Effect of Air Pollution on Menstrual Cycle Length-A Prognostic Factor of Women's Reproductive Health

Health effects of air pollutant mixtures (volatile organic compounds, particulate matter, sulfur and nitrogen oxides) - a review of the literature

The health risks associated with individual air pollutant exposures have been studied and documented, but in real-life, the population is exposed to a multitude of different substances, designated as mixtures. A body of literature on air pollutants indicated that the next step in air pollution research is investigating pollutant mixtures and their potential impacts on health, as a risk assessment of individual air pollutants may actually underestimate the overall risks. This review aims to synthesize the health effects related to air pollutant mixtures containing selected pollutants such as: volatile organic compounds, particulate matter, sulfur and nitrogen oxides. For this review, the PubMed database was used to search for articles published within the last decade, and we included studies assessing the associations between air pollutant mixtures and health effects. The literature search was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A number of 110 studies were included in the review from which data on pollutant mixtures, health effects, methods used, and primary results were extracted. Our review emphasized that there are a relatively small number of studies addressing the health effects of air pollutants as mixtures and there is a gap in knowledge regarding the health effects associated with these mixtures. Studying the health effects of air pollutant mixtures is challenging due to the complexity of components that mixtures may contain, and the possible interactions these different components may have.

Evidence that the woman's ovarian cycle is driven by an internal circamonthly timing system

The ovarian cycle has a well-established circa-monthly rhythm, but the mechanisms involved in its regularity are unknown. Is the rhythmicity driven by an endogenous clock-like timer or by other internal or external processes? Here, using two large epidemiological datasets (26,912 cycles from 2303 European women and 4786 cycles from 721 North American women), analyzed with time series and circular statistics, we find evidence that the rhythmic characteristics of the menstrual cycle are more likely to be explained by an endogenous clock-like driving mechanism than by any other internal or external process. We also show that the menstrual cycle is weakly but significantly influenced by the 29.5-day lunar cycle and that the phase alignment between the two cycles differs between the European and the North American populations. Given the need to find efficient treatments of subfertility in women, our results should be confirmed in larger populations, and chronobiological approaches to optimize the ovulatory cycle should be evaluated.

Short-term association between air pollution and daily genitourinary disorder admissions in Lanzhou, China

The aim of this study was to determine the relationship between short-term exposure to ambient air pollution and the number of daily hospital admissions for genitourinary disorders in Lanzhou. Hospital admission data and air pollutants, including PM2.5, PM10, SO2, NO2, O38h and CO, were obtained from the period 2013 to 2020. A generalized additive model (GAM) combined with distribution lag nonlinear model (DLNM) based on quasi-Poisson distribution was used by the controlling for trends, weather, weekdays and holidays. Short-term exposure to PM2.5, NO2 and CO increased the risk of genitourinary disorder admissions with RR of 1.0096 (95% CI 1.0002-1.0190), 1.0255 (95% CI 1.0123-1.0389) and 1.0686 (95% CI 1.0083-1.1326), respectively. PM10, O38h and SO2 have no significant effect on genitourinary disorders. PM2.5 and NO2 are more strongly correlated in female and ≥ 65 years patients. CO is more strongly correlated in male and < 65 years patients. PM2.5, NO2 and CO are risk factors for genitourinary morbidity, and public health interventions should be strengthened to protect vulnerable populations.

Air pollution and fecundability in a North American preconception cohort study

BACKGROUND

Animal and epidemiologic studies indicate that air pollution may adversely affect fertility. However, the level of evidence is limited and specific pollutants driving the association are inconsistent across studies.

METHODS

We used data from a web-based preconception cohort study of pregnancy planners enrolled during 2013-2019 (Pregnancy Study Online; PRESTO). Eligible participants self-identified as female, were aged 21-45 years, resided in the United States (U.S.) or Canada, and were trying to conceive without fertility treatments. Participants completed a baseline questionnaire and bi-monthly follow-up questionnaires until conception or 12 months. We analyzed data from 8,747 participants (U.S.: 7,304; Canada: 1,443) who had been trying to conceive for < 12 cycles at enrollment. We estimated residential ambient concentrations of particulate matter < 2.5 µm (PM2.5), nitrogen dioxide (NO2), and ozone (O3) using validated spatiotemporal models specific to each country. We fit country-specific proportional probabilities regression models to estimate the association between annual average, menstrual cycle-specific, and preconception average pollutant concentrations with fecundability, the per-cycle probability of conception. We calculated fecundability ratios (FRs) and 95% confidence intervals (CIs) and adjusted for individual- and neighborhood-level confounders.

RESULTS

In the U.S., the FRs for a 5-µg/m3 increase in annual average, cycle-specific, and preconception average PM2.5 concentrations were 0.94 (95% CI: 0.83, 1.08), 1.00 (95% CI: 0.93, 1.07), and 1.00 (95% CI: 0.93, 1.09), respectively. In Canada, the corresponding FRs were 0.92 (95% CI: 0.74, 1.16), 0.97 (95% CI: 0.87, 1.09), and 0.94 (95% CI: 0.80, 1.09), respectively. Likewise, NO2 and O3 concentrations were not strongly associated with fecundability in either country.

CONCLUSIONS

Neither annual average, menstrual cycle-specific, nor preconception average exposure to ambient PM2.5, NO2, and O3 were appreciably associated with reduced fecundability in this cohort of pregnancy planners.

Exposure to Particulate Matter Air Pollution and Age of Menarche in a Nationwide Cohort of U.S. Girls

BACKGROUND

It remains unclear whether in utero and childhood exposure to air pollution affects pubertal development, particularly age of menarche in girls.

OBJECTIVE

The aim of this study was to determine whether residential ambient particulate matter (PM) exposure in utero and during childhood is associated with age of menarche.

METHODS

We studied 5,201 girls in the Growing Up Today Study 2 (2004-present) who were 10-17 y of age at enrollment (47.7% premenarchal; 52.3% postmenarchal). Exposure to three size fractions of PM [fine PM with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ), PM with aerodynamic diameters between  2.5 μ m  and  10 μ m (PM 2.5 - 10 ), and PM with aerodynamic diameter 10 μ m (PM 10 )] was assigned based on maternal residential address, updated every 2 y, using nationwide spatiotemporal models. We estimated average PM exposure in utero, and time-varying windows: annual average exposure in the prior 1 and 2 y and cumulative average from birth. Age of menarche was self-reported on three surveys administered in 2004, 2006, and 2008. We calculated hazard ratios (HR) for menarche for an interquartile range (IQR) increase in PM exposure using Cox proportional hazard models adjusting for potential confounders.

RESULTS

Girls attained menarche at 12.3 y of age on average. In the adjusted model, higher residential exposure to ambient PM 2.5 during all time windows was associated with earlier age of menarche. The HRs of menarche for each IQR (4   μ g / m 3 ) increase in exposure to PM 2.5 during the in utero period, 1 y prior to menarche, and throughout childhood were 1.03 [95% confidence interval (CI): 1.00, 1.06], 1.06 (95% CI: 1.02, 1.10) and 1.06 (95% CI: 1.02, 1.10), respectively. Effect estimates for PM 10 exposure were similar, albeit attenuated, for all time windows. PM 2.5 - 10 exposure was not associated with age of menarche.

DISCUSSION

Among a large, nationwide, prospective cohort of U.S. girls, higher exposure to PM 2.5 and PM 10 in utero and throughout childhood was associated with an earlier age of menarche. Our results suggest that PM 2.5 and PM 10 may have endocrine-disrupting properties that could lead to altered timing of menarche. https://doi.org/10.1289/EHP12110.

Ultrastructural Evaluation of Mouse Oocytes Exposed In Vitro to Different Concentrations of the Fungicide Mancozeb

Mancozeb is a widely used fungicide, considered to be an endocrine disruptor. In vivo and in vitro studies evidenced its reproductive toxicity on mouse oocytes by altering spindle morphology, impairing oocyte maturation, fertilization, and embryo implantation. Mancozeb also induces dose-dependent toxicity on the ultrastructure of mouse granulosa cells, including chromatin condensation, membrane blebbing, and vacuolization. We evaluated the effects on the ultrastructure of mouse oocytes isolated from cumulus-oocyte complexes (COCs), exposed in vitro to increasing concentrations of mancozeb. COCs were matured in vitro with or without (control) low fungicide concentrations (0.001-1 μg/mL). All mature oocytes were collected and prepared for light and transmission electron microscopy. Results showed a preserved ultrastructure at the lowest doses (0.001-0.01 μg/mL), with evident clusters of round-to-ovoid mitochondria, visible electron-dense round cortical granules, and thin microvilli. Mancozeb concentration of 1 μg/mL affected organelle density concerning controls, with a reduction of mitochondria, appearing moderately vacuolated, cortical granules, and microvilli, short and less abundant. In summary, ultrastructural data revealed changes mainly at the highest concentration of mancozeb on mouse oocytes. This could be responsible for the previously described impaired capability in oocyte maturation, fertilization, and embryo implantation, demonstrating its impact on the reproductive health and fertility.

Effects of Exposure Duration and Exposure Levels of Ambient Air Pollutants on the Risk of Polycystic Ovarian Syndrome: A 2015-2019 Korean Population-Based Cohort Study

Exposure to ambient air pollution is associated with an increased risk of menstrual disorders and infertility. This study examined the relationships between the levels and duration of air pollution exposure and the risk of polycystic ovarian syndrome (PCOS) using Korean population-based cohort data (2015-2019). Real-time data on PM₁₀, PM_2.5, O₃, CO, SO₂, and NO₂ were provided by the Korean Ministry of Environment. The average monthly air pollutant concentration from 1 January 2014 to 31 December 2018 was analyzed. To assess individual-level exposure to air pollutants, a spatial prediction model and an area-averaging approach were used. In total, 237,582 PCOS cases were analyzed. The annual age-adjusted PCOS incidence was 6.70, 8.28, 9.73, 11.58, and 11.97% from 2015-2019, respectively. The PCOS risk increased 1.29-1.32, 1.43-1.52, and 1.32-fold following exposure to the 2-year and 3-year average levels of PM_2.5, O₃, and NO₂, respectively, compared to their 1-year average levels. The PCOS risk increased 1.75-fold (95% confidence interval: 1.66-1.85) in the fourth-quartile for the NO₂ level. Increased SO₂ and CO levels in the second- and third-quartiles were also associated with an increased PCOS risk. Exposure to air pollutants thus increased the risk for PCOS in the Korean population.

Toxicological Effects of Technical Xylene Mixtures on the Female Reproductive System: A Systematic Review

Technical xylene is a compound of massive production that is used in applications such as petrochemical and healthcare laboratories. Exposure to xylene can cause acute and chronic effects in humans and animals. Currently available studies regarding xylene’s adverse effects with credible designs were dated almost twenty years ago. This systematic review summarizes the findings regarding the detrimental effects of technical xylene from human, animal, and in vitro studies. It recapitulated available studies with respect to the effects of xylene on the female reproductive system to stress the need for updating the current data and guidelines. Based on pre-specified criteria, 22 studies from journal databases exploring the toxic effects of xylene on menstruation, endocrine endpoints, fetal development, and reproductive functions were included for the review. It was found that related studies with a specific focus on the effects of technical xylene on the female reproductive system were insufficient. Therefore, further studies are necessary to update the existing data, thus improving the quality and reliability of risk assessment of exposure to xylene in pregnant women

Ambient air pollution on fecundity and live birth in women undergoing assisted reproductive technology in the Yangtze River Delta of China

BACKGROUND

Ambient air pollution has adverse effects on the reproductive system. However, inconsistent conclusions were reached from different studies with regard to air pollutants and pregnancy outcomes, especially the livebirth rate in assisted reproductive technology (ART) in different windows of exposure.

METHODS

A retrospective cohort study was conducted on 12,665 women who underwent first fresh or frozen embryo transfer cycle in the Yangtze River Delta of China. Daily average levels of six air pollutants in four different periods were obtained: Period 1 and 2: 90 days or one year prior to oocyte retrieval; Period 3 and 4: the day of oocyte retrieval or one year prior to oocyte retrieval to the day of serum hCG test or to the end of the pregnancy. A multiple logistic regression model was used to investigate the association between air pollutant exposure and pregnancy outcomes. Stratified analyses were conducted to explore potential modifier effects.

RESULTS

The one year exposure window (Period 2) before oocyte retrieval had a more evident negative association with pregnancy outcomes. Each IQR increase in ambient PM10 (OR: 0.89, 95% CI: 0.84-0.93), PM2.5 (OR: 0.82, 95% CI: 0.77-0.87), SO2 (OR: 0.87, 95% CI: 0.83-0.91) and CO (OR: 0.91, 95% CI: 0.87-0.96) was associated with a respective 11%, 18%, 13% and 9% decrease in the likelihood of live birth. In entire exposure window of Period 4, all air pollutants except for O3 were associated with a decreased likelihood of live birth. Stratified analyses showed that women undergoing frozen embryo transfer cycles, especially those with two embryos transferred, were more vulnerable to air pollutant exposure.

CONCLUSION

This study indicates a negative association between air pollutant exposure before oocyte retrieval and livebirth rate in ART. The adverse impact was more evident in one year exposure compared to three-month refresh cycle of the gametes. Additional protection from air pollution should be undertaken at least one year before ART, particularly for those with frozen embryo transfer cycles.

Effect of air pollution on age at menarche in polish females, born 1993-1998

The aim of the study was to analyse the association between the degree of air pollution (suspended particulate matter, sulphur dioxide, benzopyrene levels) in the location of residence during childhood and adolescence and the age at menarche. The research was carried out in the period from 2015 to 2018 in Poland. Anthropometric measurements were performed, and questionnaire data were collected from 1,257 women, aged 19-25 years. The average levels of subjects' exposure to analysed air pollutants, i.e., particulate matter, sulphur dioxide, nitric oxide and benzene during childhood-adolescence was assessed from the data acquired by the Polish Chief Inspectorate for Environmental Protection. Negative relationships between age at menarche and suspended particulate matter as well as nitrogen levels were found. A similar trend was observed in an analysis of the relationship between age at menarche and the complex air pollution index. The tendency for age at menarche to decrease together with worsening air quality was also visible after adjusted for socioeconomic status. Girls exposed to high suspended particulate matter levels were characterised by higher risk of early age at menarche. High levels of air pollution are related to younger age at menarche and the risk of the menstruation onset below 11 years.

Fine particulate matter and polycystic ovarian morphology

BACKGROUND

Polycystic ovary morphology (PCOM) is an ultrasonographic finding that can be present in women with ovulatory disorder and oligomenorrhea due to hypothalamic, pituitary, and ovarian dysfunction. While air pollution has emerged as a possible disrupter of hormone homeostasis, limited research has been conducted on the association between air pollution and PCOM.

METHODS

We conducted a longitudinal cohort study using electronic medical records data of 5,492 women with normal ovaries at the first ultrasound that underwent a repeated pelvic ultrasound examination during the study period (2004-2016) at Boston Medical Center. Machine learning text algorithms classified PCOM by ultrasound. We used geocoded home address to determine the ambient annual average PM2.5 exposures and categorized into tertiles of exposure. We used Cox Proportional Hazards models on complete data (n = 3,994), adjusting for covariates, and additionally stratified by race/ethnicity and body mass index (BMI).

RESULTS

Cumulative exposure to PM2.5 during the study ranged from 4.9 to 17.5 µg/m3 (mean = 10.0 μg/m3). On average, women were 31 years old and 58% were Black/African American. Hazard ratios and 95% confidence intervals (CI) comparing the second and third PM2.5 exposure tertile vs. the reference tertile were 1.12 (0.88, 1.43) and 0.89 (0.62, 1.28), respectively. No appreciable differences were observed across race/ethnicity. Among women with BMI ≥ 30 kg/m2, we observed weak inverse associations with PCOM for the second (HR: 0.93, 95% CI: 0.66, 1.33) and third tertiles (HR: 0.89, 95% CI: 0.50, 1.57).

CONCLUSIONS

In this study of reproductive-aged women, we observed little association between PM2.5 concentrations and PCOM incidence. No dose response relationships were observed nor were estimates appreciably different across race/ethnicity within this clinically sourced cohort.

Joint effect of particulate matter and cigarette smoke on women's sex hormones

BACKGROUND

Although relationships between exposure to air pollution and reproductive health are broadly studied, mechanisms behind these phenomena are still unknown. The aim of the study was to assess whether exposure to particulate matter (PM10) and tobacco smoking have an impact on menstrual profiles of 17β-estradiol (E2) and progesterone (P) and the E2/P ratio.

METHODS

Levels of sex hormones were measured daily in saliva during the entire menstrual cycle among 132 healthy, urban women. Exposure to smoking (active or passive) was assessed by questionnaire, whilst exposure to PM10 with municipal monitoring data.

RESULTS

During the early luteal phase, profiles of E2 were elevated among women with higher versus lower exposure to PM10 (p = 0.02, post-hoc tests). Among those who were exposed versus unexposed to tobacco smoking, the levels of mean E2 measured during the entire cycle were higher (p = 0.02). The difference in mean E2 levels between the group of joint exposure (i.e. to high PM10 and passive or active smoking) versus the reference group (low PM10, no smoking) was statistically significant at p = 0.03 (18.4 vs. 12.4 pmol/l, respectively). The E2/P ratios were higher among women with higher versus lower exposure to PM10 and this difference was seen only in the early luteal phase (p = 0.01, exploratory post-hoc tests).

CONCLUSIONS

We found that PM10 and tobacco smoking affect ovarian hormones independently and do not interact with each other. Both exposures appear to have estrogenic effects even though women's susceptibility to these effects differs across the menstrual cycle. We propose that the hormonal mechanisms are involved in observed relationships between air pollution and smoking with women's reproductive health.

Air pollution increased risk of reproductive system diseases: a 5-year outcome analysis of different pollutants in different seasons, ages, and genders

Air pollution remains a serious environmental problem worldwide, and the effects of air pollutants with reproductive system diseases have already attracted extensive attention. The present study investigated the risk of air pollutants on reproductive system diseases, based on daily medical visits (DMV) of the past 5 years in central China. Data of DMV outpatients with reproductive system diseases were obtained from a general hospital in Zhengzhou, October 28, 2013 to May 31, 2018, as well as atmospheric pollutants data. Correlation of air pollutants and DMV was analyzed with distributed lag nonlinear model (DLNM), including total cases of reproductive system diseases, and in different seasons (spring, summer, autumn, and winter), genders (male and female), and age groups (<26, 26-35, and >35 years old). A total of 374,558 visits were included. NO2 was most closely relevant to incidence risk of total cases analysis with each increased interquartile ranges (IQRs) in the 6 pollutants, with 30-day lag. Relationship to pollutants was more sensitive in fall, >35 years old, and male groups than in other seasons, ages, and females, and NO2 had the highest risk on reproductive diseases. Air pollution increased risk of reproductive system diseases, and different pollutants played different roles in different seasons, ages, and genders. The results of this study will provide evidence for effective air quality controlling and human reproductive protection.

Menstrual cycle length and modern living: a review

PURPOSE OF REVIEW

The aim of this review is to evaluate biological, life history, environmental, and lifestyle factors and exposures that cause variability in menstrual cycle length (MCL).

RECENT FINDINGS

Recent literature has detailed a number of factors that influence MCL, with particular emphasis placed on novel environmental exposures, such as air pollution and endocrine disrupting chemicals.

SUMMARY

MCL varies widely in response to intrinsic and extrinsic inputs and is a useful predictor of reproductive health and fecundability.

VIDEO ABSTRACT

http://links.lww.com/COE/A28.

Could Kallikrein-Related Serine Peptidase 3 Be an Early Biomarker of Environmental Exposure in Young Women?

Bisphenols and phthalates affect androgen receptor-mediated signaling that directly regulates Kallikrein-Related serine Peptidase 3 (KLK3) secretion, indicating that environmental factors may play a role in KLK3 secretion. With the aim of obtaining preliminary data on whether KLK3 could serve as an early marker of environmental pollution effects, in 61 and 58 healthy women living in a high environmental impact (HEI) and low environmental impact (LEI) area, respectively, serum KLK3 levels at different phases of menstrual cycle were measured. KLK3 values resulted in always being higher in the HEI group with respect to the LEI group. These differences were particularly relevant in the ovulatory phase (cycle day 12°–13°) of the menstrual cycle. The differences in KLK3 values during the three phases of the menstrual cycle were significant in the LEI group differently from the HEI group. In addition, higher progesterone levels were observed in the LEI group with respect to the HEI group in the luteal phase, indicating an opposite trend of KLK3 and progesterone in this phase of the menstrual cycle. Although changes in KLK3 could also depend on other factors, these preliminary data could be an early indication of an expanding study of the role of biomarkers in assessing early environmental effects for female reproductive health.

Association between exposure to ambient air pollutants and the outcomes of in vitro fertilization treatment: A multicenter retrospective study

BACKGROUND

Exposure to ambient air pollution has been reported to be inversely correlated with human reproductive health. However, the results of previous studies exploring the association between air pollution and in vitro fertilization (IVF) outcomes are conflicting, and further research is needed to clarify this association.

OBJECTIVES

This study aimed to investigate the associations between exposure to air pollutants and IVF outcomes.

METHODS

We conducted a multicenter retrospective cohort study involving 20,835 patients from four cities in Northern China, contributing to 11,787 fresh embryo transfer cycles, 9050 freeze-all cycles, and 17,676 frozen-thawed embryo transfer (FET) cycles during 2014-2018. We calculated the daily average concentrations of six criteria air pollutants (PM_2.5, PM₁₀, O₃, NO₂, CO, and SO₂) during different exposure windows in IVF treatment timeline using data from the air monitoring station nearest to the residential site as approximate individual exposure. Generalized estimation equation models were used to assess the association between air pollution exposure and IVF outcomes.

RESULTS

Exposure to O₃, NO₂, and CO during most exposure windows in fresh embryo transfer cycles were correlated with lower possibilities of biochemical pregnancy, clinical pregnancy, and live birth. An inverse association of exposure to O₃ and SO₂ with pregnancy outcomes was observed in FET cycles. In addition, we found a significant association of exposure to air pollutants with a higher risk of ectopic pregnancy and lower oocyte yield.

CONCLUSIONS

Our study provided large-scale human evidence of the association between air pollution and adverse human reproductive outcomes in the population opting for IVF. Thus, exposure to air pollutants in the population opting for IVF should be limited to improve treatment outcomes.

The Specificities of Elite Female Athletes: A Multidisciplinary Approach

Female athletes have garnered considerable attention in the last few years as more and more women participate in sports events. However, despite the well-known repercussions of female sex hormones, few studies have investigated the specificities of elite female athletes. In this review, we present the current but still limited data on how normal menstrual phases, altered menstrual phases, and hormonal contraception affect both physical and cognitive performances in these elite athletes. To examine the implicated mechanisms, as well as the potential performances and health risks in this population, we then take a broader multidisciplinary approach and report on the causal/reciprocal relationships between hormonal status and mental and physical health in young (18-40 years) healthy females, both trained and untrained. We thus cover the research on both physiological and psychological variables, as well as on the Athlete Biological Passport used for anti-doping purposes. We consider the fairly frequent discrepancies and summarize the current knowledge in this new field of interest. Last, we conclude with some practical guidelines for eliciting improvements in physical and cognitive performance while minimizing the health risks for female athletes.

Increased Incidence of Dysmenorrhea in Women Exposed to Higher Concentrations of NO, NO2, NOx, CO, and PM2.5: A Nationwide Population-Based Study

Background: Air pollution is speculated to affect the reproductive health of women. However, a longitudinal association between exposure to air pollution and dysmenorrhea has not been identified, which this study aimed to examine this point.

Methods: Two nationwide databases, namely the Taiwan Air Quality Monitoring database and the Taiwan National Health Research Institutes database were linked. Women with a history of dysmenorrhea (International Classification of Disease, Ninth Revision, Clinical Modification code 625.3) before 2000 were excluded. All participants were followed from January 1, 2000 until the diagnosis of dysmenorrhea, withdrawal from National Health Insurance, or December 31, 2013. Furthermore, air pollutants were categorized into quartiles with three cut-off points (25th, 50th, and 75th percentiles). The Cox regression model was used to calculate the hazard ratios of dysmenorrhea.

Results: This study enrolled 296,078 women. The mean concentrations of yearly air pollutants were 28.2 (±12.6) ppb for nitric oxides (NO_x), 8.91 (±7.93) ppb for nitric oxide (NO), 19.3 (±5.49) ppb for nitrogen dioxide (NO₂), 0.54 (±0.18) ppm for carbon monoxide (CO), and 31.8 (±6.80) μg/m³ for PM_2.5. In total, 12,514 individuals developed dysmenorrhea during the 12-year follow-up. Relative to women exposed to Q1 concentrations of NO_x, women exposed to Q4 concentrations exhibited a significantly higher dysmenorrhea risk [adjusted hazard ratio (aHR)= 27.9, 95% confidence interval (CI) = 21.6–31.3]; similarly higher risk was found for exposure to NO (aHR = 16.7, 95% CI = 15.4–18.4) and NO₂ (aHR = 33.1, 95% CI = 30.9–37.4). For CO, the relative dysmenorrhea risk in women with Q4 level exposure was 28.7 (95% CI = 25.4–33.6). For PM_2.5, women at the Q4 exposure level were 27.6 times (95% CI = 23.1–29.1) more likely to develop dysmenorrhea than those at the Q1 exposure level.

Conclusion: Our results showed that women would have higher dysmenorrhea incidences while exposure to high concentrations of NO, NO₂, NO_x, CO, and PM_2.5.

Climate change and declining fertility rate in Malaysia: the possible connexions

Climate change is an incessant global phenomenon and has turned contentious in the present century. Malaysia, a developing Asian country, has also undergone significant vicissitudes in climate, which has been projected with significant deviations in forthcoming decades. As per the available studies, climate changes may impact on the fertility, either via direct effects on the gonadal functions and neuroendocrine regulations or via several indirect effects on health, socioeconomic status, demeaning the quality of food and water. Malaysia is already observing a declining trend in the Total fertility rate (TFR) over the past few decades and is currently recorded below the replacement level of 2.1 which is insufficient to replace the present population. Moreover, climate changes reportedly play a role in the emergence and cessation of various infectious diseases. Besides its immediate effects, the long-term effects on health and fertility await to be unveiled. Despite the huge magnitude of the repercussion of climate changes in Malaysia, research that can explain the exact cause of the present reduction in fertility parameters in Malaysia or any measures to preserve the national population is surprisingly very scarce. Thus, the present review aims to elucidate the possible missing links by which climate changes are impairing fertility status in Malaysia.

Environmental toxicant exposure and menstrual cycle length

PURPOSE OF REVIEW

This review seeks to evaluate the impact of environmental exposures on the menstrual cycle length detailing timing of exposure on pathophysiology.

RECENT FINDINGS

Recent literature has examined the relationship between menstrual cycle length and environmental exposures including air pollutants, parabens, and polybrominated biphenyls.

SUMMARY

Research is limited but suggest importance of further research in evaluating environmental exposures and menstrual cycle length.

Associations between childhood and adolescence exposure to air pollution and adult height in polish women

Exposure to airborne substances harmful to health during pre- and postnatal stage may significantly affect the correct development of organs and systems. Many studies analyze the relationship between air quality and health, but data on the impact of air pollution on human biological development are scanty. The aim of the study was to assess the relationships between adult body height and air quality in the place of residence during childhood and adolescence. The parameters measured included absolute stature (cm) and relative stature defined as a percentage of mean stature of both parents. The analysis covered data collected from 1257 women. Subject's height was measured. Data on parental height were obtained using a questionnaire. The level of each analysed environmental pollution in the place of residence during childhood and adolescence: particulate matter (PM₁₀, PM_2.5)_, sulphur dioxide (SO₂)_, nitric dioxide (NO₂) and benzene (C₆H₆) in the place of residence during childhood and adolescence was determined on the basis of the data made available by the Polish Chief Inspectorate for Environmental Protection. Results of our study show that mean stature decreases with growing air pollution level. Significant differences were observed both in absolute stature and relative stature (expressed as percentage of mean stature of both parents) depending on PM₁₀ and PM_2.5 levels in place of residence during childhood and adolescence as well as on the total index of air quality. The differences remain statistically significant also after adjustment for the degree of urbanisation of the place of residence and factors related to socio-economic status. Our findings suggest that air pollution level in the place of residence during childhood and adolescence has significant impact on the children growth, potentially leading to worse health status later in life.

Ovarian Dysfunction Induced by Chronic Whole-Body PM2.5 Exposure

Fine particulate matter (PM2.5) pollution arouses public health concerns over the world. Increasing epidemiologic evidence suggests that exposure to ambient airborne PM2.5 increases the risk of female infertility. However, relatively few studies have systematically explored the harmful effect of chronic PM2.5 exposure on ovarian function and the underlying mechanisms. In this study, female C57BL/6J mice are exposed to filtered air or urban airborne PM2.5 for 4 months through a whole-body exposure system. It is found that PM2.5 exposure significantly caused the alteration of estrus cycles, reproductivity, hormone levels, and ovarian reserve. The granulosa cell apoptosis via the mitochondria dependent pathway contributes to the follicle atresia. With RNA-sequencing technique, the differentially expressed genes induced by PM2.5 exposure are mainly enriched in ovarian steroidogenesis, reactive oxygen species and oxidative phosphorylation pathways. Furthermore, it is found that increased PM2.5 profoundly exacerbated ovarian oxidative stress and inflammation in mice through the NF-κB/IL-6 signaling pathway. Notably, dietary polydatin (PD) supplement has protective effect in mice against PM2.5-induced ovarian dysfunction.These striking findings demonstrate that PM2.5 and/or air pollution is a critical factor for ovarian dysfunction through mitochondria-dependent and NF-κB/IL-6-mediated pathway, and PD may serve as a pharmaceutic candidate for air pollution-associated ovarian dysfunction.

Association between Female Reproductive Health and Mancozeb: Systematic Review of Experimental Models

Mancozeb is a widely used fungicide approved for use in agriculture in many countries with long persistence in the environment and consequent bioaccumulation in tissues and biological fluids. Despite the large amount of studies published in recent years, the relationship between mancozeb exposure and female reproductive health is not fully elucidated. In order to summarize current evidence on mancozeb exposure and female reproductive disease, we performed a systematic review of literature. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to make this review. An adapted version of the National Toxicology Program’s Office of Health and Assessment and Translation (OHAT) framework was used to evaluate the risk of bias. Electronic search on two databases (PubMed and Scopus) was used to find experimental studies (in vitro and in vivo) on mancozeb exposure. The database search identified 250 scientific articles, 20 of which met our inclusion criteria. Selected data were then reviewed and summarized in tables. Overall, mancozeb represents a hazard for female reproductive health, with different mechanisms of action. Undoubtedly more experimental and epidemiological studies are required to definitively validate mancozeb as reproductive toxicant.

Association between air pollution and menstrual disorder outpatient visits: A time-series analysis

Menstrual disorders are common diseases among reproductive-aged women with increasing concerns. Until now, there have been limited studies about the association between menstrual disorders and air pollution. This study aimed to investigate the association between short-term (concurrent day and within 1 week prior) ambient air pollution exposure and menstrual disorder outpatient visits in Xi'an, a metropolis in northwestern China. Daily baseline outpatient data of menstrual disorders from January 1, 2010 to February 18, 2016 (2239 days) were obtained. An over-dispersed Poisson generalized additive model was applied to discover the relationship between short-term air pollution exposure and the number of menstrual disorder outpatient visits by adjusting the day of the week and weather conditions. A total of 51,893 outpatient visits for menstrual disorders were recorded. A 10 μg/m³ increase of PM₁₀ and NO₂ concentrations corresponded to 0.236% (95% Cl: 0.075%, 0.397%) and 2.173% (95% Cl: 0.990%, 3.357%) elevations in outpatient-visits for menstrual disorders at lag 7 and lag 01 (concurrent day and previous 1 day), respectively. The association was more significant in young females (18-29 years) and there was no obvious association observed between SO₂ and menstrual disorder outpatient visits. This is the first evidence that short-term exposure to ambient air pollution can be associated with an increased risk of menstrual disorder attacks. The results of our study may help to establish more comprehensive understanding of the health effects of ambient air pollution on menstrual disorders and other reproductive diseases.

Can atmospheric pollutants influence menstrual cycle function?

A few experimental studies suggest that atmospheric pollutants could affect the endocrine system, and in particular stress hormones and the hypothalamic-hypophyseal-ovarian axis, which could in turn influence menstrual cycle function. We aimed to study the possible short-term effects of atmospheric pollutants on the length of the follicular and luteal phases and on the duration of the menstrual cycle in humans. To do so, from a nation-wide study on couples' fecundity, we recruited 184 women not using contraception who collected urine samples at least every other day during one menstrual cycle, from which a progesterone metabolite was assayed, allowing estimation of the duration of the follicular and luteal phases of the cycle. Atmospheric pollution (nitrogen dioxide and particulate matter with an aerodynamical diameter below 10 μm, PM₁₀) levels were estimated from a dispersion model with a 1-km resolution combined with permanent monitoring stations measurements, allowing to estimate exposures in the 30-day, 1-10 and 11-30-day periods before the start of the menstrual cycle. Regression models allowed to quantify the change in cycle duration associated with atmospheric pollutants and adjusted for potential confounders. Follicular phase duration increased on average by 0.7 day (95% confidence interval, CI, 0.2; 1.3) for each increase by 10 μg/m³ in NO₂ concentration averaged over the 30 days before the cycle and by 1.6 day (95% CI, 0.3; 2.9) for each increase by 10 μg/m³ in PM₁₀. There was no strong evidence of associations of exposures in this time window with luteal phase or with total menstrual cycle durations (p > 0.2). Exposures in the 1-10 day period before the cycle start were also associated with increased follicular phase duration. This study is one of the first prospective studies to suggest short-term alterations in follicular phase duration following atmospheric pollutants exposure.

Socioeconomic factors and lifestyle affecting the variability of menstrual cycle characteristics in women from Central Poland

Regularity, length of the cycle and duration of menstrual flow are a reflection of women health. The purpose of the research was to assess the relationships between socioeconomic status, cycle length, duration of menses, regularity and dysmenorrhea. A survey was conducted among 896 healthy women from Łódź and Warsaw (Poland), aged 15.71–26.98. Women who were menarche at least 3 years ago were asked to complete the survey. Women were asked about cycle length (number of days), duration of menstrual flow, regularity of the cycle, dysmenorrhea, birth place, parental education level, attendance at physical education classes, participation in additional sports activities, self-assessment of stress levels at home and at school/university, and smoking. For data analysis, t-test, analysis of variance, and chi-square were used, and p<0.05 was considered to be statistically significant. There were no significant relationships between the mean cycle length, regularity and the environmental factors, except for differences in the average length of the menstrual cycle in women from Łódź who attend additional sports activities. Women who are more physically active are characterized by a shorter menstrual cycle. In terms of the length of the menstrual flow, daughters of better educated fathers were characterized by longer menses. In contrast, dysmenorrhea was associated with longer menstrual periods and longer menstrual bleeding, as well as with higher levels of stress, both at home and at school. Environmental factors affected the features of menstruation cycles in women from Central Poland.

The Impacts of Different Air Pollutants on Domestic and Inbound Tourism in China

Previous studies have reported that air pollution negatively affects the tourism industry. This paper attempted to answer the following question: among different air pollutants, which one acts as the most adverse factor? The study was based on a sample of panel data covering 337 Chinese cities for the period between 2007 and 2016. Four pollutant indicators were inspected: PM 2 . 5 (particulate matter 2.5 micrometers or less in size), PM 10 (particulate matter 10 micrometers or less in size), SO 2 (sulfur dioxide), and NO 2 (nitrogen dioxide). It was found that PM 2 . 5 had a significantly negative impact on both domestic and inbound tourist arrivals. Regarding the other three pollutant indicators, except for the negative influence of NO 2 on inbound tourist arrivals, no statistically significant impact was found. This study suggests that tourism policy makers should primarily focus on PM 2 . 5 , when considering the nexus between air quality and tourism development. According to our estimates, the negative impact of PM 2 . 5 on tourism is substantial. If the PM 2 . 5 concentration in the ambient air increases by 1 μ g/m 3 (=0.001 mg/m 3 ), domestic and inbound tourist arrivals will decline by 0.482% and 1.227%, respectively. These numbers imply an average reduction of 81,855 person-times in annual domestic tourist arrivals and 12,269 in inbound tourist arrivals in each city.

Characteristics of patients with endometrial hyperplasia under different air quality index conditions

OBJECTIVE

Air pollution has been widely recognized to pose a threat to health. Urban outdoor air pollution was listed as the 14th biggest risk factor for global deaths in 2004 in the Global Health Risks report published by the World Health Organization in 2009. Many past studies have indicated that exposure to environmental contaminants promotes changes in the internal mechanisms of diseases, including the infection of various systems in the body, hormonal changes, and vascular proliferation. These changes may be related to the severity of endometrial hyperplasia. Therefore, this study used the air quality monitoring data of the Environmental Protection Administration (EPA) to examine the effects of air pollutant concentration on patients with endometrial hyperplasia.

MATERIALS AND METHODS

This population-based nationwide study used data for 2002-2013 from the National Health Insurance Research Database of Taiwan. Patients who developed endometrial hyperplasia before 2002 were excluded. In total, 14,883 patients with endometrial hyperplasia were tracked. The exposure levels and air quality index (AQI) values in this study were based on the taiwan air quality monitoring network data collected by the EPA from 2000 to 2013. The data were further divided into the good air quality group (AQI ≤ 50) and poor air quality group (AQI > 50). The study used linear regression model to estimate the correlation linking air pollutant concentration with endometrial hyperplasia.

RESULTS

The results indicated that, in comparison to endometrial hyperplasia patients who were exposed to air with good quality, those exposed to air with poor quality had a higher average age (p < 0.001) and higher proportion of living in southern Taiwan (p < 0.001), as well as higher rates of diabetes (p < 0.001), hyperlipidemia (p < 0.001), hypertension, cerebrovascular diseases (p = 0.024), cerebral vascular accidents (p = 0.024), and chronic kidney disease (p < 0.001).

CONCLUSION

The patients with endometrial hyperplasia in poor AQI area had severe comorbidity. Thus, attention must be paid to the improvement of air quality and the implementation of preventive measures against contaminants.

Hormonal Predictors of Abnormal Luteal Phases in Normally Cycling Women

Objective: Explore potential relationships between preovulatory, periovulatory, and luteal-phase characteristics in normally cycling women.

Design: Observational study.

Setting: Eight European natural family planning clinics.

Patient(s): Ninety-nine women contributing 266 menstrual cycles.

Intervention(s): The participants collected first morning urine samples that were analyzed for estrone-3 glucuronide (E1G), pregnanediol-3- alpha-glucuronide (PDG), follicle stimulating hormone (FSH), and luteinizing hormone (LH). The participants underwent serial ovarian ultrasound examinations.

Main Outcome Measure(s): Four outcome measures were analyzed: short luteal phase, low mid-luteal phase PDG level (mPDG), normal then low luteal PDG level, low then normal luteal PDG level.

Results: A long preovulatory phase was a predictor of short luteal phase, with or without adjustment for other variables. A high periovulatory PDG level was a predictor for short luteal phase as well as normal then low luteal PDG level. A low periovulatory PDG level predicted low mPDG and low then normal luteal PDG level, with or without adjustment for other variables. A small maximum follicle predicted normal then low luteal PDG level, with or without adjustment for other variables. The relationship between small maximum follicle size and short luteal phase or small maximum follicle size and low mPDG was no longer present when the regression was adjusted for certain characteristics. A younger age at menarche and a high body mass index were both predictors of low mPDG.

Conclusion: Luteal phase abnormalities exist over a spectrum where some ovulation disorders may exist as deviations from the normal ovulatory process.This study confirms the negative impact of a small follicle size on the quality of the luteal phase. The occurrence of normal then low luteal PDG level is confirmed as a potential sign of luteal phase abnormality.