there was a nonsignificant trend for greater tonic craving in the luteal phase. Progesterone administration was associated with decreased positive and increased negative subjective effects of nicotine. Studies of menstrual phase effects on the other outcome variables were either small in number or yielded mixed outcomes.

CONCLUSIONS

The impact of menstrual cycle phase on smoking behavior and cessation is complicated, and insufficient research is available upon which to conduct meta-analyses on most smoking outcomes. Future progress will require collecting ovarian hormone levels to more precisely quantify the impact of dynamic changes in hormone levels through the cycle on smoking behavior. Clarifying the relationship between hormones and smoking-particularly related to quitting, relapse, and medication response-could determine the best type and timing of interventions to improve quit rates for women.

Effect of smoking on reproductive hormones and semen parameters of infertile Saudi Arabians

OBJECTIVE

The purpose of this retrospective study is to look into the effect of smoking on semen and hormonal profile of Saudi Arabians attending infertility clinics.

MATERIALS AND METHODS

Medical record numbers of patients who attended infertility clinics and who underwent full assessment were identified rom Quadramed system and out-patient log books between January 2010 and December 2012. The standard protocol of the patients include full history, age, number of years of marriage personal habits of smoking, alcohol consumption, primary or secondary infertility. Standard laboratory tests which were performed, included, complete blood picture, random blood sugar, testosterone, follicle stimulation hormone, luteinizing hormone, prolactin level and semen analysis; volume, count, progressive motility and morphology. The data was entered in the database and analyzed.

RESULTS

During the study period, 279 patients attended and infertility clinic and only 258 gave the sample for analysis. The average age of patients in the smoking group was 34.23 ± 7.66 and in the nonsmokers 34.07 ± 7.92 years. Primary infertility was more common in smokers versus nonsmokers P < 0.001 confidence interval (CI)< -44.0705, total serum testosterone level was lower 383.8 ± 239.5 versus 422.5 ± 139.2 ng/dL (0.009 CI< -9.9415), serum prolactin level was higher 18.68 ± 13.28 versus 12.85 ± 12.34 ng/mL (0.001 CI < 8.3794). The average volume of the semen among the smokers was 2.8 ± 1.35 mL and in nonsmokers it was 3.08 ± 0.76 mL (P < 0.008 CI< -0.123). The mean progressive motility in smokers was 31.5 ± 23.1 compared to nonsmokers 40.05 ± 25.43% (0.002 CI< -3.2962) and total sperm count was 119.52 ± 114.12 and 139.71 ± 104.82 million/mL (0.07 CI < 1.4657).

CONCLUSIONS

This study shows that the effect of smoking is dramatic reduction in the hormonal levels and semen parameters. It is recommended that smoking men undergoing fertility treatment should stop smoking to increase their chances of having offspring.

Sexual orientation of women does not affect outcome of fertility treatment with donated sperm

STUDY QUESTION

Is there a difference in fertility between heterosexual women and lesbians undergoing sperm donation?

SUMMARY ANSWER

Women undergoing treatment with donated sperm are equally fertile regardless of sexual orientation.

WHAT IS KNOWN ALREADY

Lesbians have an increased prevalence of smoking, obesity, sexually transmitted diseases and, possibly, polycystic ovary syndrome, all factors known to affect fertility. Previous studies on sperm donation inseminations (D-IUI) show conflicting results regarding pregnancy outcome.

STUDY DESIGN, SIZE, DURATION

This is a national study of 171 lesbians and 124 heterosexual women undergoing sperm donation both as D-IUI (lesbian n = 438, heterosexual n = 298) and as embryo transfers (ET) after IVF with donated sperm (lesbians n = 225, heterosexuals n = 230) during 2005-2010.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All clinics in Sweden offering sperm donation recruited patients. Differences in patients' medical history, treatment results and number of treatments to live birth were analyzed using independent samples t-test, Pearson's χ(2) test or Fisher's exact probability test.

MAIN RESULTS AND THE ROLE OF CHANCE

71.8% of heterosexuals and 69.0% of lesbians had a child after treatment. The mean number of treatments was 4.2 for heterosexual women and 3.9 for lesbians. The total live birth rate, regardless of treatment type, was 19.7% for heterosexuals and 19.5% for lesbians. For D-IUI, the live birth rate was 12.8% for heterosexuals and 16.0% for lesbians and the live birth rate for all IVF embryo transfers (fresh and thawed cycles) was 28.7% for heterosexuals and 26.2% for lesbians. There were no differences in live birth rate between the groups for each of the different types of insemination stimulations (natural cycle; clomiphene citrate; FSH; clomiphene citrate and FSH combined). Nor was there a difference in live birth rate between the groups for either fresh or thawed embryo transfer. There was no difference between the proportions of women in either group or the number of treatments needed to achieve a live birth. Heterosexuals had a higher prevalence of smokers (9.2%), uterine polyps (7.2%) or previous children (11.3%) than lesbians (smokers 2.8%, P = 0.03; polyps 1.8%, P = 0.03; child 2.5%, P = 0.003).

LIMITATIONS, REASONS FOR CAUTION

This study is limited to women living in stable relationships undergoing treatment with donated sperm in a clinical setting and may not apply to single women or those undergoing home inseminations.

WIDER IMPLICATIONS OF THE FINDINGS

These results may influence healthcare policy decisions as well as increase the quality of clinical care and medical knowledge of healthcare professionals. The data also have important implications for individuals regarding screening, infertility diagnostic procedures and treatment types offered to heterosexuals and lesbians seeking pregnancy through sperm donation.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was granted by the Stiftelsen Familjeplaneringsfonden i Uppsala; the Swedish Research Council for Health, Working Life and Welfare; and the Marianne and Marcus Wallenberg Foundation. The authors report no conflicts of interest.