A prospective cohort study of ambient air pollution exposure and risk of uterine leiomyomata

Outdoor air pollution exposure and uterine cancer incidence in the Sister Study

BACKGROUND

Outdoor air pollution is a ubiquitous exposure that includes endocrine-disrupting and carcinogenic compounds that may contribute to the risk of hormone-sensitive outcomes such as uterine cancer. However, there is limited evidence about the relationship between outdoor air pollution and uterine cancer incidence.

METHODS

We investigated the associations of residential exposure to particulate matter less than 2.5 µm in aerodynamic diameter (PM2.5) and nitrogen dioxide (NO2) with uterine cancer among 33 417 Sister Study participants with an intact uterus at baseline (2003-2009). Annual average air pollutant concentrations were estimated at participants' geocoded primary residential addresses using validated spatiotemporal models. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals for the association between time-varying 12-month PM2.5 (µg/m3) and NO2 (parts per billion; ppb) averages and uterine cancer incidence.

RESULTS

Over a median follow-up period of 9.8 years, 319 incident uterine cancer cases were identified. A 5-ppb increase in NO2 was associated with a 23% higher incidence of uterine cancer (hazard ratio = 1.23, 95% confidence interval = 1.04 to 1.46), especially among participants living in urban areas (hazard ratio = 1.53, 95% confidence interval = 1.13 to 2.07), but  PM2.5 was not associated with increased uterine cancer incidence.

CONCLUSION

In this large US cohort, NO2, a marker of vehicular traffic exposure, was associated with a higher incidence of uterine cancer. These findings expand the scope of health effects associated with air pollution, supporting the need for policy and other interventions designed to reduce air pollutant exposure.

Exposure to urban ambient particles (PM2.5) before pregnancy affects the expression of endometrial receptive markers to embryo implantation in mice: Preliminary results

Air pollution (AP) is one of the main recent concerns in reproductive healthy due to its potential to promote negative outcomes during pregnancy and male and female fertility. Several studies have demonstrated that AP exposure has been linked to increased embryonic implantation failures, alterations in embryonic, fetal and placental development. For a well-succeeded implantation, both competent blastocyst and receptive endometrium are required. Based on the lack of data about the effect of AP in endometrial receptivity, this study aimed to evaluate he particulate matter (PM) exposure impact on uterine receptive markers in mice and associate the alterations to increased implantation failures due to AP. For this study, ten dams per group were exposed for 39 days to either filter (F) or polluted air (CAP). At fourth gestational day (GD4), females were euthanized. Morphological, ultrastructural, immunohistochemical and molecular analysis of uterine and ovarian samples were performed. CAP-exposed females presented a reduced number of corpus luteum; glands and epithelial cells were increased with pinopodes formation impairment. Immunohistochemistry analysis revealed decreased LIF protein levels. These preliminary data suggests that PM exposure may exert negative effects on endometrial receptivity by affecting crucial parameters to embryonic implantation as uterine morphological differentiation, corpus luteum quantity and LIF expression during implantation window.

Neighborhood deprivation and racial differences in in vitro fertilization outcomes

BACKGROUND

There are significant racial disparities in in vitro fertilization outcomes, which are poorly explained by individual-level characteristics. Environmental factors such as neighborhood-level socioeconomic factors may contribute to these disparities. However, few studies have directly addressed this research question in a large, racially diverse cohort.

OBJECTIVE

This study aimed to investigate whether neighborhood deprivation is associated with differences in in vitro fertilization outcomes.

STUDY DESIGN

Our retrospective cohort study included 1110 patients who underwent 2254 autologous in vitro fertilization cycles between 2014 and 2019 at an academic fertility center in the Southeastern United States. Neighborhood deprivation was estimated using the Neighborhood Deprivation Index, a composite variable measuring community levels of material capital based on poverty, occupation, housing, and education domains. Using multivariable log-binomial generalized estimating equations with cluster weighting, risk ratios and 95% confidence intervals were estimated for cycle cancellation, miscarriage (defined as spontaneous pregnancy loss before 20 weeks after a confirmed intrauterine gestation), and live birth according to patient Neighborhood Deprivation Index.

RESULTS

There were positive associations between increasing Neighborhood Deprivation Index (indicating worsening neighborhood deprivation) and body mass index, as well as increasing prevalence of tubal and uterine factor infertility diagnoses. The crude probability of live birth per cycle was lower among Black (24%) than among White patients (32%), and the crude probability of miscarriage per clinical pregnancy was higher among Black (22%) than among White patients (12%). After adjustment, the Neighborhood Deprivation Index was not significantly associated with risk of cycle cancellation or live birth. Results were consistent when analyses were stratified by race.

CONCLUSION

Our research demonstrates racial disparities between Black and White women in the incidence of miscarriage and live birth following in vitro fertilization. Although the level of neighborhood deprivation was closely related to race, it did not have strong associations with in vitro fertilization outcomes in our population as a whole or within strata of race.

Racial disparity in uterine leiomyoma: new insights of genetic and environmental burden in myometrial cells

Uterine leiomyoma (LM), also known as uterine fibroids, are common gynecological tumors and can reach a prevalence of 70% among women by the age of 50 years. Notably, the LM burden is much higher in Black women with earlier onset, a greater tumor number, size, and severity compared to White women. Published knowledge shows that there are genetic, environmental, and lifestyle-based risk factors associated with racial disparity for LM. Significant strides have been made on genomic, epigenomic, and transcriptomic data levels in Black and White women to elucidate the underlying pathomolecular reasons of racial disparity in LM development. However, racial disparity of LM remains a major area of concern in gynecological research. This review highlights risk factors of LM and their role in different races. Furthermore, we discuss the genetics and uterine myometrial microenvironment in LM development. Comparative findings revealed that a major racial difference in the disease is linked to myometrial oxidative burden and altered ROS pathways which is relevant to the oxidized guanine in genomic DNA and MED12 mutations that drive the LM genesis. Considering the burden and morbidity of LM, we anticipate that this review on genetic risk and myometrial microenvironment will strengthen understanding and propel the growth of research to address the racial disparity of LM burden.

Uterine Fibroid Prevalence in a Predominantly Black, Chicago-Based Cohort

(1) Objectives: To investigate the effect of individual-level, neighborhood, and environmental variables on uterine fibroid (UF) prevalence in a Chicago-based cohort. (2) Methods: Data from the Chicago Multiethnic Prevention and Surveillance Study (COMPASS) were analyzed. Individual-level variables were obtained from questionnaires, neighborhood variables from the Chicago Health Atlas, and environmental variables from NASA satellite ambient air exposure levels. The Shapiro-Wilk test, logistic regression models, and Spearman's correlations were used to evaluate the association of variables to UF diagnosis. (3) Results: We analyzed 602 participants (mean age: 50.3 ± 12.3) who responded to a question about UF diagnosis. More Black than White participants had a UF diagnosis (OR, 1.32; 95% CI, 0.62-2.79). We observed non-significant trends between individual-level and neighborhood variables and UF diagnosis. Ambient air pollutants, PM2.5, and DSLPM were protective against UF diagnosis (OR 0.20, CI: 0.04-0.97: OR 0.33, CI: 0.13-0.87). (4) Conclusions: Associations observed within a sample in a specific geographic area may not be generalizable and must be interpreted cautiously.

Association between leisure sedentary behaviour and uterine fibroids in non-menopausal women: a population-based study

OBJECTIVE

Sedentary behaviour is associated with a variety of adverse health outcomes, including obesity, oestrogen metabolism and chronic inflammation, all of which are related to the pathogenesis of uterine fibroids (UFs). This study aimed to explore the relationship between leisure sedentary time (LST) and UFs.

DESIGN

Cross-sectional.

SETTING

We conducted a cross-sectional analysis of data from patients from the Yunnan region in the China Multi-Ethnic Cohort Study.

PARTICIPANTS

A total of 6623 non-menopausal women aged 30-55 years old were recruited. Menstrual status was self-reported. Participants who lacked a unique national identity card, suffered from serious mental illness, did not have a clear diagnosis of UFs, or provided incomplete information were excluded.

PRIMARY AND SECONDARY OUTCOME

UFs were diagnosed by abdominal B-ultrasound. Leisure sedentary behaviour was assessed by using a face-to-face questionnaire interview. Logistic regression and restricted cubic spline were employed to explore the relationship between LST and UFs.

RESULTS

A total of 562 participants had UFs, with a prevalence rate of 8.5% (7.8%, 9.2%). Multivariate adjusted logistic regression analysis showed that the risk of UFs in women with LST≥6 hour/day was 2.008 times that in women with LST<2 hour/day (95% CI 1.230 to 3.279). The restricted cubic spline results showed that there was a linear dose‒response relationship between LST and UFs (p for non-linearity>0.05). According to the results of the stratified analysis for menstrual status and body mass index (BMI), there was a correlation between LST and the prevalence of UFs only in women with a BMI<24 kg/m2 or perimenopause.

CONCLUSION

LST was independently associated with the prevalence of UFs, and a linear dose‒response relationship was observed. Our study provides evidence on the factors influencing UFs, and further research is needed to propose feasible measures for UFs prevention.

The impact of air pollution and endocrine disruptors on reproduction and assisted reproduction

PURPOSE OF REVIEW

Rapid increase in world population accompanied by global industrialization has led to an increase in deployment of natural resources, resulting in growing levels of pollution. Here, we review recent literature on the impact of environmental pollution on human reproductive health and assisted reproduction outcomes, focusing on two of the most common: air pollution and endocrine disruptors.

RECENT FINDINGS

Air pollution has been associated with diminished ovarian reserve, uterine leiomyoma, decreased sperm concentration and motility. Air pollution also correlates with decreased pregnancy rates in patients undergoing infertility treatment using in-vitro fertilization (IVF). Similarly, Bisphenol A (BPA), a well studied endocrine disrupting chemical, with oestrogen-like activity, is associated with diminished ovarian reserve, and abnormal semen parameters, while clinical implications for patients undergoing infertility treatment remain to be established.

SUMMARY

There is convincing evidence that environmental pollutants may have a negative impact on human health and reproductive potential. Air pollutions and endocrine disrupting chemicals found in water and food seem to affect male and female reproductive function. Large-scale studies are needed to determine the threshold values for health impact that may drive targeted policies.

Driving factors behind the continuous increase of long-term PM2.5-attributable health burden in India using the high-resolution global datasets from 2001 to 2020

Air pollution is the fourth leading global risk factor, whereas in India air pollution is reported as the highest risk factor with millions of premature deaths every year. Despite implementation of several air pollution control plans, PM_2.5 levels over India have not noticeably reduced. PM_2.5-associated health burdens in India have increased significantly in past decades. A fine resolution (0·01° × 0·01°) analysis of PM_2.5-attribulable premature deaths (rather than the coarse-level analysis) may elucidate the reason for this increase and inform and effective start-of-the-art state-level and national emission control strategies. This study quantified the spatiotemporal dynamics of PM_2.5-attributable premature deaths from 2001 to 2020 and applied a decomposition analysis to dissect the contribution of various associated parameters, such as PM_2.5 concentration, population distribution and disease-specific baseline death rate. Results show significant spatiotemporal variations of PM_2.5 and associated health burden in India. During the study period, population weighted PM_2.5 value increased from 46.0 to 59.5 μg/m³ and associated non-communicable death increased around 87.6 %, from 1050 [95 % (CI): 880-1210] thousand to 1970 (95 % CI: 1658-2259) thousand. The states of Uttar Pradesh, Bihar, West Bengal, Maharashtra, Rajasthan, and Madhya Pradesh had the highest PM_2.5-attributable deaths. In these states, non-accidental deaths increased from 232.1, 112.7, 81.4, 79.1, 66.3 and 58.5 thousand in 2001 to 424.1, 226.7, 156.2, 154.5, 123.3 and 119.7 thousand in 2020. In per capita population (/10⁵ population), the highest PM_2.5-attributable deaths were observed in Delhi, Uttar Pradesh, Bihar, Haryana and Punjab. Throughout the study period, demographic changes outweighed the health burden and were responsible for ~62.8 % increase of PM_2.5-related non-accidental deaths across India, whereas the change in PM_2.5 concentration influenced only 18.7 %. The change in baseline mortality rate impacts differently for the estimation of disease-specific mortality changes. Our findings suggest more dynamic and comprehensive policies at state-specific level, especially for North India is very indispensable for the overall decrease of PM_2.5-related deaths in India.

Gene Expression Profile of Uterine Leiomyoma from Women Exposed to Different Air Pollution Levels in Metropolitan Cities of Sao Paulo, Brazil

Leiomyomas (LMs) are the most frequent uterine benign tumors, representing the leading cause of hysterectomy indications worldwide. They are highly associated with women's reproductive complications, and endocrine disruptors may influence their etiology. In this sense, air pollution represents a relevant hormonal disruptor that acts on key signaling pathways, resulting in tumor development and infertility. Our goal was to evaluate submucosal LM samples from patients living in the metropolitan and Sao Paulo city regions, focusing on genes involved in tumor development and infertility features. Twenty-four patients were selected based on their region of residence and clinical information availability. Several genes were differentially expressed between women living in metropolitan areas and Sao Paulo city. Significant associations were observed between BCL-2, DVL1, FGFR3, and WNT5b downregulation and contraceptive use in the samples from women living in Sao Paulo city. ESR1 and HHAT downregulation was associated with ethnicity. WNT5b and GREM were associated with LM treatment and related pathologies, respectively. In the samples from women living in other cities of the metropolitan region, abortion occurrence was associated with BMP4 upregulation. Although further studies may be necessary, our results showed that air pollution exposure influences the expression of genes related to LM development and female reproductive features.

Bibliometric Analysis Reveals the Progress of PM2.5 in Health Research, Especially in Cancer Research

PM_2.5 has an aerodynamic diameter of less than or equal to 2.5 microns due to its inherent physical and chemical properties so that it can enter the alveoli through the respiratory tract for blood gas exchange. Numerous studies have shown that PM_2.5 is a serious air pollutant that poses a wide range of health risks, especially for cancer. Bibliometric methods were employed to have comprehensively analyzed the research of PM_2.5 in cancer for about a decade in Web of Science to identify hotspots and trends using VOSviewer, CiteSpace, and R. The field has undergone overall growth in the past decade. As research on PM_2.5 in health deepens, cancer related to it expanded beyond the respiratory system to the digestive system, urinary system, female gonadal axis, breast cancer and other cancers. Another observation is that research on PM_2.5 in cancer has progressed in the mechanisms of deterioration, such as the role of matrix metalloproteinases in cancer. In addition, research on the risks of PM_2.5 in combination with polycyclic aromatic hydrocarbons and heavy metals has also emerged. Results showed that there are relatively more studies on PM_2.5 in high-latitude countries, which may be due to different national conditions, such as climate and coal combustion. Our research has combed through the progress of PM_2.5 in cancer research and provided a supplement for developing pollution prevention ideas with different national conditions in this field.