Prospective study of cigarette smoking and fecundability

Lifestyle and fertility-specific quality of life affect reproductive outcomes in couples undergoing in vitro fertilization

Objective

A Mediterranean dietary pattern, sleeping habits, physical activity, and lifestyle appear to affect reproductive health. There are few reports about whether fertility-specific quality of life (QOL) is linked to infertility treatment outcomes. The aim of this study is to investigate when lifestyle factors and fertility-specific QOL are comprehensively considered, which factors influence assisted reproductive technology (ART) outcomes.

Methods

This prospective cohort includes 291 women undergoing a first ART treatment at multiple centers in Japan and was designed to evaluate the influence of diet, physical activity, sleeping pattern, computer use duration, and fertility-specific quality of life tool (FertiQoL) score on ART treatment outcomes using a questionnaire. The primary endpoint was the good-quality blastocyst rate per oocyte retrieval and the secondary endpoints were a positive pregnancy test and gestational sac (GS) detection.

Results

The good-quality blastocyst rate per oocyte retrieval tended to be negatively associated with frequent fish consumption. After all embryo transfer (ET) cycles, a positive pregnancy test tended to be positively associated with longer sleep and longer computer use (OR = 1.6, 95% CI = 0.9-2.7 and OR = 1.7, CI = 1.0-2.8, respectively) and negatively associated with a smoking partner (OR = 0.6, CI = 0.3-1.0). GS detection was positively and significantly associated with frequent olive oil intake and longer computer use (OR = 1.7, CI = 1.0-3.0 and OR = 1.7, CI = 1.0-3.0, respectively). After ET cycles with a single blastocyst, a positive pregnancy test was positively and significantly associated with longer computer use (OR = 2.0, CI = 1.1-3.7), while GS detection was significantly more likely in women with longer computer use (OR = 2.1, CI = 1.1-3.8) and tended to be more likely in women with a higher FertiQoL Total scaled treatment score (OR = 1.8, CI = 1.0-3.3). p < 0.05 was considered statistically significant and 0.05 ≤ p <0.01 as tendency.

Conclusions

Olive oil may be an important factor in dietary habits. Fertility-specific QOL and smoking cessation guidance for partners are important for infertile couples.

Unraveling the link: environmental tobacco smoke exposure and its impact on infertility among American women (18-50 years)

Purpose

The detrimental effects of environmental tobacco smoke (ETS) on women's reproductive health have been widely recognized. However, the detailed association between exposure to environmental tobacco smoke and the incidence of infertility remains under-explored. This investigation focuses on exploring this potential connection.

Methods

For this analysis, we extracted data from the US National Health and Nutrition Examination Survey (NHANES) database, covering the years 2013 to 2018, focusing on individuals with recorded serum cotinine levels and infertility information. ETS exposure and fertility status were analyzed as independent and dependent variables, respectively. We applied weighted multivariate logistic regression method to evaluate the impact of ETS on infertility, including subgroup analyses for more detailed insights.

Results

The study encompassed 3,343 participants. Logistic regression analysis revealed a notable positive correlation between ETS exposure and infertility, with an odds ratio (OR) of 1.64 (95% Confidence Interval [CI]: 1.14-2.36). We observed a non-linear relationship between ETS exposure and infertility risk. Notably, infertility risk increased by 64% in serum cotinine levels above 0.136 compared to that in serum cotinine levels below 0.011. Further, subgroup analysis and interaction tests showed consistent results across different segments, underscoring the robustness of the ETS-infertility link.

Conclusion

Our findings suggest that environmental tobacco smoke exposure may be a contributing factor to infertility. These results reinforce the recommendation for women in their reproductive years to avoid ETS exposure, especially when planning for pregnancy.

The Association between Circulating Lipids and Female Infertility Risk: A Univariable and Multivariable Mendelian Randomization Analysis

BACKGROUND

Although observational studies have demonstrated that blood lipids are associated with female infertility, the causality of this association remains unclear. We performed a univariable and multivariable Mendelian randomization (MR) analysis to evaluate the causal relationship between blood lipids and female infertility.

METHODS

Single-nucleotide polymorphisms associated with lipid traits in univariate analysis were obtained from the Million Veteran Program (MVP) and Global Lipids Genetics Consortium (GLGC), involving up to 215,551 and 188,577 European individuals, respectively. Blood lipids in multivariate analysis were obtained from the latest genome-wide association study meta-analysis with lipid levels in 73 studies encompassing >300,000 participants. Data on female infertility were obtained from the FinnGen Consortium R6 release, which included 6481 samples and 75,450 controls. Subsequently, MR analysis was performed using inverse variance-weighted (IVW), weighted median, weighted-mode, simple-mode and MR-Egger regression to demonstrate the causal relationship between lipids and female infertility.

RESULTS

After controlling confounding factors including body mass index and age at menarche, two-sample MR demonstrated that genetically predicted LDL-C and TC were causally associated with the risk of female infertility (When the genetic instruments come from the MVP database, LDL-C and female infertility, IVW OR: 1.13, 95% CI: 1.001-1.269, p = 0.047; TC and female infertility, IVW OR: 1.16, 95% CI: 1.018-1.317, p = 0.025, and when the genetic instruments came from the GLGC database, LDL-C and female infertility, IVW OR: 1.10, 95% CI: 1.008-1.210, p = 0.033; TC and female infertility, IVW OR: 1.14, 95% CI: 1.024-1.258, p = 0.015). However, the IVW estimate showed that HDL-C was not significantly associated with the risk of female infertility (when the genetic instruments came from the MVP database, IVW OR: 1.00, 95% CI: 0.887-1.128, p = 0.999; when the genetic instruments came from the GLGC database, IVW OR: 1.00, 95% CI: 0.896-1.111, p = 0.968). The multivariable MR analysis also provided evidence that LDL-C (OR: 1.12, 95% CI: 1.006-1.243, p = 0.042) was significantly associated with the risk of female infertility after considering the correlation of all lipid-related traits.

CONCLUSION

These findings support a causal relationship between increased LDL-cholesterol and increased female infertility risk. Furthermore, the association between lipid-related traits and female infertility risk merits more studies.

The impact of e-cigarette exposure on different organ systems: A review of recent evidence and future perspectives

The use of electronic cigarettes (e-cigs) is rapidly increasing worldwide and is promoted as a smoking cessation tool. The impact of traditional cigs on human health has been well-defined in both animal and human studies. In contrast, little is known about the adverse effects of e-cigs exposure on human health. This review summarizes the impact of e-cigs exposure on different organ systems based on the rapidly expanding recent evidence from experimental and human studies. A number of growing studies have shown the adverse effects of e-cigs exposure on various organ systems. The summarized data in this review indicate that while e-cigs use causes less adverse effects on different organs compared to traditional cigs, its long-term exposure may lead to serious health effects. Data on short-term organ effects are limited and there is no sufficient evidence on long-term organ effects. Moreover, the adverse effects of secondhand and third hand e-cigs vapour exposure have not been thoroughly investigated in previous studies. Although some studies demonstrated e-cigs used as a smoking cessation tool, there is a lack of strong evidence to support it. While some researchers suggested e-cigs as a safer alternative to tobacco smoking, their long-term exposure health effects remain largely unknown. Therefore, more epidemiological and prospective studies including mechanistic studies are needed to address the potential adverse health effects of e-cigs to draw a firm conclusion about their safe use. A wide variation in e-cigs products and the lack of standardized testing methods are the major barriers to evaluating the existing data. Specific regulatory guidelines for both e-cigs components and the manufacturing process may be effective to protect consumer health.

Socioeconomic status and fecundability in a Danish preconception cohort

STUDY QUESTION

To what extent is socioeconomic status (SES), as measured by educational attainment and household income, associated with fecundability in a cohort of Danish couples trying to conceive?

SUMMARY ANSWER

In this preconception cohort, lower educational attainment and lower household income were associated with lower fecundability after adjusting for potential confounders.

WHAT IS KNOWN ALREADY

Approximately 15% of couples are affected by infertility. Socioeconomic disparities in health are well established. However, little is known about socioeconomic disparity and its relation to fertility.

STUDY DESIGN, SIZE, DURATION

This is a cohort study of Danish females aged 18-49 years who were trying to conceive between 2007 and 2021. Information was collected via baseline and bi-monthly follow-up questionnaires for 12 months or until reported pregnancy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Overall, 10 475 participants contributed 38 629 menstrual cycles and 6554 pregnancies during a maximum of 12 cycles of follow-up. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% CIs.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared with upper tertiary education (highest level), fecundability was substantially lower for primary and secondary school (FR: 0.73, 95% CI: 0.62-0.85), upper secondary school (FR: 0.89, 95% CI: 0.79-1.00), vocational education (FR: 0.81, 95% CI: 0.75-0.89), and lower tertiary education (FR: 0.87, 95% CI: 0.80-0.95), but not for middle tertiary education (FR: 0.98, 95% CI: 0.93-1.03). Compared with a monthly household income of >65 000 DKK, fecundability was lower for household income <25 000 DKK (FR: 0.78, 95% CI: 0.72-0.85), 25 000-39 000 DKK (FR: 0.88, 95% CI: 0.82-0.94), and 40 000-65 000 DKK (FR: 0.94, 95% CI: 0.88-0.99). The results did not change appreciably after adjustment for potential confounders.

LIMITATIONS, REASONS FOR CAUTION

We used educational attainment and household income as indicators of SES. However, SES is a complex concept, and these indicators may not reflect all aspects of SES. The study recruited couples planning to conceive, including the full spectrum of fertility from less fertile to highly fertile individuals. Our results may generalize to most couples who are trying to conceive.

WIDER IMPLICATIONS OF THE FINDINGS

Our results are consistent with the literature indicating well-documented inequities in health across socioeconomic groups. The associations for income were surprisingly strong considering the Danish welfare state. These results indicate that the redistributive welfare system in Denmark does not suffice to eradicate inequities in reproductive health.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the Department of Clinical Epidemiology, Aarhus University and Aarhus University Hospital, and the National Institute of Child Health and Human Development (RO1-HD086742, R21-HD050264, and R01-HD060680). The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Associations between smoking status and infertility: a cross-sectional analysis among USA women aged 18-45 years

Background

Although many studies have proven the harmful effects of smoking on human health, the associations between smoking status and infertility are limited in large epidemiologic studies. We aimed to investigate the associations between smoking status and infertility among child-bearing women in the United States of America (USA).

Methods

A total of 3,665 female participants (aged 18-45) from the National Health and Nutrition Examination Survey (NHANES) (2013-2018) were included in this analysis. All data were survey-weighted, and corresponding logistic regression models were performed to investigate the associations between smoking status and infertility.

Results

In a fully adjusted model, the risk of infertility was found to be increased by 41.8% among current smokers compared to never smokers (95% CI: 1.044-1.926, P=0.025). In the subgroup analysis, the odds ratios (95% CI) of the risk of infertility for current smokers were 2.352 (1.018-5.435) in the unadjusted model for Mexican American, 3.675 (1.531-8.820) in the unadjusted model but 2.162 (0.946-4.942) in fully adjusted model for people aged 25-31, 2.201 (1.097-4.418) in the unadjusted model but 0.837 (0.435-1.612) in fully adjusted model for people aged 32-38.

Conclusion

Current smokers was associated with a higher risk of infertility. The underlying mechanism of these correlations still needs more research. Our findings indicated that quitting smoking may serve as a simple index to reduce the risk of infertility.

Associations between health behaviours, fertility and reproductive outcomes: triangulation of evidence in the Norwegian Mother, Father and Child Cohort Study (MoBa)

BACKGROUND

Guidance to improve fertility includes reducing alcohol and caffeine consumption, achieving healthy weight-range and stopping smoking. Advice is informed by observational evidence, which is often biased by confounding.

METHODS

This study primarily used data from a pregnancy cohort, the Norwegian Mother, Father and Child Cohort Study. First, we conducted multivariable regression of health behaviours (alcohol and caffeine consumption, body-mass index (BMI), and smoking) on fertility outcomes (e.g. time to conception) and reproductive outcomes (e.g. age at first birth) (n = 84,075 females, 68,002 males), adjusting for birth year, education and attention-deficit and hyperactive-impulsive (ADHD) traits. Second, we used individual-level Mendelian randomisation (MR) to explore possible causal effects of health behaviours on fertility/reproductive outcomes (n = 63,376 females, 45,460 males). Finally, we performed summary-level MR for available outcomes in UK Biobank (n = 91,462-1,232,091) and controlled for education and ADHD liability using multivariable MR.

RESULTS

In multivariable regression analyses, higher BMI associated with fertility (longer time to conception, increased odds of infertility treatment and miscarriage), and smoking was associated with longer time to conception. In individual-level MR analyses, there was strong evidence for effects of smoking initiation and higher BMI on younger age at first birth, of higher BMI on increased time to conception, and weak evidence for effects of smoking initiation on increased time to conception. Age at first birth associations were replicated in summary-level MR analysis; however, effects attenuated using multivariable MR.

CONCLUSIONS

Smoking behaviour and BMI showed the most consistent associations for increased time to conception and a younger age at first birth. Given that age at first birth and time to conception are positively correlated, this suggests that the mechanisms for reproductive outcomes are distinct to the mechanisms acting on fertility outcomes. Multivariable MR suggested that effects on age at first birth might be explained by underlying liability to ADHD and education.

Paternal preconception modifiable risk factors for adverse pregnancy and offspring outcomes: a review of contemporary evidence from observational studies

BACKGROUND

The preconception period represents transgenerational opportunities to optimize modifiable risk factors associated with both short and long-term adverse health outcomes for women, men, and children. As such, preconception care is recommended to couples during this time to enable them to optimise their health in preparation for pregnancy. Historically, preconception research predominately focuses on maternal modifiable risks and health behaviours associated with pregnancy and offspring outcomes; limited attention has been given to inform paternal preconception health risks and outcomes. This systematic review aims to advance paternal preconception research by synthesising the current evidence on modifiable paternal preconception health behaviours and risk factors to identify associations with pregnancy and/or offspring outcomes.

METHODS

Medline, Embase, Maternity and Infant care, CINAHL, PsycINFO, Scopus, and ISI Proceedings were searched on the 5^th of January 2023, a date limit was set [2012-2023] in each database. A Google Scholar search was also conducted identifying all other relevant papers. Studies were included if they were observational, reporting associations of modifiable risk factors in the preconception period among males (e.g., identified as reproductive partners of pregnant women and/or fathers of offspring for which outcomes were reported) with adverse pregnancy and offspring outcomes. Study quality was assessed using the Newcastle-Ottawa Scale. Exposure and outcome heterogeneity precluded meta-analysis, and results were summarised in tables.

RESULTS

This review identified 56 cohort and nine case control studies. Studies reported on a range of risk factors and/or health behaviours including paternal body composition (n = 25), alcohol intake (n = 6), cannabis use (n = 5), physical activity (n = 2), smoking (n = 20), stress (n = 3) and nutrition (n = 13). Outcomes included fecundability, IVF/ISCI live birth, offspring weight, body composition/BMI, asthma, lung function, leukemia, preterm birth, and behavioural issues. Despite the limited number of studies and substantial heterogeneity in reporting, results of studies assessed as good quality showed that paternal smoking may increase the risk of birth defects and higher paternal BMI was associated with higher offspring birthweight.

CONCLUSION

The current evidence demonstrates a role of paternal preconception health in influencing outcomes related to pregnancy success and offspring health. The evidence is however limited and heterogenous, and further high-quality research is needed to inform clinical preconception care guidelines to support men and couples to prepare for a health pregnancy and child.

Preconceptional thyroid stimulating hormone level and fecundity: a community-based cohort study of time to pregnancy

OBJECTIVE

To investigate the association between preconception thyroid stimulating hormone (TSH) level and time to pregnancy within a community-based population.

DESIGN

A community-based cohort study.

SETTING

Two free preconception check-up centers.

PATIENT(S)

Women who enrolled in the National Free Preconception Check-up Projects from January 1, 2018 to December 31, 2018 in Tianhe and Zengcheng districts of Guangzhou city.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Time to pregnancy.

RESULT(S)

A total of 1,478 women were eligible for the analysis; of these, 1,401 had a preconception TSH level within the range of 0.50 and 5.59 mIU/L (2.5th-97.5th percentiles) were taken as target study population. Among them, 968 (69.1%) couples achieved pregnancy within the first 6 months and 1,082 (77.2%) within 12 months. Dichotomized by the recommended cut-off value of 2.5 mIU/L, the percentage of women conceived in the high TSH level category (2.50-5.59 mIU/L) was comparable to that of the low category (0.50-2.49 mIU/L) (79.0% vs. 78.1%), with a crude fecundity odd ratio of 0.99 (95% confidence interval at 0.87-1.13). No statistically significant difference was observed after the adjustment in all models. Continuous TSH level was further examined, and the nonlinear association between TSH level and fecundity odds ratios was of no statistical significance.

CONCLUSION(S)

Preconception TSH level was not associated with fecundity in a healthy community-based population. Women attempting pregnancy with a TSH level ≥ 2.5 mIU/L can be reassured that they are unlikely to have an increased time to pregnancy.

Environmental toxicants and male fertility

Semen quality has declined especially among Western men. Experimental and epidemiological studies have shown potential links between exposure to environmental toxicants and poor male fertility. Some environmental exposures in utero can disrupt fetal testicular function and result in cryptorchidism, low semen quality, low serum testosterone levels, and low fertility. Environmental exposure in childhood and adulthood can also adversely affect germ cells, Sertoli cells, Leydig cells, or the hypothalamic-pituitary-testicular axis, resulting in impaired male fertility. In this review, we report the latest results from human studies that investigated the role of endocrine disrupting chemicals, heavy metals, tobacco smoking, alcohol drinking, and use of marijuana in low semen quality and impaired male fertility. Current evidence suggests the relationship between these environmental factors and low male fertility; however, some factors showed conflicting results which need further investigation.

Modifiable Risk Factor Score and Fecundability in a Preconception Cohort in Singapore

IMPORTANCE

Although multiple modifiable risk factors have been identified for reduced fecundability (defined as lower probability of conception within a menstrual cycle), no scoring system has been established to systematically evaluate fecundability among females who are attempting to conceive.

OBJECTIVE

To examine the association of a risk score based on 6 modifiable factors with fecundability, and to estimate the percentage reduction in incidence of nonconception if all study participants achieved a minimal risk score level.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study obtained data from the S-PRESTO (Singapore Preconception Study of Long-Term Maternal and Child Outcomes) prospective cohort study. Females of reproductive age who were trying to conceive were enrolled from February 2015 to October 2017 and followed for 1 year, ending in November 2018. Data were analyzed from March to May 2022.

EXPOSURES

A reduced fecundability risk score was derived by giving participants 1 point for each of the following factors: unhealthy body mass index, unhealthy diet, smoking, alcohol intake, folic acid supplement nonuser, and older maternal age. Total scores ranged from 0 to 6 and were classified into 5 levels: level 1 (score of 0 or 1), level 2 (score of 2), level 3 (score of 3), level 4 (score of 4), and level 5 (score of 5 or 6).

MAIN OUTCOMES AND MEASURES

Fecundability, measured by time to conception in cycles, was analyzed using discrete-time proportional hazards models with confounder adjustment.

RESULTS

A total of 937 females (mean [SD] age, 30.8 [3.8] years) were included, among whom 401 (42.8%) spontaneously conceived within 1 year of attempting conception; the median (IQR) number of cycles before conception was 4 (2-7). Compared with participants with a level 1 risk score, those with level 2, 3, 4, and 5 risk scores had reductions in fecundability of 31% (adjusted fecundability ratio [FR], 0.69; 95% CI, 0.54-0.88), 41% (FR, 0.59; 95% CI, 0.45-0.78), 54% (FR, 0.46; 95% CI, 0.31-0.69) and 77% (FR, 0.23; 95% CI, 0.07-0.73), respectively. Assessment of the population attributable fraction showed that all participants achieving a minimal (level 1) risk level would be associated with a reduction of 34% (95% CI, 30%-39%) in nonconception within a year.

CONCLUSIONS AND RELEVANCE

Results of this study revealed the co-occurrence of multiple modifiable risk factors for lowered fecundability and a substantially higher conception rate among participants with no or minimal risk factors. The risk assessment scoring system proposed is a simple and potentially useful public health tool for mitigating risks and guiding those who are trying to conceive.

Dietary Supplement Intake and Fecundability in a Singapore Preconception Cohort Study

Subfertility is a global problem affecting millions worldwide, with declining total fertility rates. Preconception dietary supplementation may improve fecundability, but the magnitude of impact remains unclear. This prospective cohort study aimed to examine the association of preconception micronutrient supplements with fecundability, measured by time to pregnancy (TTP). The study was conducted at KK Women's and Children's Hospital, Singapore, between February 2015 and October 2017, on 908 women aged 18-45 years old, who were trying to conceive and were enrolled in the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO). Baseline sociodemographic characteristics and supplement intake were collected through face-to-face interviews. The fecundability ratio (FR) was estimated using discrete-time proportional hazard modelling. Adjusting for potentially confounding variables, folic acid (FA) (FR 1.26, 95% confidence interval 1.03-1.56) and iodine (1.28, 1.00-1.65) supplement users had higher fecundability compared to non-users. Conversely, evening primrose oil supplement users had lower fecundability (0.56, 0.31-0.99) than non-users. In this study, preconception FA and iodine supplementation were associated with shortened TTP, while evening primrose oil use was associated with longer TTP. Nonetheless, the association between supplement use and the magnitude of fecundability changes will need to be further confirmed with well-designed randomised controlled trials.

Cigarette smoke is associated with up-regulation of inducible NOS and COX-2 protein expression and activity in granulosa cells of women undergoing in vitro fertilization

Cigarette smoke exposure represents a well-established ovotoxic exogenous stress, but the molecular mechanisms underlying of this effect are still unclear. Cigarette smoke upregulates inflammatory genes in the female reproductive organs, therefore an abnormal inflammation response may contribute to the impairment of female fertility. In this study we investigated for the first time the effect of cigarette smoke exposure on NOS and COX expression and activity and on their transcription factors (CREB and NF-kB) in human GCs and on the release of NO and PGE₂ in the FF in smoking and non-smoking patients undergoing IVF treatment. In addition, correlation analysis between AMH serum levels, an index of ovarian reserve, and smoking exposure or iNOS and COX-2 protein expression levels were performed using a Pearson correlation method. Cigarette smoke exposure resulted in a significant increase of iNOS and COX-2 protein expression together with an increase of iNOS activity and PGE₂ levels. pNF-kB and pCREB protein expression were upregulated in the GCs of smokers compared to non-smokers. The habit of smoking was negatively correlated with serum AMH levels, and positively correlated with iNOS and COX-2 protein expression levels. The data presented in the current study revealed a novel molecular mechanism underlying the toxic effects of cigarette smoke on fertility. Additional pathways mediating the effects of cigarette smoke exposure in human GCs cannot be excluded and should be investigated in future studies.

Indoor and outdoor air pollution and couple fecundability: a systematic review

BACKGROUND

Air pollution is both a sensory blight and a threat to human health. Inhaled environmental pollutants can be naturally occurring or human-made, and include traffic-related air pollution (TRAP), ozone, particulate matter (PM) and volatile organic compounds, among other substances, including those from secondhand smoking. Studies of air pollution on reproductive and endocrine systems have reported associations of TRAP, secondhand smoke (SHS), organic solvents and biomass fueled-cooking with adverse birth outcomes. While some evidence suggests that air pollution contributes to infertility, the extant literature is mixed, and varying effects of pollutants have been reported.

OBJECTIVE AND RATIONALE

Although some reviews have studied the association between common outdoor air pollutants and time to pregnancy (TTP), there are no comprehensive reviews that also include exposure to indoor inhaled pollutants, such as airborne occupational toxicants and SHS. The current systematic review summarizes the strength of evidence for associations of outdoor air pollution, SHS and indoor inhaled air pollution with couple fecundability and identifies gaps and limitations in the literature to inform policy decisions and future research.

SEARCH METHODS

We performed an electronic search of six databases for original research articles in English published since 1990 on TTP or fecundability and a number of chemicals in the context of air pollution, inhalation and aerosolization. Standardized forms for screening, data extraction and study quality were developed using DistillerSR software and completed in duplicate. We used the Newcastle-Ottawa Scale to assess risk of bias and devised additional quality metrics based on specific methodological features of both air pollution and fecundability studies.

OUTCOMES

The search returned 5200 articles, 4994 of which were excluded at the level of title and abstract screening. After full-text screening, 35 papers remained for data extraction and synthesis. An additional 3 papers were identified independently that fit criteria, and 5 papers involving multiple routes of exposure were removed, yielding 33 articles from 28 studies for analysis. There were 8 papers that examined outdoor air quality, while 6 papers examined SHS exposure and 19 papers examined indoor air quality. The results indicated an association between outdoor air pollution and reduced fecundability, including TRAP and specifically nitrogen oxides and PM with a diameter of ≤2.5 µm, as well as exposure to SHS and formaldehyde. However, exposure windows differed greatly between studies as did the method of exposure assessment. There was little evidence that exposure to volatile solvents is associated with reduced fecundability.

WIDER IMPLICATIONS

The evidence suggests that exposure to outdoor air pollutants, SHS and some occupational inhaled pollutants may reduce fecundability. Future studies of SHS should use indoor air monitors and biomarkers to improve exposure assessment. Air monitors that capture real-time exposure can provide valuable insight about the role of indoor air pollution and are helpful in assessing the short-term acute effects of pollutants on TTP.

The current situation and future directions for the study on time-to-pregnancy: a scoping review

Introduction

As problems associated with infertility and population aging increase, there is a growing interest in the factors that cause a decline in human fertility. Time-to-pregnancy (TTP) is a good indicator with which to reflect human fecundability. Here, we present a comprehensive overview of this topic.

Methods

Relevant qualitative and quantitative studies were identified by searching the Web of science and PubMed electronic databases. We included all literature, written in English, from inception to the 10th April 2021 providing the focus was on TTP. We conducted a narrative synthesis using thematic analysis.

Results

Traditional TTP-related study protocols include prospective and retrospective cohorts that provide a wealth of data to reveal potential influences on TTP. Thus far, a variety of factors have been shown to be associated with TTP in couples preparing for pregnancy, including basic demographic characteristics, menstrual status, chronic disease status, environmental endocrine disruptor exposure, and lifestyles. However, there are inevitable epidemiological bias in the existing studies, including recall bias, selection bias and measurement bias. Some methodological advances have brought new opportunities to TTP research, which make it possible to develop precision interventions for population fertility. Future TTP studies should take advantage of artificial intelligence, machine learning, and high-throughput sequencing technologies, and apply medical big data to fully consider and avoid possible bias in the design.

Conclusion

There are many opportunities and future challenges for TTP related studies which would provide a scientific basis for the “precise health management” of the population preparing for pregnancy.

As the problems of infertility and population aging increase, there is a growing interest in the factors that cause a decline in human fertility. Time-to-pregnancy (TTP) is a good indicator with which to reflect human fecundability, and a longer TTP is known to reflect a reduction in fertility. Many original studies, with different designs, have used TTP to explore the factors that might influence fertility, including basic demographic characteristics, chronic disease status, environmental endocrine disruptor exposure, and lifestyles. However, much of the existing evidence is inconsistent and limited by various types of bias. This review provides a synopsis of recent TTP studies, and highlights new opportunities and future challenges.

Identification of Potential Molecular Mechanism Related to Infertile Endometriosis

Objectives

In this research, we aim to explore the bioinformatic mechanism of infertile endometriosis in order to identify new treatment targets and molecular mechanism.

Methods

The Gene Expression Omnibus (GEO) database was used to download MRNA sequencing data from infertile endometriosis patients. The “limma” package in R software was used to find differentially expressed genes (DEGs). Weighted gene co-expression network analysis (WGCNA) was used to classify genes into modules, further obtained the correlation coefficient between the modules and infertility endometriosis. The intersection genes of the most disease-related modular genes and DEGs are called gene set 1. To clarify the molecular mechanisms and potential therapeutic targets for infertile endometriosis, we used Gene Ontology (GO), Kyoto Gene and Genome Encyclopedia (KEGG) enrichment, Protein-Protein Interaction (PPI) networks, and Gene Set Enrichment Analysis (GSEA) on these intersecting genes. We identified lncRNAs and miRNAs linked with infertility and created competing endogenous RNAs (ceRNA) regulation networks using the Human MicroRNA Disease Database (HMDD), mirTarBase database, and LncRNA Disease database.

Results

Firstly, WGCNA enrichment analysis was used to examine the infertile endometriosis dataset GSE120103, and we discovered that the Meorangered1 module was the most significantly related with infertile endometriosis. The intersection genes were mostly enriched in the metabolism of different amino acids, the cGMP-PKG signaling pathway, and the cAMP signaling pathway according to KEGG enrichment analysis. The Meorangered1 module genes and DEGs were then subjected to bioinformatic analysis. The hub genes in the PPI network were performed KEGG enrichment analysis, and the results were consistent with the intersection gene analysis. Finally, we used the database to identify 13 miRNAs and two lncRNAs linked to infertility in order to create the ceRNA regulatory network linked to infertile endometriosis.

Conclusion

In this study, we used a bioinformatics approach for the first time to identify amino acid metabolism as a possible major cause of infertility in patients with endometriosis and to provide potential targets for the diagnosis and treatment of these patients.

Environmental factors in declining human fertility

A severe decline in child births has occurred over the past half century, which will lead to considerable population declines, particularly in industrialized regions. A crucial question is whether this decline can be explained by economic and behavioural factors alone, as suggested by demographic reports, or to what degree biological factors are also involved. Here, we discuss data suggesting that human reproductive health is deteriorating in industrialized regions. Widespread infertility and the need for assisted reproduction due to poor semen quality and/or oocyte failure are now major health issues. Other indicators of declining reproductive health include a worldwide increasing incidence in testicular cancer among young men and alterations in twinning frequency. There is also evidence of a parallel decline in rates of legal abortions, revealing a deterioration in total conception rates. Subtle alterations in fertility rates were already visible around 1900, and most industrialized regions now have rates below levels required to sustain their populations. We hypothesize that these reproductive health problems are partially linked to increasing human exposures to chemicals originating directly or indirectly from fossil fuels. If the current infertility epidemic is indeed linked to such exposures, decisive regulatory action underpinned by unconventional, interdisciplinary research collaborations will be needed to reverse the trends.

Association between pregnancy intention and preconception health behaviors

BACKGROUND

Female adolescent and young adult (AYA) cancer survivors face higher infertility and pregnancy risks than peers with no cancer history. Preconception health behaviors such as physical activity (PA), tobacco smoking, and alcohol intake influence reproductive outcomes. In general populations, pregnancy intention is positively associated with healthy preconception behaviors, but it has not been studied among AYA survivors. The authors hypothesized that higher pregnancy intention would be associated with healthier behaviors, especially among AYA survivors with perceived infertility risk.

METHODS

A cross-sectional analysis was conducted with data collected between 2013 and 2017 from 1071 female AYA survivors aged 18 to 39 years who had completed their primary cancer treatment and enrolled in an ovarian function study. Self-reported intention dimensions were measured as a pregnancy intention score (PIS) and trying now to become pregnant. Multivariable linear (PA), binary (smoking), and ordinal (alcohol use) logistic regressions were used to estimate associations between intentions and preconception behaviors, with adjustments made for demographic and cancer characteristics. Effect modification by perceived infertility risk was assessed.

RESULTS

The mean PIS was 1.1 (SD, 0.77) on a 0 to 2 scale (2 = high intention), and 8.9% were attempting pregnancy now. A higher PIS was associated with increased PA (β, 0.08; 95% CI, 0.11-1.04), whereas ambivalence in pregnancy intention was associated with lower alcohol consumption (odds ratio, 0.72; 95% CI, 0.55-0.95). Pregnancy intentions were not associated with smoking. Perceived infertility risk strengthened the relationship between PIS and PA (P < .05).

CONCLUSIONS

Pregnancy intentions were associated with some healthier preconception behaviors in AYA survivors. Medical professionals caring for AYA survivors may consider pregnancy intention screening to guide conversations on preconception health.

Predictive models of pregnancy based on data from a preconception cohort study

STUDY QUESTION

Can we derive adequate models to predict the probability of conception among couples actively trying to conceive?

SUMMARY ANSWER

Leveraging data collected from female participants in a North American preconception cohort study, we developed models to predict pregnancy with performance of ∼70% in the area under the receiver operating characteristic curve (AUC).

WHAT IS KNOWN ALREADY

Earlier work has focused primarily on identifying individual risk factors for infertility. Several predictive models have been developed in subfertile populations, with relatively low discrimination (AUC: 59-64%).

STUDY DESIGN, SIZE, DURATION

Study participants were female, aged 21-45 years, residents of the USA or Canada, not using fertility treatment, and actively trying to conceive at enrollment (2013-2019). Participants completed a baseline questionnaire at enrollment and follow-up questionnaires every 2 months for up to 12 months or until conception. We used data from 4133 participants with no more than one menstrual cycle of pregnancy attempt at study entry.

PARTICIPANTS/MATERIALS, SETTING, METHODS

On the baseline questionnaire, participants reported data on sociodemographic factors, lifestyle and behavioral factors, diet quality, medical history and selected male partner characteristics. A total of 163 predictors were considered in this study. We implemented regularized logistic regression, support vector machines, neural networks and gradient boosted decision trees to derive models predicting the probability of pregnancy: (i) within fewer than 12 menstrual cycles of pregnancy attempt time (Model I), and (ii) within 6 menstrual cycles of pregnancy attempt time (Model II). Cox models were used to predict the probability of pregnancy within each menstrual cycle for up to 12 cycles of follow-up (Model III). We assessed model performance using the AUC and the weighted-F1 score for Models I and II, and the concordance index for Model III.

MAIN RESULTS AND THE ROLE OF CHANCE

Model I and II AUCs were 70% and 66%, respectively, in parsimonious models, and the concordance index for Model III was 63%. The predictors that were positively associated with pregnancy in all models were: having previously breastfed an infant and using multivitamins or folic acid supplements. The predictors that were inversely associated with pregnancy in all models were: female age, female BMI and history of infertility. Among nulligravid women with no history of infertility, the most important predictors were: female age, female BMI, male BMI, use of a fertility app, attempt time at study entry and perceived stress.

LIMITATIONS, REASONS FOR CAUTION

Reliance on self-reported predictor data could have introduced misclassification, which would likely be non-differential with respect to the pregnancy outcome given the prospective design. In addition, we cannot be certain that all relevant predictor variables were considered. Finally, though we validated the models using split-sample replication techniques, we did not conduct an external validation study.

WIDER IMPLICATIONS OF THE FINDINGS

Given a wide range of predictor data, machine learning algorithms can be leveraged to analyze epidemiologic data and predict the probability of conception with discrimination that exceeds earlier work.

STUDY FUNDING/COMPETING INTEREST(S)

The research was partially supported by the U.S. National Science Foundation (under grants DMS-1664644, CNS-1645681 and IIS-1914792) and the National Institutes for Health (under grants R01 GM135930 and UL54 TR004130). In the last 3 years, L.A.W. has received in-kind donations for primary data collection in PRESTO from FertilityFriend.com, Kindara.com, Sandstone Diagnostics and Swiss Precision Diagnostics. L.A.W. also serves as a fibroid consultant to AbbVie, Inc. The other authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Maternal lifestyle and nutritional habits are associated with oocyte quality and ICSI clinical outcomes

RESEARCH QUESTION

Do maternal lifestyle factors influence the incidence of oocyte dimorphisms and outcomes of intracytoplasmic sperm injection (ICSI) cycles?

DESIGN

A total of 752 female patients undergoing an ICSI cycle at a private university-affiliated IVF centre from January 2015 to December 2019 were included in this historical cohort study. Before starting ovarian stimulation, participants completed a questionnaire on cigarette smoking habits, consumption of alcoholic beverages, refined sugar, artificial sweeteners, soft drinks, fruits, legumes and vegetables, milk and dairy, and meat, as well as exercise frequency over the past 6 months. Oocyte morphology was evaluated before ICSI. The influence of maternal lifestyle factors on the incidence of oocyte dimorphisms and ICSI outcomes was evaluated by multivariate general linear models and generalized linear models, adjusted for potential confounders. The main outcome measures were the incidence of oocyte dimorphisms per cycle and clinical outcomes.

RESULTS

Lifestyle factors and nutritional habits such as cigarette smoking, and the consumption of alcohol, refined sugar and artificial sweeteners, were positively associated with incidence of several oocyte dimorphisms and negatively associated with the response to ovarian stimulation and embryo development. Negative relationships were also observed between these habits and clinical outcomes, apart from miscarriage rate, in which positive relationships were observed. Significant negative dose-dependent relationships between these habits and implantation rates were noted (P < 0.001). Alcoholic beverage consumption also showed inverse dose-dependent relationships with clinical pregnancy and live birth rates. Live birth rate was also negatively associated with cigarette smoking, in a dose-dependent manner.

CONCLUSIONS

Poor maternal habits were associated with reduced oocyte quality and ICSI outcomes in this study. Many of these associations were shown to be dose-dependent.

Antibiotics and fecundability among female pregnancy planners: a prospective cohort study

STUDY QUESTION

To what extent is female preconception antibiotic use associated with fecundability?

SUMMARY ANSWER

Preconception antibiotic use overall was not appreciably associated with fecundability.

WHAT IS KNOWN ALREADY

Antibiotics are commonly used by women and are generally thought to be safe for use during pregnancy. However, little is known about possible effects of antibiotic use on fecundability, the per-cycle probability of conception. Previous research on this question has been limited to occupational rather than therapeutic exposure.

STUDY DESIGN, SIZE, DURATION

We analyzed data from an Internet-based preconception cohort study of 9524 female pregnancy planners aged 21-45 years residing in the USA and Canada who had been attempting to conceive for six or fewer cycles at study entry. Participants enrolled between June 2013 and September 2020 and completed baseline and bimonthly follow-up questionnaires for up to 12 months or until a reported pregnancy, whichever came first. The questions pertaining to antibiotic type and indication were added to the PRESTO questionnaires in March 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We assessed antibiotic use in the previous 4 weeks at baseline and on each follow-up questionnaire. Participants provided the name of the specific antibiotic and the indication for use. Antibiotics were classified based on active ingredient (penicillins, macrolides, nitrofurantoin, nitroimidazole, cephalosporins, sulfonamides, quinolones, tetracyclines, lincosamides), and indications were classified by type of infection (respiratory, urinary tract, skin, vaginal, pelvic, and surgical). Participants reported pregnancy status on follow-up questionnaires. We used proportional probabilities regression to estimate fecundability ratios (FR), the per-cycle probability of conception comparing exposed with unexposed individuals, and 95% CI, adjusting for sociodemographics, lifestyle factors, and reproductive history.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, women who used antibiotics in the past 4 weeks at baseline had similar fecundability to those who had not used antibiotics (FR: 0.98, 95% CI: 0.89-1.07). Sulfonamides and lincosamides were associated with slightly increased fecundability (FR: 1.39, 95% CI: 0.90-2.15, and FR: 1.58 95% CI: 0.96-2.60, respectively), while macrolides were associated with slightly reduced fecundability (FR: 0.70, 95% CI: 0.47-1.04). Analyses of the indication for antibiotic use suggest that there is likely some confounding by indication.

LIMITATIONS, REASONS FOR CAUTION

Findings were imprecise for some antibiotic classes and indications for use owing to small numbers of antibiotic users in these categories. There are likely heterogeneous effects of different combinations of indications and treatments, which may be obscured in the overall null results, but cannot be further elucidated in this analysis.

WIDER IMPLICATIONS OF THE FINDINGS

There is little evidence that most antibiotics are associated with reduced fecundability. Antibiotics and the infections they treat are likely associated with fecundability through differing mechanisms, resulting in their association with increased fecundability in some circumstances and decreased fecundability in others.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported through funds provided by the National Institute of Child Health and Human Development, National Institutes of Health (R01-HD086742, R21-HD072326). L.A.W. has received in-kind donations from Swiss Precision Diagnostics, Sandstone Diagnostics, Fertility Friend, and Kindara for primary data collection in PRESTO. The other authors have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Successful Smoking Cessation among Women Smokers Based on Utilizing National Smoking Cessation Service Type in Korea

Background: This study aimed to evaluate the successful smoking cessation across different national smoking cessation services. Methods: This study included data that had been previously entered into the integrated information system for smoking cessation services and comprised 144,688 participants after excluding missing data. These clinics provide face-to-face counseling, phone calls, text messages, and e-mail services for six months and nine sessions. Results: The women-only program had the lowest success rate (11.3%). Compared with the women-only program, the six-month success rate of smoking cessation clinic at public health centers (OR = 3.72, CI = [3.52, 3.92]), visiting-type smoking cessation clinics (OR = 2.97, CI = [2.79, 3.16]), the residential 4 -night 5-day program (OR = 7.79, CI = [6.49, 9.35]), and a program for inpatients (OR = 2.36, CI = [1.89, 2.94]) showed a significant increase. Conclusions: Emotional labor workers who participated in the women-only program had low smoking cessation success rates, while those who participated in the residential 4-night 5-day program had high success rates.

Fecundability and Sterility by Age: Estimates Using Time to Pregnancy Data of Japanese Couples Trying to Conceive Their First Child with and without Fertility Treatment

Fecundability, the probability of conception in a month or in a menstrual cycle, varies across and within age groups for both women and men. Fertility treatment has become common in a number of countries including Japan, but its impact on the age pattern of fecundability is unknown. By utilizing the previously collected data on time to pregnancy (TTP) of Japanese couples trying to conceive their first child, the present study aimed to estimate fecundability and sterility by women’s age and to assess how the estimates may differ by including or excluding assisted conceptions. Duration between discontinuing contraception and conception (including both natural and assisted) resulted in a live birth was called TTP-all, and the duration ending with natural conception was called TTP-natural. TTP-natural was censored when a participant received fertility consultation or treatment. A zero-inflated beta distribution model was used to estimate a proportion of sterile (zero probability of conception) and a distribution of fecundability for each age group. Parameters of the distribution were estimated using the maximum likelihood method. When TTP-all and TTP-natural were used, the sterile proportion of the whole sample was, respectively, 2% and 14%, and the median (interquartile range) of fecundability was, respectively, 0.10 (0.04, 0.19) and 0.11 (0.05, 0.19). The median (interquartile range) of fecundability was 0.18 (0.10, 0.29) for women aged 24 years or younger and 0.05 (0.02, 0.13) for 35–39 years old when TTP-all was used, and the estimates were quite similar with those based on TTP-natural: it was 0.18 (0.10, 0.29) for women aged 24 years or younger and 0.06 (0.00, 0.15) for 35–39 years old. Exclusion of assisted conceptions resulted in larger proportions of sterility, but it had little impact on median or interquartile ranges of fecundability estimates. Fecundability is overall lower at higher ages, while interquartile ranges are overlapping, suggesting that inter-individual variability of fecundability within an age group is as large as the variability across age groups.

A systematic review of quantitative bias analysis applied to epidemiological research

BACKGROUND

Quantitative bias analysis (QBA) measures study errors in terms of direction, magnitude and uncertainty. This systematic review aimed to describe how QBA has been applied in epidemiological research in 2006-19.

METHODS

We searched PubMed for English peer-reviewed studies applying QBA to real-data applications. We also included studies citing selected sources or which were identified in a previous QBA review in pharmacoepidemiology. For each study, we extracted the rationale, methodology, bias-adjusted results and interpretation and assessed factors associated with reproducibility.

RESULTS

Of the 238 studies, the majority were embedded within papers whose main inferences were drawn from conventional approaches as secondary (sensitivity) analyses to quantity-specific biases (52%) or to assess the extent of bias required to shift the point estimate to the null (25%); 10% were standalone papers. The most common approach was probabilistic (57%). Misclassification was modelled in 57%, uncontrolled confounder(s) in 40% and selection bias in 17%. Most did not consider multiple biases or correlations between errors. When specified, bias parameters came from the literature (48%) more often than internal validation studies (29%). The majority (60%) of analyses resulted in >10% change from the conventional point estimate; however, most investigators (63%) did not alter their original interpretation. Degree of reproducibility related to inclusion of code, formulas, sensitivity analyses and supplementary materials, as well as the QBA rationale.

CONCLUSIONS

QBA applications were rare though increased over time. Future investigators should reference good practices and include details to promote transparency and to serve as a reference for other researchers.

Electronic Cigarettes and Fecundability: Results From a Prospective Preconception Cohort Study

Although electronic cigarette (e-cigarette) aerosol contains similar toxicants to combustible cigarettes, few studies have examined their influence on fecundability. We assessed the association between e-cigarette use and fecundability, overall and according to combustible cigarette smoking history, in a cohort of 4,586 North American women (aged 21-45 years) enrolled during 2017-2020 in Pregnancy Study Online, a Web-based prospective preconception study. Women reported current and former e-cigarette use on baseline and follow-up questionnaires, and they completed bimonthly follow-up questionnaires until self-reported pregnancy or censoring. Fecundability ratios and 95% confidence intervals were calculated using proportional probabilities models, controlling for potential confounders. Overall, 17% of women had ever used e-cigarettes and 4% were current users. Compared with never use of e-cigarettes, current e-cigarette use was associated with slightly lower fecundability (fecundability ratio = 0.84, 95% confidence interval (CI): 0.67, 1.06). Compared with current nonusers of e-cigarettes and combustible cigarettes, fecundability ratios were 0.83 (95% CI: 0.54, 1.29) for current dual users of e-cigarettes and combustible cigarettes, 0.91 (95% CI: 0.70, 1.18) for current e-cigarette users who were nonsmokers of combustible cigarettes, and 1.01 (95% CI: 0.85, 1.20) for nonusers of e-cigarettes who were current smokers of combustible cigarettes. Current e-cigarette use was associated with slightly reduced fecundability, but estimates of its independent and joint associations with combustible cigarette smoking were inconsistent and imprecise.

Model for Identifying High Carotid Body Chemosensitivity in Patients with Obstructive Sleep Apnea

OBJECTIVE

The carotid body (CB) is a major peripheral respiratory chemoreceptor. In patients with obstructive sleep apnea (OSA), high CB chemosensitivity (CBC) is associated with refractory hypertension and insulin resistance and known to further aggravate OSA. Thus, the identification of high CB (hCBC) among OSA patients is of clinical significance, but detection methods are still limited. Therefore, this study aimed to explore the association of CBC with OSA severity and to develop a simplified model that can identify patients with hCBC.

METHODS

In this cross-sectional study of subjects who underwent polysomnography (PSG), CBC was measured using the Dejours test. We defined hCBC as a decrease of >12% in respiratory rate (RR) after breathing of pure O₂. The association of CBC with OSA severity was explored by logistic regression, and a model for identifying hCBC was constructed and confirmed using receiver operating characteristic analysis.

RESULTS

Patients with OSA (n=142) and individuals without OSA (n=38) were enrolled. CBC was higher in patients with OSA than in those without OSA (% decrease in RR, 15.2%±13.3% vs 9.1%±7.5%, P<0.05). Apnea-hypopnea index (AHI), fraction of apnea-hypopnea events in rapid-eye-movement sleep (F_{events-in-REM}), and longest time of apnea (LTA) were associated with hCBC independently (odds ratio [OR]=1.048, OR=1.082, and OR=1.024 respectively; all P<0.05). The model for identifying hCBC allocated a score to each criterion according to its OR values, ie, 1 (LTA >48.4 s), 2 (AHI >15.7 events/hour), and 3 (F_{events-in-REM} >12.7%). A score of 3 or greater indicated hCBC with a sensitivity of 79.4% and specificity of 88.2%.

CONCLUSION

High CBC is associated with the severity of OSA. A simplified scoring system based on clinical variables from PSG can be used to identify hCBC.

Effects of Environment and Lifestyle Factors on Premature Ovarian Failure

Premature ovarian insufficiency (POI) or primary ovarian failure is defined as a cessation of the menstrual cycle in women younger than 40 years old. It is strictly defined as more than 4 months of oligomenorrhea or amenorrhea in a woman <40 years old, associated with at least two follicle-stimulating hormone (FSH) levels >25 U/L in the menopausal range, detected more than 4 weeks apart. It is estimated that POI was affected 1 and 2% of women. Although 80% of POI cases are of unknown etiology, it is suggested that genetic disorder, autoimmune origin, toxins, and environmental factors, as well as personal lifestyles, may be risk factors of developing POI. In this section, we will discuss the influences of environmental and lifestyle factors on POI. Moreover updated basic research findings regarding how these environmental factors affect female ovarian function via epigenetic regulations will also be discussed.

An Online Questionnaire Survey on the Sexual Life and Sexual Function of Chinese Adult Men During the Coronavirus Disease 2019 Epidemic

INTRODUCTION

There has been no report regarding the impact on male sexual life or sexual function by changes in lifestyle during the coronavirus disease 2019 (COVID-19) epidemic.

AIM

To investigate the changes in sexual life and sexual function of Chinese men during the COVID-19 epidemic.

METHODS

An online questionnaire was created and the survey was administered through social media to Chinese adult men.

MAIN OUTCOME MEASURE

The main end point was the deteriorated erectile function or ejaculatory control ability, defined by self-evaluation or by decreased International Index of Erectile Function-5 items (IIEF-5) scores or increased premature ejaculation diagnostic tool (PEDT) scores.

RESULTS

Altogether, 612 questionnaires were collected. About 322 (52.6%) subjects were unmarried. About 8.4% and 8.5% subjects reported deteriorated erectile function or ejaculation control ability by self-evaluation, whereas 31.9% and 17.9% subjects showed decreased IIEF-5 scores or increased PEDT scores. Subjects with deteriorated erectile function by self-evaluation and decreased IIEF-5 scores had higher General Anxiety Disorder-7 (P < .001 and P = .001) and higher Patient Health Questionnaire-9 score (P < .001 and P = .002) after the epidemic, decreased frequency of sexual life (P < .001 and P < .001) and physical exercise (P = .009 and .007) after the epidemic. Subjects with deteriorated ejaculation control ability by self-evaluation and increased PEDT scores had higher General Anxiety Disorder-7 (P < .001 and P < .001) and higher Patient Health Questionnaire-9 score (P < .001 and P = .002) after the epidemic. Subjects with decreased frequency of sexual life had reduced income (P < .001), increased anxiety (P < .001) and depression (P < .001). Married subjects had higher proportion of improved depression (P = .048) and increased frequency of sexual life (P = .010).

CONCLUSION

During the COVID-19 epidemic, decreased sexual function was present in a certain proportion of adult men, and the risk factors include increased anxiety and depression, and decreased frequency of sexual life. Fang D, Peng J, Liao S, et al. An Online Questionnaire Survey on the Sexual Life and Sexual Function of Chinese Adult Men During the Coronavirus Disease 2019 Epidemic. Sex Med 2021;9:100293.

A qualitative study of factors influencing male participation in fertility research

BACKGROUND

Although fertility is a couple-based outcome, fertility studies typically include far fewer males than females. We know little about which factors facilitate or inhibit male participation in fertility research. In this study we aimed to explore factors that influence male participation in fertility research among North American couples trying to conceive.

METHODS

We conducted a qualitative research study of male participation in Pregnancy Study Online (PRESTO), a prospective preconception cohort of couples actively trying to conceive in Canada and the United States. Between January-August 2019, we carried out 14 online one-on-one in-depth interviews and one online focus group of males and females with varying levels of participation. The in-depth interviews included females who enrolled in PRESTO but declined to invite their male partners to participate (n = 4), males who enrolled in PRESTO (n = 6), and males who declined to participate in PRESTO (n = 4). The focus group included 10 males who enrolled in PRESTO. We analyzed the transcriptions using inductive content analysis.

RESULTS

Male and female participants perceived that fertility is a women's health issue and is a difficult topic for men to discuss. Men expressed fears of infertility tied to masculinity. However, men were motivated to participate in fertility research to support their partners, provide data that could help others, and to learn more about their own reproductive health.

CONCLUSIONS

Male participation in fertility studies will improve our understanding of male factors contributing to fertility and reproductive health issues. Results indicate a need for more education and health communication on male fertility to normalize male participation in fertility and reproductive health research. Men are much less likely than women to participate in research on fertility and pregnancy. However, it is important for men to participate in fertility research so that we gain a better understanding of male factors that impact fertility and pregnancy outcomes. In this qualitative study, we interviewed men and women from Canada and the United States who were trying to become pregnant to understand why men choose to participate in fertility research, why men choose not to participate in fertility research, and why women choose not to invite their male partners to participate in fertility research. We found that both men and women believe fertility is a woman's health issue. Men find it difficult to talk about pregnancy and fertility and have fears of infertility tied to masculinity. However, men are motivated to participate in fertility research to support their partners, to help others, and to learn more about their own reproductive health.

Female cigarette smoking and successful fertility treatment: A Danish cohort study

INTRODUCTION

Despite smoking being a well-established risk factor for adverse pregnancy and neonatal outcomes, a substantial proportion of women of reproductive age smoke. Previously, meta-analyses have indicated a significantly negative impact of female smoking on outcomes of assisted reproduction, yet most of the included studies have several, essential methodological limitations. We aimed to investigate whether female cigarette smoking may affect the chance of achieving a clinical pregnancy and live birth among women and couples receiving medically assisted reproduction treatment.

MATERIAL AND METHODS

A cohort study with longitudinally and repeatedly collected exposure information from 1 January 2010 to 31 August 2015, including data on 1708 women and potential partners initiating either intrauterine insemination, in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) or frozen embryo transfer treatment cycles at the public Fertility Clinic, Aarhus University Hospital, Denmark. Smoking was assessed from self-reported questionnaires completed before treatment. Outcomes were a clinical pregnancy and a live birth. Information on these was obtained from the Danish national health registries, allowing complete follow-up. To evaluate associations between female occasional/daily cigarette smoking and successful medically assisted reproduction treatments, a modified Poisson regression with robust standard errors was used.

RESULTS

Female occasional/daily cigarette smoking was not associated with the chance of achieving a clinical pregnancy or a live birth in all intrauterine insemination or IVF/ICSI treatment cycles. When compared with nonsmokers, the adjusted relative risk for obtaining a live birth for those reporting smoking was 1.22 (0.70-2.12) among women initiating 1456 intrauterine insemination treatment cycles. Among women initiating 2788 IVF/ICSI treatment cycles, those reporting occasional/daily smoking had a relative risk for obtaining a live birth of 1.15 (0.82-1.60) when compared with nonsmokers.

CONCLUSIONS

Occasionally/daily cigarette smoking women had similar chance of achieving a clinical pregnancy or a live birth as the nonsmokers when receiving medically assisted reproduction treatments. However, tobacco use before and during pregnancy remains a major cause of reduced fertility as well as maternal, fetal, and infant morbidity and mortality, and should strongly be discouraged.

At-home sperm testing for epidemiologic studies: Evaluation of the Trak male fertility testing system in an internet-based preconception cohort

BACKGROUND

Semen quality assessment in population-based epidemiologic studies presents logistical and financial challenges due to reliance on centralised laboratory semen analysis. The Trak Male Fertility Testing System is an FDA-cleared and validated at-home test for sperm concentration and semen volume, with a research use only sperm motility test. Here we evaluate the Trak System's overall utility among men participating in Pregnancy Study Online (PRESTO), a web-based study of North American couples planning pregnancy.

METHODS

US male participants aged ≥21 years with ≤6 months of pregnancy attempt time at study enrolment were invited to participate in the semen testing substudy after completing their baseline questionnaire. Consenting participants received a Trak Engine (battery-powered centrifuge) and two test kits. Participants shared their test results via smartphone images uploaded to online questionnaires. Data were then linked with covariate data from the baseline questionnaire.

RESULTS

Of the 688 men invited to participate, 373 (54%) provided consent and 271 (73%) completed at least one semen test result. The distributions of semen volume, sperm concentration, motile sperm concentration, total sperm count, and total motile sperm count were similar to 2010 World Health Organization (WHO) semen parameter data of men in the general population. The overall usability score for the Trak System was 1.4 on a 5-point Likert scale (1 = Very Easy, 5 = Difficult), and 92% of participants believed they performed the test correctly and received an accurate result. Lastly, men with higher motile sperm count were more likely to report feeling "at ease" or "excited" following testing, while men with low motile sperm count were more likely to report feeling "concerned" or "frustrated." Overall, 91% of men reported they would like to test again.

CONCLUSIONS

The Trak System provides a simple and potentially cost-effective means of measuring important semen parameters and may be useful in population-based epidemiologic fertility studies.

Changes in Behavior with Increasing Pregnancy Attempt Time: A Prospective Cohort Study

BACKGROUND

The extent to which couples change their behaviors with increasing pregnancy attempt time is not well documented.

METHODS

We examined change in selected behaviors over pregnancy attempt time in a North American preconception cohort study. Eligible females were ages 21-45 years and not using fertility treatment. Participants completed baseline and bimonthly follow-up questionnaires for up to 12 months or until pregnancy.

RESULTS

Among 3,339 females attempting pregnancy for 0-1 cycles at enrollment, 250 contributed 12 months of follow-up without conceiving. Comparing behaviors at 12 months versus baseline, weighted for loss-to-follow-up, we observed small-to-moderate reductions in mean caffeine intake (-19.5 mg/day, CI = -32.7, -6.37), alcohol intake (-0.85 drinks/week, CI = -1.28, -0.43), marijuana use (-3.89 percentage points, CI = -7.33, 0.46), and vigorous exercise (-0.68 hours/week, CI = -1.05, -0.31), and a large increase in activities to improve conception chances (e.g., ovulation testing) (21.7 percentage points, CI = 14.8, 28.6). There was little change in mean cigarette smoking (-0.27 percentage points, CI = -1.58, 1.04), perceived stress scale score (-0.04 units, CI = -0.77, 0.69), or other factors (e.g., sugar-sweetened soda intake, moderate exercise, intercourse frequency, and multivitamin use), but some heterogeneity within subgroups (e.g., 31% increased and 32% decreased their perceived stress scores by ≥2 units; 14% reduced their smoking but none increased their smoking by ≥5 cigarettes/day).

CONCLUSIONS

Although many behaviors changed with increasing pregnancy attempt time, mean changes tended to be modest for most variables. The largest differences were observed for the use of caffeine, alcohol, and marijuana, and methods to improve conception chances.

The Effects of E-Cigarette Vapor Components on the Morphology and Function of the Male and Female Reproductive Systems: A Systematic Review

E-cigarettes, a comparatively new phenomenon, are regarded as a safer alternative to conventional cigarettes. They are increasingly popular among adolescents of both sexes, and many smokers use e-cigarettes in their attempts to quit smoking. There is little understanding of the effects of exposure to e-cigarette vapors on human reproductive health, human development, or the functioning of the organs of the male and female reproductive systems. Data on the effects of the exposure were derived mainly from animal studies, and they show that e-cigarettes can affect fertility. Here, we review recent studies on the effects of exposure to e-cigarettes on facets of morphology and function in the male and female reproductive organs. E-cigarettes, even those which are nicotine-free, contain many harmful substances, including endocrine disruptors, which disturb hormonal balance and morphology and the function of the reproductive organs. E-cigarettes cannot be considered a completely healthy alternative to smoking. As is true for smoking, deleterious effects on the human reproductive system from vaping are likely, from the limited evidence to date.

A prospective study of treatments for cervical intraepithelial neoplasia and fecundability

BACKGROUND

Treatments for cervical intraepithelial neoplasia remove precancerous cells from the cervix by excising or ablating the transformation zone. Most studies show no association between cervical intraepithelial neoplasia treatments and fertility outcomes. However, only 2 studies have examined time to pregnancy, both using retrospective study designs, with 1 study showing no association and the other showing a 2-fold increased risk of infertility (time to pregnancy >12 months) following excisional or ablative treatment.

OBJECTIVE

We examined the association between cervical intraepithelial neoplasia treatments and fecundability.

MATERIALS AND METHODS

We analyzed data from Pregnancy Study Online (PRESTO), a prospective cohort study of North American pregnancy planners enrolled during 2013-2019. At baseline, women reported whether they ever had an abnormal Papanicolaou test result, the number of abnormal Papanicolaou test results, and their age at first abnormal Papanicolaou test result. They also reported whether they underwent diagnostic (colposcopy) or treatment (excisional or ablative) procedures, and their age at each procedure. We restricted analyses to 8017 women with 6 or fewer cycles of attempt time at enrollment who reported receiving a Papanicolaou test in the previous 3 years. We estimated fecundability ratios and 95% confidence intervals using proportional probabilities models adjusted for sociodemographics, healthcare use, smoking, number of sexual partners, history of sexually transmitted infections, and human papillomavirus vaccination.

RESULTS

A history of abnormal Papanicolaou test results showed little association with fecundability (fecundability ratio, 1.00; 95% confidence interval, 0.95-1.06). Likewise, receipt of colposcopy or treatment procedures, and time since treatment were not materially associated with fecundability. Results were similar when stratified by age and smoking status.

CONCLUSION

We observed no appreciable association of self-reported history of abnormal Papanicolaou test results, colposcopy, treatments for cervical intraepithelial neoplasia, or recency of treatment with fecundability. These results agree with the majority of previous studies in indicating little effect of cervical intraepithelial neoplasia treatments on future fertility.

Tobacco consumption is associated with slow-growing day-6 blastocysts

Objective

To investigate if there are any obvious clinical factors associated with delayed blastulation at day 6 (D6) compared with day 5 (D5).

Design

Monocentric observational cohort study from November 2012 to December 2018.

Setting

Tertiary-care academic medical center.

Patient(s)

A total of 941 women with an entire cohort of exclusively D5 blastocysts compared with 162 patients with a cohort of exclusively D6 blastocysts.

Intervention(s)

None.

Main Outcome Measure(s)

Clinical characteristics and data related to the ovarian stimulation protocols.

Result(s)

After univariate analysis, a significantly higher proportion of women who were active smokers was found in the D6 group compared with the D5 group (n = 22/162 [13.6%] vs. n = 82/941 [8.7%]). In addition, the women in the D6 group had a higher rank number of assisted reproductive technology (ART; total no. of ART cycles performed: 2.1 ± 1.4 vs. 1.6 ± 1.1) and a lower antral follicle count (AFC; 18.7 ± 11.3 vs. 22.2 ± 12.8). Moreover, fertilization with the use of intracytoplasmic sperm injection was used more frequently in the D6 group compared with the D5 group. Logistic regression analysis adjusted for confounders highlighted several independent predictors for reaching blastocyst stage at D6 rather than D5: being an active smoker, previous ART cycles, and a lower AFC.

Conclusion(s)

Obtaining an exclusively D6 blastocyst cohort is independently associated with women who are active smokers, previous ART cycles, and a lower AFC. These findings provide evidence, to be confirmed by further studies, that women who are active smokers could greatly benefit from smoking cessation before undergoing ART.

The Relationship Between Widespread Pollution Exposure and Oxidized Products of Nucleic Acids in Seminal Plasma and Urine in Males Attending a Fertility Center

Background: In recent decades, there has been an increase in male infertility, and in many cases, the etiology remains unclear. Several studies relate male hypo-fertility to xenobiotic exposure, even if no data exist about multiple exposure at the environmental level. Methods: The study involved 86 males with diagnosis of idiopathic male infertility (IMI), and 46 controls with no alteration in sperm characteristics. Seminal plasma (SP) and urine samples were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) to quantify biomarkers of exposure (the main metabolites of benzene, toluene, 1,3-butadiene, 3-monochloropropanediol, styrene, and naphthol) and effect (oxidized products of nucleic acids).Results: Biomarker concentrations were similar in subjects with IMI and controls even if a stronger correlation between biomarkers of exposure and effects were observed in SP. Data show that, both in SP and urine, most metabolites were inter-correlated, indicating a simultaneous co-exposure to the selected substances at the environmental level. Principal component analysis showed in SP the clustering of mercapturic acids indicating a preferential metabolic pathway with Glutathione (GSH) depletion and, consequently, an increase of oxidative stress. This result was also confirmed by multivariable analysis through the development of explanatory models for oxidized products of nucleic acids. Conclusions: This study highlights how oxidative stress on the male reproductive tract can be associated with a different representation of metabolic pathways making the reproductive tract itself a target organ for different environmental pollutants. Our results demonstrate that SP is a suitable matrix to assess the exposure and evaluate the effects of reproductive toxicants in environmental/occupational medicine. The statistical approach proposed in this work represents a model appropriate to study the relationship between multiple exposure and effect, applicable even to a wider variety of chemicals.

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.

Investigation and management of subfertility

Subfertility affects one in seven couples and is defined as the inability to conceive after 1 year of regular unprotected intercourse. This article describes the initial clinical evaluation and investigation to guide diagnosis and management. The primary assessment of subfertility is to establish the presence of ovulation, normal uterine cavity and patent fallopian tubes in women, and normal semen parameters in men. Ovulation is supported by a history of regular menstrual cycles (21-35 days) and confirmed by a serum progesterone >30 nmol/L during the luteal phase of the menstrual cycle. Common causes of anovulation include polycystic ovary syndrome (PCOS), hypothalamic amenorrhoea (HA) and premature ovarian insufficiency (POI). Tubal patency is assessed by hysterosalpingography, hystero-contrast sonography, or more invasively by laparoscopy and dye test. The presence of clinical or biochemical hyperandrogenism, serum gonadotrophins (luteinising hormone/follicle stimulating hormone) / oestradiol, pelvic ultrasound to assess ovarian morphology / antral follicle count, can help establish the cause of anovulation. Ovulation can be restored in women with PCOS using letrozole (an aromatase inhibitor), clomifene citrate (an oestrogen antagonist) or exogenous gonadotrophin administration. If available, pulsatile gonadotrophin releasing hormone therapy is the preferred option for restoring ovulation in HA. Spermatogenesis can be induced in men with hypogonadotrophic hypogonadism with exogenous gonadotrophins. Unexplained subfertility can be treated with in vitro fertilisation after 2 years of trying to conceive. Involuntary childlessness is associated with significant psychological morbidity; hence, expert assessment and prompt treatment are necessary to support such couples.

The impact of sociodemographic characteristics, lifestyle, work exposure and medical history on semen parameters in young Chinese men: A cross-sectional study

There is an ongoing debate on the declining semen quality, and unfortunately, existing evidence is inconclusive and inconsistence. We evaluated the impact of sociodemographic characteristics, lifestyle, medical history and work exposure on semen quality. Univariate and multivariate analysis was used to investigate the association between different risk factors and semen quality parameters. Total sperm count (p = 0.041), sperm concentration (p = 0.007), normal morphology (p = 0.002), total motility (p = 0.004) and progressive motility (p = 0.009) decreased in men with varicocele. Sperm concentration increased in tea (p = 0.044); progressive and total motility increased in cola (p = 0.018, p = 0.012) consumers. Progressive and total motility decreased in urogenital surgery (p = 0.016, p = 0.014) and infection (p = 0.037, p = 0.022). However, age, coffee and alcohol drinking, physical activities, sleep duration and cell phone use were unrelated to any of semen parameters. Interestingly, semen volume (p < 0.0001), total sperm count (p < 0.0001) and concentration (p < 0.033) increased with longer abstinence period (>5 days); normal morphology (p = 0.013) improved in men with higher body mass index (BMI > 24), curvilinear velocity (p = 0.042) increased with smoking; semen volume (p = 0.050) increased in manual labourers. This study highlights the importance of sociodemographic characteristics, lifestyle, occupational exposure and medical history and provides time trends in semen quality, its clinical importance and direction for further research.