Sulfur dioxide may predominate in the adverse effects of ambient air pollutants on semen quality among the general population in Hefei, China

Critical windows for exposure to chemical composition of ambient particulate matter and human semen quality decline

BACKGROUND

Critical windows for exposure to chemical components of particulate matter (PM <2.5 μm in diameter [PM2.5]) associated with the human semen quality decline remain unclear.

OBJECTIVES

To address this gap, we developed a new analytical framework by integrating a Linear Mixed Model (LMM) with subject- and center-specific intercepts and a Distributed Lag Model (DLM) to fully account for correlations between finely vulnerable exposure windows based on complete profile of the spermatogenesis cycle.

METHODS

We constructed a multicenter cohort involving 33,234 sperm donors with 78,952 semen samples covering 6 representative regions across China from 2014 to 2020 to investigate the week-scale critical windows for the exposure. Daily exposure to PM2.5 chemical components of donors was derived from grid data based on 1-km spatial resolution surface measurements.

RESULTS

Decreased sperm count was significantly associated with NO3- and SO42- at 9-10 weeks (e.g., β: -0.05 %, 95%CI: [-0.10 %, -0.00 %] at the 9th week) and 0-2 weeks (e.g., β: -0.66 %, 95%CI: [-1.24 %, -0.07 %] at the 1st week), respectively. Critical windows of progressive motility decline were 0-10 weeks for BC (e.g., β: -0.07 %, 95%CI: [-0.11 %, -0.03 %] at the 5th week), Cl- at 1-4 weeks (e.g., β: -2.21 %, 95%CI: [-3.77 %, -0.66 %] at the 2nd week), 0-6 weeks and 9-10 weeks for NO3- (e.g., β: -0.05 %, 95%CI: [-0.09 %, -0.01 %] at the 4th week), 1-3 weeks and the 8th week for NH4+ (e.g., β: -0.06 %, 95%CI: [-0.11 %, -0.01 %] at the 2nd week). Total motility is significantly negatively associated with BC at entire windows, Cl- at 0-3 weeks, the 5th week and 9-10 weeks.

CONCLUSIONS

There are week-scale vulnerable windows of exposure to PM2.5 chemical components for human semen quality. This highlights the need for more targeted pollution control strategies addressing PM2.5 and its chemical components.

Effect of nitrogen oxides and sulfur oxides to triphenyl phosphate degradation and cytotoxicity on surface of different transition metal salts

Nitrogen oxides and sulfur oxides, as the dominant toxic gases in the atmosphere, can induce severe human health problems under the composite pollutant conditions. Currently the effect of nitrogen or sulfur oxides in atmospheric environment to the degradation and cytotoxicity of triphenyl phosphate (TPhP) on atmospheric particle surfaces still remain poorly understood. Hence, laboratory simulation methods were used in this study to investigate the effect and related mechanism. First, particle samples were prepared with the TPhP coated on MnSO4, CuSO4, FeSO4 and Fe2(SO4)3 surface. The results showed that, when nitrogen or sulfur oxides were present, more significant TPhP degradation on all samples can be observed under both light and dark conditions. The results proved nitrogen oxides and sulfur oxides were the vital influence factors to the degradation of TPhP, which mainly promoted the OH generation in the polluted atmosphere. The mechanism study indicated that diphenyl hydrogen phosphate (DPhP) and OH-DPhP were two main stable degradation products. These degradation products originated from the phenoxy bond cleavage and hydroxylation of TPhP caused by hydroxyl radicals. In addition, no TPhP related organosulfates (OSs) or organic nitrates (ON) formation were observed. Regarding the cytotoxicity, all the particles can induce more significant cellular injury and apoptosis of A549 cells, which may be relevant to the adsorbed nitrogen oxides or sulfur oxides on particles surfaces. The superfluous reactive oxygen species (ROS) generation was the possible reason of cytotoxicity. This research can supply a comprehensive understanding of the promoting effect of nitrogen and sulfur oxides to TPhP degradation and the composite cytotoxicity of atmospheric particles.

The relationship between air pollution and the occurrence of hypertensive disorders of pregnancy: Evidence from a study in Wuhan, China

Ambient air pollution has been reported to be a risk factor for hypertensive disorders of pregnancy (HDP). Past studies have reported supportive evidence, but evidence from China is scarce and does not integrate the different periods of the pregnancy course. In this study, 1945 pregnant women with HDP and healthy pregnancies between 2016 and 2022 from the Renmin Hospital of Wuhan University registry network database were analysed. The geographic information, biological information and demographic information of the case were fused in the analysis. Machine learning methods were used to obtain the weight of the variable. Then, we used the generalized linear mixed model to evaluate the relationship between increased exposure to each pollutant at different periods of HDP and examined it in different groups. The results showed that SO2 had the predominate impact (12.65 %) on HDP compared with other air pollutants. SO2 exposure was associated with an increased risk of HDP. Increased unit SO2 concentrations were accompanied by an increased risk of HDP (OR = 1.33, 95 % CI: 1.13, 1.566), and the susceptible window for this effect was mainly in the first trimester (OR = 1.242, 95 % CI: 1.092, 1.412). In addition, SO2 exposure was associated with an increased risk of HDP in urban maternity (OR = 1.356, 95 % CI: 1.112, 1.653), obese maternity (OR = 3.58, 95 % CI: 1.608, 7.971), no higher education maternity (OR = 1.348, 95 % CI: 1.065, 1.706), nonzero delivery maternity (OR = 1.981, 95 % CI: 1.439, 2.725), maternal with first time maternity (OR = 1.247, 95 % CI: 1.007, 1.544) and other groups. In summary, SO2 exposure in early pregnancy is one of the risk factors for HDP, and the increased risk of HDP due to increased SO2 exposure may be more pronounced in obese, urban, low-education, and nonzero delivery populations.

Negative association of atmospheric pollutants with semen quality: A cross-sectional study in Taiyuan, China

BACKGROUND

In recent decades, the quality of male semen has decreased worldwide. Air pollution has been linked to lower semen quality in several studies. However, the effects of atmospheric pollutants on different semen characteristics have not always been consistent. The aim of this study was to investigate the association between the Air Quality Index (AQI) and six atmospheric pollutants (PM2.5, PM10, SO2, NO2, CO, and O3), semen quality, and their key exposure window periods.

METHODS

This study included 1711 semen samples collected at the reproductive clinics of the First Affiliated Hospital of Shanxi Medical University in Taiyuan, Shanxi, China, from October 10, 2021, to September 30, 2022. We evaluated the association of AQI and six atmospheric pollutants with semen quality parameters throughout sperm development and three key exposure windows in men using single-pollutant models, double-pollutant models, and subgroup analyses of semen quality-eligible groups.

RESULTS

Both the single-pollutant model and subgroup analyses showed that PM, CO, and O3 levels were negatively correlated with total and progressive motility. At 70-90 d before semen collection, CO exposure and semen volume (β =-1.341, 95 % CI: -1.805, -0.877, P <0.001), total motility (β =-2.593, 95 % CI: -3.425, -1.761, P <0.001), and progressive motility (β =-4.658, 95 % CI: -5.556, -3.760, P <0.001) were negatively correlated. At 0-9 days before semen collection, CO was negatively correlated with normal morphology (β =-3.403, 95 % CI: -5.099, -1.708, P <0.001). Additionally, the AQI was adversely associated with total and progressive motility in subgroup analyses of the semen quality-eligible groups.

CONCLUSIONS

During the entire sperm development process, multiple air pollutants were determined to have an adverse correlation with semen quality parameters. AQI was significant marker for the combined effects of various atmospheric pollutants on male reproductive health.

Individual and joint associations of air pollutants exposure with semen quality: A retrospective longitudinal study in Wenzhou, China

PURPOSE

The impact of air pollution on semen quality has been confirmed, yet the joint effect remains unclear. We evaluate the individual and joint associations of particulate (PM2.5 and PM10) and gaseous pollutants (NO2, SO2, O3 and CO) with semen quality.

METHODS

We included 5,114 men in this study from 2014 to 2022. The individual and joint associations were measured by multiple linear regression models.

RESULTS

Sperm motility and semen volume were inversely associated with pollutant concentrations during every stage of sperm development, especially at lag days 0-9 and 10-14 (all P < 0.05). Stratified analyses showed that the study pollutants (except CO) had a positive effect on semen concentration during the stage of sperm development, especially in spring and autumn, while a decreased total sperm number was associated with CO (all P < 0.05). However, joint associations of particulate and gaseous pollutants with semen quality parameters were not statistically significant (all P > 0.05).

CONCLUSIONS

During all stages of sperm development, particulate and gaseous pollutants had individual negative impacts on sperm motility and semen volume, and these impacts were less pronounced in spring and autumn. Our findings highlight the importance and necessity of reducing the exposure to pollutants especially in the critical stage of sperm development to improve semen quality.

Exposure to ambient ozone and sperm quality among adult men in China

BACKGROUND

Limited evidence exists regarding the association between ozone exposure and adverse sperm quality. We aimed to assess the association between ozone exposure and sperm quality, and identify susceptible exposure windows.

METHODS

We recruited 32,541 men aged between 22 and 65 years old attending an infertility clinic in Wuhan, Hubei Province, China from 2014 to 2020. Ozone data were obtained from a satellite-based spatiotemporal model. Generalized linear models were used to estimate the association between ozone exposure and sperm quality parameters, including sperm concentration, sperm count, sperm total motility, and sperm progressive motility during the entire stage of sperm development (0-90 days before ejaculation) and three crucial stages (0-9 days, 10-14 days and 70-90 days before ejaculation). Stratified analyses were performed to evaluate whether associations varied by age, body mass index, and education levels.

RESULTS

The final analysis included 27,854 adult men. A 10 μg/m3 increase in ozone concentrations during the entire stage of sperm development was associated with a -4.17 % (95 % CI: -4.78 %, -3.57 %) decrease in sperm concentration, -6.54 % (95 % CI: -8.03 %, -5.60 %) decrease in sperm count, -0.50 % (95 % CI: -0.66 %, -0.34 %) decrease in sperm total motility, and -0.07 % (95 % CI: -0.22 %, 0.09 %) decrease in sperm progressive motility. The associations were stronger during 70-90 days before ejaculation and among men with middle school and lower education for sperm concentration.

CONCLUSIONS

Ozone exposure was associated with decreased sperm quality among Chinese adult men attending an infertility clinic. These results suggest that ozone may be a risk factor contributing to decreased sperm quality in Chinese men.

Association between air pollution and male sexual function: A nationwide observational study in China

This study aimed to explore the associations between air pollution and male sexual function. A total of 5047 male subjects in China were included in this study. The average air pollution exposure (PM2.5, PM10, SO2, CO, NO2, and O3) for the preceding 1, 3, 6, and 12 months before the participants' response was assessed. Male sexual function was evaluated using the International Index of Erectile Function-5 (IIEF-5) and the Premature Ejaculation Diagnostic Tool (PEDT). Generalized linear models were utilized to explore the associations between air pollution and male sexual function. K-prototype algorithm was conducted to identify the association among specific populations. Significant adverse effects on the IIEF-5 score were observed with NO2 exposure during the preceding 1, 3, and 6 months (1 m: β = -5.26E-05; 3 m: β = -4.83E-05; 6 m: β = -4.23E-05, P < 0.05). PM2.5 exposure during the preceding 12 months was found to significantly negatively affect the PEDT after adjusting for confounding variables. Our research indicated negative correlations between air pollutant exposures and male sexual function for the first time. Furthermore, these associations were more pronounced among specific participants who maintain a normal BMI, exhibit extroverted traits, and currently engage in smoking and alcohol consumption.

Implications of Exposure to Air Pollution on Male Reproduction: The Role of Oxidative Stress

Air pollution, either from indoor (household) or outdoor (ambient) sources, occurs when there is presence of respirable particles in the form of chemical, physical, or biological agents that modify the natural features of the atmosphere or environment. Today, almost 2.4 billion people are exposed to hazardous levels of indoor pollution, while 99% of the global population breathes air pollutants that exceed the World Health Organization guideline limits. It is not surprising that air pollution is the world's leading environmental cause of diseases and contributes greatly to the global burden of diseases. Upon entry, air pollutants can cause an increase in reactive oxygen species (ROS) production by undergoing oxidation to generate quinones, which further act as oxidizing agents to yield more ROS. Excessive production of ROS can cause oxidative stress, induce lipid peroxidation, enhance the binding of polycyclic aromatic hydrocarbons (PAHs) to their receptors, or bind to PAH to cause DNA strand breaks. The continuous and prolonged exposure to air pollutants is associated with the development or exacerbation of pathologies such as acute or chronic respiratory and cardiovascular diseases, neurodegenerative and skin diseases, and even reduced fertility potential. Males and females contribute to infertility equally, and exposure to air pollutants can negatively affect reproduction. In this review, emphasis will be placed on the implications of exposure to air pollutants on male fertility potential, bringing to light its effects on semen parameters (basic and advanced) and male sexual health. This study will also touch on the clinical implications of air pollution on male reproduction while highlighting the role of oxidative stress.

Sperm quality decline associated with gaseous pollutant exposure: Evidence from a large cohort multicenter study

BACKGROUND

Poor sperm quality is a prevalent cause of male infertility, and the association between gaseous ambient air pollutants exposure and semen quality remains unclear.

OBJECTIVES

To examine the relationship between gaseous air pollution exposure with semen quality in a large-scale and multi-center study.

METHODS

We analyzed 78,952 samples corresponding to 33,234 study subjects from 2014 to 2020. The high-resolution grid pollution dataset was used to estimate personal exposures to CO, SO2, NO2 and O3 across entire stage of semen formation and three crucial stages. The linear mixed models were performed to evaluate the relationships.

RESULTS

The results showed that sperm count was inversely related to SO2 exposure (-0.0070, -0.0128 to -0.0011). Decreased sperm concentration was associated with SO2 (-0.0083, -0.0142 to -0.0024), NO2 (-0.0162, -0.0320 to -0.0005) and O3 (-0.0306, -0.0480 to -0.0133) during 0-90 lag days, respectively. Additionally, we observed significant decline of PR and total motility with SO2 exposure. Similar trends were observed for SO2 and CO exposure during 3 key periods.

CONCLUSIONS

Our findings suggest that exposure to gaseous air pollutants may have negative impacts on sperm quality. These findings highlight the importance that critical periods of sperm development should be considered when implementing protective measures.

Effect of short-term ambient air pollution exposure on early miscarriage and pregnancy hormones with critical window identification

BACKGROUND

Pregnancy hormones are particularly important in early miscarriage, and some evidence suggests that exposure to air pollution is associated with pregnancy hormones and miscarriage. However, the effects of air pollution on pregnancy hormone-mediated miscarriages have not yet been investigated.

METHODS

We collected air pollution exposure measurements and pregnancy hormone tests from the participants. Logistic regression models were used to investigate the association between air pollution and early miscarriages. A distributed lag nonlinear model (DLNM) was used to investigate non-linear and delayed associations and identify the crucial window. We performed mediation analysis to estimate the potential association that may exist between pregnancy hormone levels and early miscarriage.

RESULTS

Short-term exposure to CO and SO2 was associated with early miscarriage. Lag 22-28 days of exposure to both CO and SO2 and lag 15-21 days of exposure to CO were significantly positively associated with early miscarriage, with an obvious exposure dose response. Serum progesterone concentration explained 36.79 % of the association between lag 15-28 days of CO exposure and early miscarriage.

CONCLUSION

This study provides evidence for the association between short-term exposure to air pollution and early miscarriage, and provides clues for further exploration of biological mechanisms.

An update on the association between ambient short-term air pollution exposure and daily outpatient visits for conjunctivitis: a time-series study in Hangzhou, China

Air pollution is a major public health problem that can lead to conjunctivitis. This study aimed to explore the associations between air pollutants and outpatient visits for conjunctivitis in Hangzhou, China. This study collected data on 50,772 patients with conjunctivitis and the concentrations of six air pollutants from February 1, 2014, to August 31, 2018. A time series analysis using a generalized additive model (GAM) was conducted. We found that the risk of conjunctivitis was related to the air pollutants PM2.5, PM10, SO2, NO2, and O3, which had concentration hysteresis effects. The risk of conjunctivitis increased by 1.009 (95% confidence interval (CI): 1.003, 1.014), 1.011 (95% CI: 1.008, 1.015), 1.238 (95% CI: 1.186, 1.292), 1.028 (95% CI: 1.019, 1.038), and 1.013 (95% CI: 1.008, 1.017) for every 10 µg/m3 increase in PM2.5, PM10, SO2, NO2, and O3 concentrations, respectively. The lag effects of SO2 and NO2 were stronger than those of particulate matter. Females exposed to PM10, PM2.5, SO2, and O3 had a higher risk of conjunctivitis than males, while males exposed to NO2 had a nearly identical risk of conjunctivitis as females. People aged 19-59 were more likely to suffer from conjunctivitis. The risk of conjunctivitis caused by PM10, SO2, and O3 was highest in the transitional season, while the risk caused by NO2 was highest in the winter season. In conclusion, females and middle-aged adults were at higher risk of conjunctivitis. People were more susceptible to conjunctivitis during the transitional season. These findings highlight the importance of atmospheric pollution governance and reference for public health measures.

Higher serum AMH level is associated with better pregnancy outcomes of IVF/ICSI assisted pregnancy in infertile patients under 35 years old

This study aimed to investigate the effect of anti-Mullerian hormone (AMH) on the pregnancy outcome of infertility assisted by IVF/Micro-Insemination/Embryo Transfer Infertility Assistance (IVF/ICSI-ET). A total of 324 patients under the age of 35 who received IVF/ICSI-ET assistance in our center were included in this analysis. AMH levels of these patients were measured by chemiluminescence method and divided into clinical pregnancy group (175 cases) and non-pregnancy group (149 cases) according to the final pregnancy outcome. The relationship between the two groups' pregnancy outcomes and AMH levels was analyzed. The above association was re-evaluated after excluding patients with polycystic ovary syndrome. There was no significant difference in age, body mass index (BMI), follicle-stimulating hormone (FSH), and 2 pronucleus (PN) between clinical and non-clinical pregnancy groups. Compared with the clinical pregnancy group, the level of AMH in the non-pregnancy group was significantly lower (p < 0.05). A higher AMH level was closely related to better IVF/ICSI-ET assisted pregnancy outcome in vitro. After excluding AMH abnormalities, the AMH level was still significantly associated with pregnancy outcomes of in vitro IVF/ICSI-ET-assisted pregnancy. Our results show a correlation between AMH level and pregnancy outcome of in vitro IVF/ICSI-ET assisted pregnancy. For women under age 35, lower AMH levels may be one of the predictors of adverse pregnancy outcomes. For patients with low AMH level, it is suggested to strengthen monitoring to ensure the safety and smoothness of the pregnancy process.