The role of air pollutants in initiating liver disease

Fine particulate matter exposure and cancer risk: a systematic review and meta-analysis of prospective cohort studies

Studies examining the relationship between fine particulate matter (PM2.5) exposure and cancer risk is inconclusive, with an evident scarcity of comprehensive data on the overall cancer risk. Given the emergence of new evidence, updated meta-analyses is essential. A search was performed on multiple databases including PubMed, Embase, Scopus, Web of Science, and the Cochrane Library up to Jan 2025. Hazard ratios (HRs), relative risks (RRs), or incidence rate ratios (IRRs) with their 95 % confidence intervals (CIs) were extracted and pooled. Moreover, a comprehensive and detailed quality assessment of the included studies was conducted to validate the plausibility of the findings. Overall, 57 original studies were included, covering 36 cancer categories and including overall cancer and malignancies specific to particular anatomical sites. For each increase of 10 μg per cubic meter in PM2.5 concentration, there was an observed pooled HR of 1.07 for overall cancer (95 %CI:1.02-1.13). In the case of site-specific cancers, the pooled HRs were 1.11 (95 %CI:1.07-1.15), 1.06 (95 %CI:1.02-1.11), 1.17 (95 %CI:1.07-1.28), and 1.14 (95 %CI:1.03-1.26) for lung, breast, liver and esophageal cancers, respectively. Furthermore, PM2.5 exposure may potentially correlate with the risk of cancers at other anatomical locations including upper aerodigestive tract, oral cavity, kidney, skin, as well as digestive organs. In light of available evidence, it is inferred that PM2.5 exposure could potentially raise overall cancer risk with moderate certainty. As for site-specific malignancies, there is very low certainty evidence for lung cancer, low certainty evidence for breast cancer, and moderate certainty evidence for both liver and esophageal cancers.

Exposure to airborne particulate matter and undernutrition in young rats: An in-depth histopathological and biochemical study on lung and excretory organs

Environmental stressors, such as air particulate matter (PM) and nutrient deficiencies, can significantly impact crucial organs involved in detoxifying xenobiotics, including lungs, liver, and kidneys, especially in vulnerable populations like children. This study investigated the effect of 4-week exposure to Residual Oil Fly Ash (ROFA) on these organs in young rats under growth-restricted nutrition (NGR). We assessed histological, histomorphometric and biochemical parameters. ROFA exposure induced histological changes and inflammation in all three organs when compared to control (C) animals. Specifically, in lungs ROFA caused a significant reduction in alveolar airspace (C: 55.8 ± 1.8% vs. ROFA: 38.7 ± 3.0%, p < 0.01) and alveolar number along with changes in alveolar size distribution, and disruption of the smooth muscle layer which may impaired respiratory function. In the liver, ROFA increased binucleated cells, macro and microvesicles and both AST and ALT serum biomarkers (AST: C = 77.7 ± 1.3 vs. ROFA = 81.6 ± 1.3, p < 0.05; ALT: C = 44.5 ± 0.9 vs. ROFA = 49.4 ± 1.3, p < 0.05). In the kidneys, a reduced Bowman's space (C: 2.15 ± 0.2 mm2 vs. ROFA: 1.74 ± 0.2 mm2, p < 0.05) was observed, indicative of glomerular filtration failure. NGR alone reduced Bowman's space (C: 2.15 ± 0.2 mm2 vs. NGR: 1.06 ± 0.1 mm2, p < 0.001). In lung and liver NGR showed higher levels of proinflammatory cytokine IL-6 (p < 0.01 and p < 0.001, respectively) when compared to C. In conclusion, both stressors negatively affected lung and excretory organs in young rats, with nutritional status further modulating the physiological response to ROFA. These findings highlight the compounded risks posed by environmental pollutants and poor nutrition in vulnerable populations.

Effects of air pollution on the development and progression of digestive diseases: an umbrella review of systematic reviews and meta-analyses

Air pollution, especially particulate matter (PM), is one of the most common risk factors for global burden of disease. However, its effect on the risk of digestive diseases is unclear. Herein, we attempt to explore this issue by reviewing the existing evidence from published meta-analyses. We conducted a systematic literature search to identify all relevant meta-analyses regarding the association of air pollution with digestive diseases, and summarize their major findings. We assessed the methodological quality and evidence quality of the included meta-analyses using the AMSTAR-2 and GRADE tools, respectively, and the overlap of primary studies was assessed by the GROOVE tool. Nine meta-analyses were included in our analysis, containing 43 primary studies with high overlap. In the included meta-analyses, the methodological quality was from critically low to moderate, and the evidence quality was from very low to moderate. The exposure was primarily PM2.5. Seven, four, and one meta-analysis investigated the effect of air pollution on liver diseases, gastrointestinal diseases, and pancreatic diseases, respectively. PM2.5 exposure was significantly associated with liver dysfunction, chronic liver diseases, liver cancer, and colorectal cancer, but not oesophagus cancer, gastric cancer, or pancreatic cancer. Based on very low to moderate quality evidence from meta-analyses, PM2.5 exposure may contribute to the development of some digestive diseases, especially liver diseases.

Constructing an adverse outcome pathway framework for the impact of maternal exposure to PM2.5 on liver development and injury in offspring

Ambient fine particulate matter (PM2.5) is a significant contributor to air pollution. PM2.5 exposure poses a substantial hazard to public health. In recent years, the adverse effects of maternal PM2.5 exposure on fetal health have gradually gained public attention. As the largest organ in the body, the liver has many metabolic and secretory functions. Liver development, as well as factors that interfere with its growth and function, are of concern. This review utilized the adverse outcome pathway (AOP) framework as the analytical approach to demonstrate the link between maternal PM2.5 exposure and potential neonatal liver injury from the molecular to the population level. The excessive generation of reactive oxygen species (ROS), subsequent endoplasmic reticulum (ER) stress, and oxidative stress were regarded as the essential components in this framework, as they could trigger adverse developmental outcomes in the offspring through DNA damage, autophagy dysfunction, mitochondrial injury, and other pathways. To the best of our knowledge, this is the first article based on an AOP framework that elaborates on the influence of maternal exposure to PM2.5 on liver injury occurrence and adverse effects on liver development in offspring. Therefore, this review offered mechanistic insights into the developmental toxicity of PM2.5 in the liver, which provided a valuable basis for future studies and prevention strategies.

Associations of ambient particulate matter and household fuel use with chronic liver disease in China: A nationwide analysis

BACKGROUND

Long-term effects of outdoor and indoor air pollution on chronic liver disease (CLD) remain unclear. Thus, the study was conducted to investigate the relationship between prolonged exposure to ambient particulate matter (PM1, PM2.5 and PM10) and household fuel usage with CLD.

METHODS

Data from the China Health and Retirement Longitudinal Study (CHARLS) covering the years 2011 to 2020 were employed. In the cross-sectional analysis, 16,680 participants were included, while 12,969 participants were enrolled in the longitudinal study. The associations between various sizes of particulate matter and CLD were elucidated using logistic regression model and generalized linear-mixed models. Additionally, the additive effects of ambient particulate matter (PM) levels and the utilization of solid fuels for cooking were investigated, with a comparison of effect sizes between converted and non-converted fuel types.

RESULTS

Over a 10-year follow-up period, 746 (5.75 %) individuals developed CLD. For a 1-year average concentrations, PM1, PM2.5 and PM10 were each linked to a 1.549 (95 %CI:1.522-1.576), 1.296 (95 %CI:1.276-1.317) and 1.134 (95 %CI:1.118-1.150) fold risk of incident CLD per 10 μg/m3 increase, respectively. A similar effect of PM concentrations over a 2-year period on CLD was observed. Moreover, simultaneous exposure to ambient PM and solid fuels is associated with an increased risk of CLD. Those who continue using solid fuels may face a higher risk of CLD compared to individuals who switch to cleaner cooking fuels. Female participants, smokers, and individuals with shorter sleep duration and multiple chronic diseases exhibited slightly stronger effects.

CONCLUSION

Long-term exposure to various sizes of PM (PM1, PM2.5, PM10) has been linked to an elevated risk of CLD incidence. Co-exposure to ambient PM and solid fuels is associated with higher health risks.

Daily estimation of NO2 concentrations using digital tachograph data

Traffic information is crucial for estimating NO2 concentrations, but it is static and limited in predicting constantly changing NO2 levels. To overcome these challenges, this study utilized real-time spatial big data to capture both the spatial and temporal fluctuations in traffic. Digital tachograph (DTG) data, sourced from digital devices in all commercial vehicles, are employed to construct a DTG land use regression (LUR) model, and its performance is compared with that of a non-DTG-LUR model. The DTG-LUR model exhibits superior performance, with an explanatory power of 0.46, in contrast to the 0.36 of the non-DTG model. This significant improvement stems from the spatially and temporally dynamic DTG variables such as cargo traffic. This study introduces a novel approach for incorporating DTG data in correlating with NO2 concentrations. It underscores the advantage of DTG data in predicting daily NO2 fluctuations at a precise 200-m grid, which is not feasible with conventional data. The findings of the study highlight the immense potential of spatial big data for fine-grained analyses, which could enable hourly predictions of air pollution.

Air pollutants and primary liver cancer mortality: a cohort study in crop-burning activities and forest fires area

Introduction

Northern Thailand experiences high levels of air pollution in the dry season due to agricultural waste burning and forest fires. Some air pollutants can enter the bloodstream, and the liver has the role of detoxifying these along with other harmful substances. In this study, we assessed the effects of long-term exposure to air pollutants on liver cancer mortality in this area.

Methods

A cohort of 10,859 primary liver cancer patients diagnosed between 2003 and 2018 and followed up to the end of 2020 were included in the study. Extended time-varying covariates of the annually averaged pollutant concentrations updated each year were utilized. The associations between air pollutants and mortality risk were examined by using a Cox proportional hazard model.

Results

Metastatic cancer stage had the highest adjusted hazard ratio (aHR) of 3.57 (95% confidence interval (CI):3.23-3.95). Being male (aHR = 1.10; 95% CI: 1.04-1.15), over 60 years old (aHR = 1.16; 95% CI: 1.11-1.21), having a history of smoking (aHR = 1.16; 95%CI: 1.11-1.22), and being exposed to a time-updated local concentration of PM2.5 of 40 μg/m3 (aHR = 1.10; 95% CI: 1.05-1.15) increased the mortality risk.

Conclusion

We found that air pollution is one of several detrimental factors on the mortality risk of liver cancer.

Air pollution induces morpho-functional, biochemical and biomechanical vascular dysfunction in undernourished rats

Air pollution (gases and particulate matter -PM) and child undernutrition are globally recognized stressors with significant consequences. PM and its components breach the respiratory alveolar-capillary barrier, entering the vasculature transporting not only harmful particles and its mediators but, altering vascular paracrine and autocrine functions. The aim of this study was to investigate the effects of Residual Oil Fly Ash (ROFA), on the vasculature of young animals with nutritional growth retardation (NGR). Weanling rats were fed a diet restricted 20% (NGR) compared to ad libitum intake (control-C) for 4 weeks. Rats were intranasally instilled with 1 mg/kg BW of ROFA. After 24h exposure, histological and immunohistochemical, biochemical and contractile response to NA/ACh were evaluated in aortas. ROFA induced changes in the tunica media of the aorta in all groups regarding thickness, muscular cells and expression of Connexin-43. ROFA increased TGF-β1 and decreased eNOs levels and calcium channels in C and NGR animals. An increment in cytokines IL-6 and IL-10 was observed in C, with no changes in NGR. ROFA exposure altered the vascular contractile capacity. In conclusion, ROFA exposure could increase the risk for CVD through the alteration of vascular biochemical parameters, a possible step of the endothelial dysfunction.

Long-term exposure to ambient fine particulate matter and risk of liver cancer in the NIH-AARP Diet and Health Study

BACKGROUND

Fine particulate matter (PM2.5) exposure has been associated with liver cancer incidence and mortality in a limited number of studies. We sought to evaluate this relationship for the first time in a U.S. cohort with historical exposure assessment.

METHODS

We used spatiotemporal prediction models to estimate annual average historical PM2.5 concentrations (1980-2015) at residential addresses of 499,729 participants in the NIH-AARP Diet and Health Study, a cohort in 6 states (California, Florida, Louisiana, New Jersey, North Carolina, and Pennsylvania) and 2 metropolitan areas (Atlanta, Georgia, and Detroit, Michigan) enrolled in 1995-1996 and followed up through 2017. We used a time-varying Cox model to estimate the association for liver cancer and the predominant histologic type, hepatocellular carcinoma (HCC), per 5 µg/m3 increase in estimated outdoor PM2.5 levels, incorporating a 5-year average, lagged 10 years prior to cancer diagnosis and adjusting for age, sex, race/ethnicity, education level and catchment state. We also evaluated PM2.5 interactions with hypothesized effect modifiers.

RESULTS

We observed a non-significantly increased risk of liver cancer associated with estimated PM2.5 exposure (Hazard ratio [HR] = 1.05 [0.96-1.14], N = 1,625); associations were slightly stronger for HCC, (84 % of cases; HR = 1.08 [0.98-1.18]). Participants aged 70 or older at enrollment had an increased risk of liver cancer versus other age groups (HR = 1.50 [1.01-2.23]); p-interaction = 0.01) and risk was elevated among participants who did not exercise (HR = 1.81 [1.22-2.70]; p-interaction = 0.01). We found no evidence of effect modification by sex, smoking status, body mass index, diabetes status, or alcohol consumption (p-interaction > 0.05).

CONCLUSIONS

Our findings in this large cohort suggest that residential ambient PM2.5 levels may be associated with liver cancer risk. Further exploration of the variation in associations by age and physical activity are important areas for future research.

Environmental surveillance in Jinan city of East China (2014-2022) reveals improved air quality but remained health risks attributable to PM2.5-bound metal contaminants

PM2.5-bound metal contaminants are associated with multiple chronic diseases in human. At global level, the contamination status has not been well controlled yet. Here we report findings from a long-term air pollution surveillance in Jinan city of Shandong, China. During 2014-2022, the dynamics and trends of PM2.5-bound heavy metal contaminants were monitored in an industrial area and a downtown area. The surveillance targets included: antimony (Sb), aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), mercury (Hg), lead (Pb), manganese (Mn), nickel (Ni), selenium (Se). The human exposure and health risks were calculated and we found that the health risks of most contaminants showed peak values in autumn and winter. But Al, Mn, Hg and Be were found to result in highest health risk in spring or summer in the downtown area. In the industrial area we identified 100% alarming health index >1 (ranged from 1.12 to 3.35) in autumn and winter. In winter the total non-carcinogenic HI was all above 1 (peak value 2.21). Mn and As together posed >85% non-carcinogenic risk. As and Cd were ranked as major drivers of carcinogenic risks (5.84 × 10-6 and 2.78 × 10-6). Pd and Cd both showed non-negligible environmental levels but risk assessment model for their air-exposure associated non-carcinogenic risks are not yet available. This study updates air pollution data and status for air pollution status in China. This study provides valuable 9 year long-term reference to experimental and field studies in the related fields.

A Chinese longitudinal maternity cohort study (2013-2021) on intrahepatic cholestasis phenotypes: Risk associations from environmental exposure to adverse pregnancy outcomes

Intrahepatic cholestasis of pregnancy (ICP) is an idiopathic disease that occurs during mid-to-late pregnancy and is associated with various adverse pregnancy outcomes, including intrauterine fetal demise. However, since the underlying cause of ICP remains unclear, there is an ongoing debate on the phenotyping criteria used in the diagnostic process. Here, we identified single- and multi-symptomatic ICP (ICP-S and ICP-M) in 104,221 Chinese females from the ZEBRA maternity cohort, with the objective of exploring the risk implications of the two phenotypes on pregnancy outcomes and from environmental exposures. We employed multivariate binary logistic regression to estimate confounder-adjusted odds ratios and found that ICP-M was more strongly associated with preterm birth and low birth weight compared to ICP-S. Throughout pregnancy, incremental exposure to PM2.5, O3, and greenness could alter ICP risks by 17.3%, 12.5%, and -2.3%, respectively, with more substantial associations observed with ICP-M than with ICP-S. The major scientific advancements lie in the elucidation of synergistic risk interactions between pollutants and the protective antagonistic effects of greenness, as well as highlighting the risk impact of preconceptional environmental exposures. Our study, conducted in the context of the "three-child policy" in China, provides epidemiological evidence for policy-making to safeguard maternal and neonatal health.

Pathophysiologic effects of waterpipe (shisha) smoke inhalation on liver morphology and function in mice

AIMS

The global prevalence of waterpipe tobacco smoking is increasing. Although the cardiorespiratory, renal, and reproductive effects of waterpipe smoking (WPS) are well-documented, there is limited knowledge regarding its adverse impact on the liver. Therefore, our study aimed to assess the effects and potential mechanisms of WPS inhalation for one or four weeks on the liver.

MAIN METHODS

Mice were exposed to WPS for 30 min per day, five days per week, while control mice were exposed to clean air.

KEY FINDINGS

Analysis using light microscopy revealed the infiltration of immune cells (neutrophils and lymphocytes) accompanied by vacuolar hepatic degeneration upon WPS inhalation. At the four-week timepoint, electron microscopy analysis demonstrated an increased number of mitochondria with a concomitant pinching-off of hepatocyte plasma membranes. WPS exposure led to a significant rise in the activities of liver enzymes alanine aminotransferase and aspartate aminotransferase in the bloodstream. Additionally, WPS inhalation elevated lipid peroxidation and reactive oxygen species levels and disrupted the levels of the antioxidant glutathione in liver tissue homogenates. The concentration of proinflammatory cytokines, including tumor necrosis factor α, interleukin (IL)-6, and IL-1β, was significantly increased in the WPS-exposed group. Furthermore, WPS inhalation induced DNA damage and a significant increase in the levels of cleaved caspase-3, cytochrome C and hypoxia-inducible factor 1α along with alterations in the activity of mitochondrial complexes I, II, III and IV.

SIGNIFICANCE

Our findings provide evidence that WPS inhalation triggers changes in liver morphology, oxidative stress, inflammation, DNA damage, apoptosis, and alterations in mitochondrial activity.

Does ambient air pollution influence biochemical markers of liver injury? Findings of a cross-sectional population-based survey

BACKGROUND

There is limited evidence supporting an adverse effect of ambient air pollution on the liver.

OBJECTIVES

To test the association between exposure to residential air pollution and serum biochemical indicators of liver injury.

METHODS

We used a nationally representative sample of 32,989 participants aged 3-79 years old who participated in the Canadian Health Measures Survey between 2007 and 2019. Cross-sectional associations were assessed by generalized linear mixed models incorporating survey-specific sampling weights.

RESULTS

The joint effect of an interquartile range (IQR) increase in nitrogen dioxide (NO2), ozone (O3) and fine particulate matter (PM2.5) was positively and significantly associated with all measures of liver injury adjusting for age, sex, education, income, smoking, alcohol consumption, body mass index (BMI), total cholesterol, diabetes, hypertension, and physical activity. The ranking of effect sizes from largest to smallest percent increases were 8.72% (95% confidence interval [CI] 7.56, 9.88) for alanine aminotransferase (ALT), 5.54% (95%CI 3.31, 7.77) for gamma-glutamyl transferase (GGT), 4.81% (95%CI 3.87, 5.74) for aspartate aminotransferase (AST), 2.46% (95%CI 0.26, 4.65) for total bilirubin (TBIL) and 1.18% (95%CI 0.62, 1.75) for alkaline phosphatase (ALP). Findings were not significantly different when stratified by age (≤16, >16 yr), sex, smoking (current, other), cholesterol (≤6.18, >6.18 mmol/l) and BMI (<30, ≥30 kg/m2).

DISCUSSION

These findings suggest that ambient air pollution may have a relatively small impact on the liver, but these changes may have significant impact from a population health perspective, considering the ubiquitous nature of air pollution, or for individuals exposed to very high levels of air pollution.

Short-term exposure to PM2.5 and 1.5 million deaths: a time-stratified case-crossover analysis in the Mexico City Metropolitan Area

BACKGROUND

Satellite-based PM2.5 predictions are being used to advance exposure science and air-pollution epidemiology in developed countries; including emerging evidence about the impacts of PM2.5 on acute health outcomes beyond the cardiovascular and respiratory systems, and the potential modifying effects from individual-level factors in these associations. Research on these topics is lacking in low and middle income countries. We aimed to explore the association between short-term exposure to PM2.5 with broad-category and cause-specific mortality outcomes in the Mexico City Metropolitan Area (MCMA), and potential effect modification by age, sex, and SES characteristics in such associations.

METHODS

We used a time-stratified case-crossover study design with 1,479,950 non-accidental deaths from the MCMA for the period of 2004-2019. Daily 1 × 1 km PM2.5 (median = 23.4 μg/m3; IQR = 13.6 μg/m3) estimates from our satellite-based regional model were employed for exposure assessment at the sub-municipality level. Associations between PM2.5 with broad-category (organ-system) and cause-specific mortality outcomes were estimated with distributed lag conditional logistic models. We also fit models stratifying by potential individual-level effect modifiers including; age, sex, and individual SES-related characteristics namely: education, health insurance coverage, and job categories. Odds ratios were converted into percent increase for ease of interpretation.

RESULTS

PM2.5 exposure was associated with broad-category mortality outcomes, including all non-accidental, cardiovascular, cerebrovascular, respiratory, and digestive mortality. A 10-μg/m3 PM2.5 higher cumulative exposure over one week (lag06) was associated with higher cause-specific mortality outcomes including hypertensive disease [2.28% (95%CI: 0.26%-4.33%)], acute ischemic heart disease [1.61% (95%CI: 0.59%-2.64%)], other forms of heart disease [2.39% (95%CI: -0.35%-5.20%)], hemorrhagic stroke [3.63% (95%CI: 0.79%-6.55%)], influenza and pneumonia [4.91% (95%CI: 2.84%-7.02%)], chronic respiratory disease [2.49% (95%CI: 0.71%-4.31%)], diseases of the liver [1.85% (95%CI: 0.31%-3.41%)], and renal failure [3.48% (95%CI: 0.79%-6.24%)]. No differences in effect size of associations were observed between age, sex and SES strata.

CONCLUSIONS

Exposure to PM2.5 was associated with non-accidental, broad-category and cause-specific mortality outcomes beyond the cardiovascular and respiratory systems, including specific death-causes from the digestive and genitourinary systems, with no indication of effect modification by individual-level characteristics.

Development of a lung-liver in vitro coculture model for inhalation-like toxicity assessment

Animal models are considered prime study models for inhalation-like toxicity assessment. However, in light of animal experimentation reduction (3Rs), we developed and investigated an alternative in vitro method to study systemic-like responses to inhalation-like exposures. A coculture platform was established to emulate inter-organ crosstalks between a pulmonary barrier, which constitutes the route of entry of inhaled compounds, and the liver, which plays a major role in xenobiotic metabolism. Both compartments (Calu-3 insert and HepG2/C3A biochip) were jointly cultured in a dynamically-stimulated environment for 72 h. The present model was characterized using acetaminophen (APAP), a well-documented hepatotoxicant, to visibly assess the passage and circulation of a xenobiotic through the device. Based on viability and functionality parameters the coculture model showed that the bronchial barrier and the liver biochip can successfully be maintained viable and function in a dynamic coculture setting for 3 days. In a stress-induced environment, present results reported that the coculture model emulated active and functional in vitro crosstalk that seemingly was responsive to xenobiotic exposure doses. The hepatic and bronchial cellular responses to xenobiotic exposure were modified in the coculture setting as they displayed earlier and stronger detoxification processes, highlighting active and functional organ crosstalk between both compartments.

Long-term exposure to air pollution and prevalent nonalcoholic fatty liver disease

Background

Nonalcoholic fatty liver disease (NAFLD) is a disease characterized by lipid accumulation within hepatocytes, ranging from simple steatosis to steatohepatitis, in the absence of secondary causes of hepatic fat accumulation. Although air pollution (AP) has been associated with several conditions related to NAFLD (e.g., metabolic syndrome, type 2 diabetes mellitus), few studies have explored an association between AP and NAFLD. The aim of the study was to investigate whether exposure to AP is associated with NAFLD prevalence.

Methods

We used baseline cross-sectional data (2000-2003) of the Heinz-Nixdorf-Recall cohort study in Germany (baseline n = 4,814), a prospective population-based cohort study in the urbanized Ruhr Area. Mean annual exposure to size-fractioned particulate matter (PM10, PM2.5, PMcoarse, and PM2.5abs), nitrogen dioxide, and particle number was assessed using two different exposure models: a chemistry transport dispersion model, which captures urban background AP exposure on a 1 km2 grid at participant's residential addresses, and a land use regression model, which captures point-specific AP exposure at participant's residential addresses. NAFLD was assessed with the fatty liver index (n = 4,065), with NAFLD defined as fatty liver index ≥60. We estimated ORs of NAFLD per interquartile range of exposure using logistic regression, adjusted for socio-demographic and lifestyle variables.

Results

We observed a NAFLD prevalence of 31.7% (n = 1,288). All air pollutants were positively associated with NAFLD prevalence, with an OR per interquartile range for PM2.5 of 1.11 (95% confidence interval [CI] = 1.00, 1.24) using chemistry transport model, and 1.06 (95% CI = 0.94, 1.19) using the land use regression model, respectively.

Conclusion

There was a positive association between long-term AP exposure and NAFLD.

PM2.5 exposure aggravates acute liver injury by creating an inflammatory microenvironment through Kupffer cell

AIM

This work aimed to investigate the impact of PM2.5 exposure on acute liver injury METHODS: C57BL/6 mice were used to examine the hepatic histopathological changes in PM2.5-exposed mice, as well as in CCl4-mediated acute liver injury mice after long-term exposure to PM2.5. During in vitro experiments, Kupffer cells were detected for M1 polarization level after treating with PM2.5, and the activation level of NLRP3 inflammasomes were assessed.

RESULTS

According to our findings, PM2.5 can induce M1 polarization of Kupffer cells in the liver to create an inflammatory microenvironment. Long-term exposure to PM2.5 can aggravate acute liver injury in mice. Treatment with MCC950, an NLRP3 inhibitor, can inhibit the effect of PM2.5. As demonstrated by in vitro analysis, PM2.5 can promote M1 polarization of Kupffer cells.

CONCLUSION

As suggested by our results, long-term exposure to PM2.5 can create an inflammatory microenvironment to aggravate mouse acute liver injury. The effect is related to NLRP3-mediated M1 polarization in Kupffer cells.

PM2.5 induced liver lipid metabolic disorders in C57BL/6J mice

PM2.5 can cause adverse health effects via several pathways, such as inducing pulmonary and systemic inflammation, penetration into circulation, and activation of the autonomic nervous system. In particular, the impact of PM2.5 exposure on the liver, which plays an important role in metabolism and detoxification to maintain internal environment homeostasis, is getting more attention in recent years. In the present study, C57BL/6J mice were randomly assigned and treated with PM2.5 suspension and PBS solution for 8 weeks. Then, hepatic tissue was prepared and identified by metabolomics analysis and transcriptomics analysis. PM2.5 exposure can cause extensive metabolic disturbances, particularly in lipid and amino acids metabolic dysregulation.128 differential expression metabolites (DEMs) and 502 differently expressed genes (DEGs) between the PM2.5 exposure group and control group were detected. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that DEGs were significantly enriched in two disease pathways, non-alcoholic fatty liver disease (NAFLD) and type II diabetes mellitus (T2DM), and three signaling pathways, which are TGF-beta signaling, AMPK signaling, and mTOR signaling. Besides, further detection of acylcarnitine levels revealed accumulation in liver tissue, which caused restricted lipid consumption. Furthermore, lipid droplet accumulation in the liver was confirmed by Oil Red O staining, suggesting hepatic steatosis. Moreover, the aberrant expression of three key transcription factors revealed the potential regulatory effects in lipid metabolic disorders, the peroxisomal proliferative agent-activated receptors (PPARs) including PPARα and PPARγ is inhibited, and the activated sterol regulator-binding protein 1 (SREBP1) is overexpressed. Our results provide a novel molecular and genetic basis for a better understanding of the mechanisms of PM2.5 exposure-induced hepatic metabolic diseases, especially in lipid metabolism.

Short-Term Exposure to PM2.5 and O3 Impairs Liver Function in HIV/AIDS Patients: Evidence from a Repeated Measurements Study

Studies investigating the relationship between ambient air pollutants and liver function are scarce. Our objective was to examine the associations of acute exposure to PM2.5 and O3 with levels of hepatic enzymes in people living with HIV/AIDS (PWHA). Our study involved 163 PWHA, who were evaluated for serum hepatic enzymes up to four times within a year. We extracted daily average concentrations of PM2.5, PM2.5 components, and O3 for each participant, based on their residential address, using the Tracking of Air Pollution in China database. Linear mixed-effect models were utilized to assess the associations of acute exposure to PM2.5 and O3 with hepatic enzymes. Weighted quantile sum regression models were employed to identify the major constituents of PM2.5 that affect hepatic enzymes. The percent change of aspartate aminotransferase (AST) concentration was positively correlated with a 10 µg/m3 increase in PM2.5, ranging from 1.92 (95% CI: 3.13 to 4.38) to 6.09 (95% CI: 9.25 to 12.38), with the largest effect observed at lag06. Additionally, acute O3 exposure was related to increased levels of alanine aminotransferase (ALT), AST, and alkaline phosphatase (ALP) concentrations. Co-exposure to high levels of PM2.5 and O3 had an antagonistic effect on the elevation of AST. Further analysis revealed that SO42- and BC were major contributors to elevated AST concentration due to PM2.5 constituents. A stronger association was found between O3 exposure and ALT concentration in female PWHA. Our study found that short-term exposure to PM2.5 and O3 was associated with increased levels of hepatic enzymes, indicating that PM2.5 and O3 exposure may contribute to hepatocellular injury in PWHA. Our study also found that PWHA may be more vulnerable to air pollution than the general population. These findings highlight the relationship between air pollutants and liver function in PWHA, providing a scientific basis for the implementation of measures to protect susceptible populations from the adverse effects of air pollution. A reduction in the burning of fossil fuels and reduced exposure to air pollutants may be effective hazard reduction approaches.

Histological features of non-alcoholic fatty liver disease revealed in response to mixed vehicle emission exposure and consumption of a high-fat diet in wildtype C57Bl/6 male mice

Non-alcoholic fatty liver disease (NAFLD) is currently plaguing the population at pandemic proportions and is expected to become more prevalent over the next decade. Recent epidemiological studies have demonstrated a correlation between the manifestation of NAFLD and ambient air pollution levels, which is exacerbated by other risk factors, such as diabetes, dyslipidemia, obesity, and hypertension. Exposure to airborne particulate matter has also been associated with inflammation, hepatic lipid accumulation, oxidative stress, fibrosis, and hepatocyte injury. While prolonged consumption of a high-fat (HF) diet is associated with NAFLD, little is known regarding the effects of inhaled traffic-generated air pollution, a ubiquitous environmental pollutant, on the pathogenesis of NAFLD. Therefore, we investigated the hypothesis that exposure to a mixture of gasoline and diesel engine emissions (MVE), coupled with the concurrent consumption of a HF diet, promotes the development of a NAFLD phenotype within the liver. Three-month-old male C57Bl/6 mice were placed on either a low-fat or HF diet and exposed via whole-body inhalation to either filtered (FA) air or MVE (30 µg PM/m3 gasoline engine emissions + 70 µg PM/m3 diesel engine emissions) 6 hr/day for 30 days. Histology revealed mild microvesicular steatosis and hepatocyte hypertrophy in response to MVE exposure alone, compared to FA controls, yielding a classification of "borderline NASH" under the criteria of the modified NAFLD active score (NAS) system. As anticipated, animals on a HF diet exhibited moderate steatosis; however, we also observed inflammatory infiltrates, hepatocyte hypertrophy, and increased lipid accumulation, with the combined effect of HF diet and MVE exposure. Our results indicate that inhalation exposure to traffic-generated air pollution initiates hepatocyte injury and further exacerbates lipid accumulation and hepatocyte injury induced by the consumption of a HF diet, thereby contributing to the progression of NAFLD-related pathologies.

Air pollution, alcohol consumption, and the risk of elevated liver enzyme levels: a cross-sectional study in the UK Biobank

Evidences on the association between exposure to air pollution and liver enzymes was scarce in low pollution area. We aimed to investigate the association between air pollution and liver enzyme levels and further explore whether alcohol intake influence this association. This cross-sectional study included 425,773 participants aged 37 to 73 years from the UK Biobank. Land Use Regression was applied to assess levels of PM2.5, PM10, NO2, and NOx. Levels of liver enzymes including AST, ALT, GGT, and ALP were determined by enzymatic rate method. Long-term low-level exposure to PM2.5 (per 5-μg/m3 increase) was significantly associated with AST (0.596% increase, 95% CI, 0.414 to 0.778%), ALT (0.311% increase, 0.031 to 0.593%), and GGT (1.552% increase, 1.172 to 1.933%); The results were similar for PM10; NOX and NO2 were only significantly correlated with AST and GGT Significant modification effects by alcohol consumption were found (P-interaction < 0.05). The effects of pollutants on AST, ALT, and GGT levels gradually increased along with the weekly alcohol drinking frequency. In conclusion, long-term low-level air pollutants exposure was associated with elevated liver enzyme levels. And alcohol intake may exacerbate the effect of air pollution on liver enzymes.

The effect of PM2.5 exposure on the mortality of patients with hepatocellular carcinoma in Tianjin, China

Several studies have shown the effects of PM_2.5 exposure on respiratory and cardiovascular systems. However, there is no cohort study evidence of adverse effects of PM_2.5 exposure on survival in patients with hepatocellular carcinoma (HCC) in China. This study is aimed at evaluating this association. This cohort study included 1440 HCC patients treated at the Third Central Clinical College of Tianjin Medical University from September 2013 to December 2018. We collected patient information, including demographic data, medical history, lifestyle characteristics, and disease characteristics. Based on PM_2.5 concentrations measured at monitoring stations, the inverse distance weighted (IDW) method was used to assess the individuals' exposure during their survival period. Survival status was analysed by the Kaplan-Meier method. Restricted cubic splines and Cox proportional hazards models were used to estimate the relationship between PM_2.5 and mortality, and potential confounders were adjusted for. The mortality rate of HCC patients exposed to PM_2.5 ≥ 58.56 μg/m³ was significantly higher than that of HCC patients living in environments with PM_2.5 < 58.56 μg/m³ (79.0% vs 50.7%, P < 0.001). The restricted cubic spline model showed a linear relationship between the PM_2.5 concentration and mortality risk (P overall-association < 0.0001 and P nonlinear-association = 0.3568). Cox regression analysis showed that after adjusting for confounding factors, for every 10-μg/m³ increase in atmospheric PM_2.5, the risk of death for HCC patients increased by 44% [hazard ratio (HR) = 1.44, 95% confidence interval (CI) 1.34, 1.56; P < 0.001]. Compared with patients exposed to PM_2.5 <58.56 μg/m³, those exposed to PM_2.5 ≥ 58.56 μg/m³ had a 1.55-fold increased risk of death. Stratified analysis results showed that the effects of PM_2.5 on HCC mortality were more significant in patients aged ≥60 years or patients living in central urban areas. We found that exposure to elevated PM_2.5 after HCC diagnosis may affect survival, with a higher concentration corresponding to a greater effect.

The protective effect of p-Coumaric acid on hepatic injury caused by particulate matter in the rat and determining the role of long noncoding RNAs MEG3 and HOTAIR

Increasing air pollution is associated with serious human health problems. P-coumaric acid (PC) is a herbal phenolic compound that exhibits beneficial pharmacological potentials. Here, the protective effect of PC on liver injury induced by air pollution was examined. Thirty-two adult male Wistar rats (200-250 g) were divided randomly into four groups (n = 8). The groups were; Control (rats received DMSO and then exposed to clean air), PC (rats received PC and then exposed to clean air), DMSO + Dust (rats received DMSO and then exposed to dust), and PC + Dust (the animals received PC and then exposed to dust). The clean air, DMSO, PC, and dust were administrated 3 days a week for 6 consecutive weeks. The rats were anesthetized and their blood samples and liver sections were taken to conduct molecular, biomedical, and histopathological tests. Dust exposure increased the liver enzymes, bilirubin, triglyceride, cholesterol, and the production of liver malondialdehyde, and decreased in liver total anti-oxidant capacity and serum high-density lipoprotein. It also increased the mRNA expression of inflammatory-related cytokines, decreased the mRNA expression of SIRT-1, decreased the expression levels of miR-20b5p, and MEG3 while increased the expression levels of miR-34a, and HOTAIR. Dust exposure also increased the liver content of three cytokines TNF-α, NF-κB, HMGB-1, and ATG-7 proteins. PC enhanced liver function against adverse effects of dust through recovering almost all the studied variables. Exposure to dust damaged the liver through induction of oxidative stress, inflammation, and autophagy. PC protected the liver against dust-induced cytotoxicity.

Emerging epigenetic dynamics in gut-microglia brain axis: experimental and clinical implications for accelerated brain aging in schizophrenia

Brain aging, which involves a progressive loss of neuronal functions, has been reported to be premature in probands affected by schizophrenia (SCZ). Evidence shows that SCZ and accelerated aging are linked to changes in epigenetic clocks. Recent cross-sectional magnetic resonance imaging analyses have uncovered reduced brain reserves and connectivity in patients with SCZ compared to typically aging individuals. These data may indicate early abnormalities of neuronal function following cyto-architectural alterations in SCZ. The current mechanistic knowledge on brain aging, epigenetic changes, and their neuropsychiatric disease association remains incomplete. With this review, we explore and summarize evidence that the dynamics of gut-resident bacteria can modulate molecular brain function and contribute to age-related neurodegenerative disorders. It is known that environmental factors such as mode of birth, dietary habits, stress, pollution, and infections can modulate the microbiota system to regulate intrinsic neuronal activity and brain reserves through the vagus nerve and enteric nervous system. Microbiota-derived molecules can trigger continuous activation of the microglial sensome, groups of receptors and proteins that permit microglia to remodel the brain neurochemistry based on complex environmental activities. This remodeling causes aberrant brain plasticity as early as fetal developmental stages, and after the onset of first-episode psychosis. In the central nervous system, microglia, the resident immune surveillance cells, are involved in neurogenesis, phagocytosis of synapses and neurological dysfunction. Here, we review recent emerging experimental and clinical evidence regarding the gut-brain microglia axis involvement in SCZ pathology and etiology, the hypothesis of brain reserve and accelerated aging induced by dietary habits, stress, pollution, infections, and other factors. We also include in our review the possibilities and consequences of gut dysbiosis activities on microglial function and dysfunction, together with the effects of antipsychotics on the gut microbiome: therapeutic and adverse effects, role of fecal microbiota transplant and psychobiotics on microglial sensomes, brain reserves and SCZ-derived accelerated aging. We end the review with suggestions that may be applicable to the clinical setting. For example, we propose that psychobiotics might contribute to antipsychotic-induced therapeutic benefits or adverse effects, as well as reduce the aging process through the gut-brain microglia axis. Overall, we hope that this review will help increase the understanding of SCZ pathogenesis as related to chronobiology and the gut microbiome, as well as reveal new concepts that will serve as novel treatment targets for SCZ.

Exposure to ambient air pollution and elevated blood levels of gamma-glutamyl transferase in a large Austrian cohort

Gamma glutamyl transferase (GGT) is related to oxidative stress and an indicator for liver damage. We investigated the association between air pollution and GGT in a large Austrian cohort (N = 116,109) to better understand how air pollution affects human health. Data come from voluntary prevention visits that were routinely collected within the Vorarlberg Health Monitoring and Prevention Program (VHM&PP). Recruitment was ongoing from 1985 to 2005. Blood was drawn and GGT measured centralized in two laboratories. Land use regression models were applied to estimate individuals' exposure at their home address for particulate matter (PM) with a diameter of <2.5 μm (PM2.5), <10 μm (PM10), fraction between 10 μm and 2.5 μm (PMcoarse), as well as PM2.5 absorbance (PM2.5abs), NO₂, NO_x and eight components of PM. Linear regression models, adjusting for relevant individual and community-level confounders were calculated. The study population was 56 % female with a mean age of 42 years and mean GGT was 19.0 units. Individual PM2.5 and NO₂ exposures were essentially below European limit values of 25 and 40 μg/m³, respectively, with means of 13.58 μg/m³ for PM2.5 and 19.93 μg/m³ for NO₂. Positive associations were observed for PM2.5, PM10, PM2.5abs, NO₂, NO_x, and Cu, K, S in PM2.5 and PM10 fractions and Zn mainly in PM2.5 fraction. The strongest association per interquartile range observed was an increase of serum GGT concentration by 1.40 % (95 %-CI: 0.85 %; 1.95 %) per 45.7 ng/m³ S in PM2.5. Associations were robust to adjustments for other biomarkers, in two-pollutant models and the subset with a stable residential history. We found that long-term exposure to air pollution (PM2.5, PM10, PM2.5abs, NO₂, NO_x) as well as certain elements, were positively associated with baseline GGT levels. The elements associated suggest a role of traffic emissions, long range transport and wood burning.

Measurement and control of containing-fluorine particulate matter emission during spent pot lining combustion detoxification process

The particle size distribution (PSD), composition, morphology, and formation mechanism of particulate matter (PM) released from the combustion of spent pot lining with and without CaSiO₃ were investigated. The results showed that NaF and Na₃AlF₆ were found to be the main compositions of PM, and the particle size distribution of PM shows a bimodal distribution. CaSiO₃ substantially inhibited the emission of PM by transforming NaF, Na₃AlF₆, and CaF₂ into stable Ca₄Si₂O₇F₂. Moreover, CaSiO₃ also limited the formation of high hazardous PM_0.2 by providing SiO₂, Al₂O₃, and NaAlSiO₄ with high melting points as the core of promoting the growth of PM in particle size.

Self-Reported Primary Cooking Fuels Use and Risk of Chronic Digestive Diseases: A Prospective Cohort Study of 0.5 Million Chinese Adults

BACKGROUND

Household air pollution (HAP) from inefficient combustion of solid fuels is a major health concern worldwide. However, prospective evidence on the health impacts of solid cooking fuels and risks of chronic digestive diseases remains scarce.

OBJECTIVES

We explored the effects of self-reported primary cooking fuels on the incidence of chronic digestive diseases.

METHODS

The China Kadoorie Biobank recruited 512,726 participants 30-79 years of age from 10 regions across China. Information on primary cooking fuels at the current and previous two residences was collected via self-reporting at baseline. Incidence of chronic digestive diseases was identified through electronic linkage and active follow-up. Cox proportional hazards regression models were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of self-reported long-term cooking fuel patterns and weighted duration of self-reported solid cooking fuel use with chronic digestive diseases incidence. Linear trend was tested by assigning the medians of weighted duration in each group and then taking those as continuous variables in the models. Subgroup analyses were undertaken across the baseline characteristics of participants.

RESULTS

During 9.1 ± 1.6 y of follow-up, 16,810 new cases of chronic digestive diseases were documented, among which 6,460 were diagnosed as cancers. Compared with long-term cleaner fuel use, self-reported long-term use of solid cooking fuels (i.e., coal, wood) was associated with elevated risks of chronic digestive diseases (HR = 1.08 ; 95% CI: 1.02, 1.13), including nonalcoholic fatty liver disease (NAFLD) (HR = 1.43 ; 95% CI: 1.10, 1.87), hepatic fibrosis/cirrhosis (HR = 1.35 ; 95% CI: 1.05, 1.73), cholecystitis (HR = 1.19 ; 95% CI: 1.07, 1.32), and peptic ulcers (HR = 1.15 ; 95% CI: 1.00, 1.33). The longer the weighted duration of self-reported solid cooking fuel use, the higher the risks of chronic digestive diseases, hepatic fibrosis/cirrhosis, peptic ulcers, and esophageal cancer (p Trend < 0.05 ). The aforementioned associations were modified by sex and body mass index (BMI). Positive associations of always solid cooking fuel use with chronic digestive disease, hepatic fibrosis/cirrhosis, NAFLD, and cholecystitis were observed among women but not men. The longer the weighted duration of self-reported solid cooking fuel use, the higher the risk of NAFLD among those with a BMI ≥ 28   kg / m 2 .

DISCUSSION

Long-term self-reported solid cooking fuels use was associated with higher risks of chronic digestive diseases. The positive association of HAP from solid cooking fuels with chronic digestive diseases indicates for an imminent promotion of cleaner fuels as public health interventions. https://doi.org/10.1289/EHP10486.

State of the science on outdoor air pollution exposure and liver cancer risk

Background

There is emerging evidence that air pollution exposure increases the risk of developing liver cancer. To date, there have been four epidemiologic studies conducted in the United States, Taiwan, and Europe showing generally consistent positive associations between ambient exposure to air pollutants, including particulate matter <2.5 μm in aerodynamic diameter (PM2.5) and nitrogen dioxide (NO2), and liver cancer risk. There are several research gaps and thus valuable opportunities for future work to continue building on this expanding body of literature. The objectives of this paper are to narratively synthesize existing epidemiologic literature on the association between air pollution exposure and liver cancer incidence and describe future research directions to advance the science of understanding the role of air pollution exposure in liver cancer development.

Future research directions

include 1) accounting for potential confounding by established risk factors for the predominant histological subtype, hepatocellular carcinoma (HCC); 2) examination of incident primary liver cancer outcomes with consideration of potential differential associations according to histology; 3) air pollution exposure assessments considering early-life and/or historical exposures, residential histories, residual confounding from other sources of air pollution (e.g., tobacco smoking), and integration of geospatial ambient exposure modeling with novel biomarker technologies; 4) examination of air pollution mixtures experienced in the exposome; 5) consideration of increased opportunities for exposure to outdoor air pollution due to climate change (e.g., wildfires); and 6) consideration of modifying factors for air pollution exposure, such as socioeconomic status, that may contribute to disparities in liver cancer incidence.

Conclusions

In light of mounting evidence demonstrating that higher levels of air pollution exposure increase the risk for developing liver cancer, methodological considerations primarily concerning residual confounding and improved exposure assessment are warranted to robustly demonstrate an independent association for air pollution as a hepatocarcinogen.

Risk of death from liver cancer in relation to long-term exposure to fine particulate air pollution in Taiwan

According to the International Agency for Research on Cancer (IARC), airborne fine particulate matter (PM_2.5), which is categorized as a Group I carcinogen, was found to lead to predominantly lung as well as other cancer types in humans. Hepatocellular carcinoma (HCC) is endemic in Taiwan where it is the second and fourth foremost cause of cancer deaths in men and women, respectively. Taiwan's mortality rates for liver cancer vary considerably from one region to another, suggesting that the environment may exert some influence on deaths attributed to liver cancer. The aim of this investigation was to perform an ecologic study to examine the possible link between ambient PM_2.5 levels and risk of liver cancer in 66 in Taiwan municipalities. To undertake this investigation, annual PM_2.5 levels and age-standardized liver cancer mortality rates were calculated for male and female residents of these areas from 2010 to 2019. Data were tested using weighted-multiple regression analyses to compute adjusted risk ratio (RR) controlling for urbanization level and physician density. Annual PM_2.5 levels of each municipality were divided into tertiles. The adjusted RRs for males residing in those areas with intermediate tertile levels (21.85 to 28.21 ug/m³) and the highest tertiles levels (28.22-31.23 ug/m³) of PM_2.5 were 1.29 (95% CI = 1.25-1.46) and 1.41 (95% CI = 1.36-1.46), respectively. Women in these locations shared a similar risk, 1.32 (1.25-1.4) and 1.41 (1.34-1.49), respectively. Evidence indicated that PM_2.5 increased risk of mortality rates attributed to liver cancer in both men and women in Taiwan.

Daily exposure to PM2.5 and 1.5 million deaths: A time-stratified case-crossover analysis in the Mexico City Metropolitan Area

Background

Satellite-based PM2.5 predictions are being used to advance exposure science and air-pollution epidemiology in developed countries; including emerging evidence about the impacts of PM2.5 on acute health outcomes beyond the cardiovascular and respiratory systems, and the potential modifying effects from individual-level factors in these associations. Research on these topics is lacking in Latin America.

Methods

We used a time-stratified case-crossover study design with 1,479,950 non-accidental deaths from Mexico City Metropolitan Area for the period of 2004-2019. Daily 1×1 km PM2.5 (median=23.4 μg/m3; IQR=13.6 μg/m3) estimates from our satellite-based regional model were employed for exposure assessment at the sub-municipality level. Associations between PM2.5 with broad-category (organ-system) and cause-specific mortality outcomes were estimated with distributed lag conditional logistic models. We also fit models stratifying by potential individual-level effect modifiers including; age, sex, and individual SES-related characteristics namely: education, health insurance coverage, and job categories.

Results

PM2.5 exposure was associated with higher total non-accidental, cardiovascular, cerebrovascular, respiratory, and digestive mortality. A 10-μg/m3 PM2.5 higher cumulative exposure over one week (lag06) was associated with higher cause-specific mortality outcomes including hypertensive disease [2.28% (95%CI: 0.26%-4.33%)], acute ischemic heart disease [1.61% (95%CI: 0.59%-2.64%)], other forms of heart disease [2.39% (95%CI: -0.35%-5.20%)], hemorrhagic stroke [3.63% (95%CI: 0.79%-6.55%)], influenza and pneumonia [4.91% (95%CI: 2.84%-7.02%)], chronic respiratory disease [2.49% (95%CI: 0.71%-4.31%)], diseases of the liver [1.85% (95%CI: 0.31%-3.41%)], and renal failure [3.48% (95%CI: 0.79%-6.24%)]. No differences in effect size of associations were observed between SES strata.

Conclusions

Exposure to PM2.5 was associated with mortality outcomes beyond the cardiovascular and respiratory systems, including specific death-causes from the digestive and genitourinary systems, with no indications of effect modification by individual SES-related characteristics.

Association of greenness exposure with coronary artery stenosis and biomarkers of myocardial injury in patients with myocardial infarction

BACKGROUND

Greenness has been linked to cardiovascular health; however, limited evidence is available regarding its association with coronary artery stenosis and biomarkers of myocardial injury. We aimed to assess these associations and examine their modification and mediation effects in patients with myocardial infarction (MI).

METHODS

This study included 2030 patients with MI. The normalized difference vegetation index (NDVI) was used to characterize greenness exposure. We used a logistic regression model to explore the relationship between coronary artery stenosis and residential greenness, and applied linear regression models to assess the association of greenness with biomarkers of myocardial injury. The bootstrap method was used to explore whether potential variables mediated the associations. To further investigate the exposure-response curve describing these relationships, we developed restricted cubic spline models.

RESULT

Compared to the lowest quartile of NDVI, the odds ratio (OR) (95 % confidence interval [CI]) for severe stenosis (≥75 % stenosis) was 0.68 (95 % CI: 0.47 to 0.98) for the third quartile. Participants in the highest greenness exposure quartile had lower levels of cardiac troponin I (cTnI), creatine kinase (CK), and creatine kinase isoenzyme (CKMB) than those in the lowest quartile (β = -0.22, 95 % CI: -0.40 to -0.05; β = -0.13, 95 % CI: -0.22 to -0.04; β = -0.07, 95 % CI: -0.14 to -0.003). The association between residential greenness and myocardial injury biomarkers was stronger in men and older participants. Mediation analyses revealed that the effects of greenness on coronary stenosis, cTnI, CK, and CKMB were mediated by systolic blood pressure (SBP) and diastolic blood pressure (DBP).

CONCLUSION

Higher greenness exposure was associated with coronary artery stenosis and reduced levels of myocardial injury biomarkers, including cTnI, CK, and CKMB. These associations may be partially mediated by SBP and DBP levels.

CO2 in indoor environments: From environmental and health risk to potential renewable carbon source

In the developed world, individuals spend most of their time indoors. Poor Indoor Air Quality (IAQ) has a wide range of effects on human health. The burden of disease associated with indoor air accounts for millions of premature deaths related to exposure to Indoor Air Pollutants (IAPs). Among them, CO₂ is the most common one, and is commonly used as a metric of IAQ. Indoor CO₂ concentrations can be significantly higher than outdoors due to human metabolism and activities. Even in presence of ventilation, controlling the CO₂ concentration below the Indoor Air Guideline Values (IAGVs) is a challenge, and many indoor environments including schools, offices and transportation exceed the recommended value of 1000 ppm_v. This is often accompanied by high concentration of other pollutants, including bio-effluents such as viruses, and the importance of mitigating the transmission of airborne diseases has been highlighted by the COVID-19 pandemic. On the other hand, the relatively high CO₂ concentration of indoor environments presents a thermodynamic advantage for direct air capture (DAC) in comparison to atmospheric CO₂ concentration. This review aims to describe the issues associated with poor IAQ, and to demonstrate the potential of indoor CO₂ DAC to purify indoor air while generating a renewable carbon stream that can replace conventional carbon sources as a building block for chemical production, contributing to the circular economy.

Can Maternal Exposure to Air Pollution Affect Post-Natal Liver Development?

Emerging evidence suggests that inhalation of particulate matter (PM) can have direct adverse effects on liver function. Early life is a time of particular vulnerability to the effects of air pollution. On that basis, we tested whether in utero exposure to residential PM has an impact on the developing liver. Pregnant mice (C57BL/6J) were intranasally administered 100 µg of PM sampled from residential roof spaces (~5 mg/kg) on gestational days 13.5, 15.5, and 17.5. The pups were euthanized at two weeks of age, and liver tissue was collected to analyse hepatic metabolism (glycogen storage and lipid level), cellular responses (oxidative stress, inflammation, and fibrosis), and genotoxicity using a range of biochemical assays, histological staining, ELISA, and qPCR. We did not observe pronounced effects of environmentally sampled PM on the developing liver when examining hepatic metabolism and cellular response. However, we did find evidence of liver genomic DNA damage in response to in utero exposure to PM. This effect varied depending on the PM sample. These data suggest that in utero exposure to real-world PM during mid-late pregnancy has limited impacts on post-natal liver development.

Interactive effects of ambient air pollution and sunshine duration on the risk of intrahepatic cholestasis of pregnancy

INTRODUCTION

While the associations among ambient pollutants and various pregnancy complications are well documented, the effect of ambient pollutants on intrahepatic cholestasis of pregnancy (ICP) has not been examined. This study aimed to explore the effects of ambient pollutants and sunshine duration on ICP.

METHODS

The study enrolled 169,971 pregnant women who delivered between 2015 and 2020 in two hospitals. The associations between ICP and exposure to ambient pollutants and sunshine duration, averaged throughout different periods (including the 3 months before conception, 1st trimester and 2nd trimester), were estimated using a generalized linear model. The interaction effects of ambient pollutants and sunshine duration on ICP were estimated.

RESULTS

The fitted curves for ICP incidence were similar to the temporal trends of PM_2.5, PM₁₀, SO₂, CO and NO₂ but not that of O₃. The risk of ICP was significantly elevated following a 10-μg/m³ increase in PM_2.5 (aOR [adjusted odds ratio] = 1.057, 95% CI [confidence interval]: 1.017-1.099) and PM₁₀ (aOR = 1.043, 95% CI: 1.013-1.074) and a 1-h decrease in sunshine duration (aOR = 1.039, 95% CI: 1.011-1.068) during the 3 months before conception. In the second trimester, a 1-μg/m³ increase in the concentration of SO₂ was associated with an increased risk of ICP (aOR = 1.011, 95% CI: 1.001-1.021). Increased concentrations of PM_2.5 and PM₁₀ had interactive effects with reduced sunshine duration during the 3 months before conception on increasing the risk of ICP.

CONCLUSIONS

Exposure to PM_2.5 and PM₁₀ during the 3 months before conception and exposure to SO₂ in the second trimester were associated with an increased ICP risk. Reduced sunshine duration had an interactive effect with increased concentrations of PM_2.5 and PM₁₀ during the 3 months before conception on the occurrence of ICP.

Kidney damage induced by repeated fine particulate matter exposure: Effects of different components

BACKGROUND

Exposure to fine particulate matter with an aerodynamic diameter of ≤2.5 μm (PM_2.5) is associated with adverse health effects. This study aimed to evaluate the toxic effects of the constituents of PM_2.5 on mouse kidneys.

METHODS

We collected PM_2.5 near an industrial complex located in southern Kaohsiung, Taiwan, that was divided into water extract and insoluble particles. Male C57BL/6 mice were divided into five groups: control, low- and high-dose insoluble particle exposure, and low- and high-dose water extract exposure. Biochemical analysis, Western blot analysis, histological examination, and immunohistochemistry were performed to evaluate the impact of PM_2.5 constituents on mice kidneys.

RESULTS

PM_2.5 was collected from January 1, 2021, to February 8, 2021, from an industrial complex in Kaohsiung, Taiwan. Metallic element analysis showed that Pb, Ni, V, and Ti were non-essential metals with enrichment factors >10. Polycyclic aromatic hydrocarbon and nitrate polycyclic aromatic hydrocarbon analyses revealed that the toxic equivalents are, in the order, benzo(a)pyrene (BaP), indeno(1,2,3-cd) pyrene (IP), dibenzo(a,h)anthracene (DBA), and benzo(b)fluoranthene (BbF), which are potential carcinogens. Both water extract and insoluble particle exposure induced inflammatory cytokine upregulation, inflammatory cell infiltration, antioxidant activity downregulation, and elevation of kidney injury molecule 1 (KIM-1) level in mouse kidneys. A dose-dependent effect of PM_2.5 water extract and insoluble particle exposure on angiotensin converter enzyme 2 downregulation in mouse kidneys was observed.

CONCLUSION

We found that water-soluble extract and insoluble particles of PM_2.5 could induce oxidative stress and inflammatory reactions, influence the regulation of renin-angiotensin system (RAS), and lead to kidney injury marker level elevation in mouse kidneys. The lowest-observed-adverse-effect level for renal toxicity in mice was 40 μg water-soluble extract/insoluble particle inhalation per week, which was approximately equal to the ambient PM_2.5 concentration of 44 μg/m³ for mice.

Sex-Dependent Responses to Maternal Exposure to PM2.5 in the Offspring

Objective: Particulate matter (PM) with a diameter of 2.5 μm or less (PM_2.5) can cross the blood-placental barrier causing adverse foetal outcomes. However, the impact of maternal exposure to low-levels of PM_2.5 on liver health and the metabolic profile is unclear. This study aimed to investigate hepatic responses to long-term gestational low-dose PM_2.5 exposure, and whether the removal of PM after conception can prevent such effects. Method: Female Balb/c mice (8 weeks) were exposed to PM_2.5 (5 μg/day) for 6 weeks prior to mating, during gestation and lactation to model living in a polluted environment (PM group). In a sub-group, PM_2.5 exposure was stopped post-conception to model mothers moving to areas with clean air (pre-gestation, Pre) group. Livers were studied in 13-week old offspring. Results: Female offspring in both PM and Pre groups had increased liver triglyceride and glycogen levels, glucose intolerance, but reduced serum insulin and insulin resistance. Male offspring from only the Pre group had increased liver and serum triglycerides, increased liver glycogen, glucose intolerance and higher fasting glucose level. Markers of oxidative stress and inflammation were increased in females from PM and Pre groups. There was also a significant sex difference in the hepatic response to PM_2.5 with differential changes in several metabolic markers identified by proteomic analysis. Conclusions: Maternal PM exposure exerted sex-dependent effects on liver health with more severe impacts on females. The removal of PM_2.5 during gestation provided limited protection in the offspring’s metabolism regardless of sex.

Long-term nonlinear relationship between PM2.5 and ten leading causes of death

Air pollution has become a major concern worldwide. Many epidemiological studies have proved relationships between fine particulate matter (PM_2.5) and various diseases, but most studies only use short-term and models for specific groups to derive relationships with acute diseases. This makes it difficult to understand long-term exposure, nonlinear relationships, and spatial-temporal health risks regarding chronic diseases. Therefore, this study proposed to analyze and map PM_2.5 exceedance probability from long-term spatial-temporal monitoring data using radial basis function estimation. We then constructed and compared multiple linear regression and generalized additive models to investigate linear and nonlinear relationships between long-term average PM_2.5 concentration, PM_2.5 potential probability for exceeding the standard, and standardized mortality for the top ten causes of death in all towns and villages in Taiwan nationally from 2010 to 2017. Linear models indicate that increasing PM_2.5 concentration increased malignant neoplasm, pneumonia, and chronic lower respiratory disease mortalities; chronic liver diseases; and cirrhosis; whereas heart diseases and esophagus cancer mortality decreased. For the nonlinear model results, it can be found that there were also significant nonlinear relationships between PM_2.5 concentration and malignant mortalities for neoplasm, heart disease, diabetes; and trachea, bronchus, lung, liver, intrahepatic bile duct, and esophagus cancer. Thus, long-term exposure to PM_2.5 may be a significant risk factor for multiple acute and chronic diseases. Results from this study can be directly applied worldwide to provide air quality and health management references for governments, and important information on long-term health risks for local residents in the study area.

Environmental Stressors and the PINE Network: Can Physical Environmental Stressors Drive Long-Term Physical and Mental Health Risks?

Both psychosocial and physical environmental stressors have been linked to chronic mental health and chronic medical conditions. The psycho-immune-neuroendocrine (PINE) network details metabolomic pathways which are responsive to varied stressors and link chronic medical conditions with mental disorders, such as major depressive disorder via a network of pathophysiological pathways. The primary objective of this review is to explore evidence of relationships between airborne particulate matter (PM, as a concrete example of a physical environmental stressor), the PINE network and chronic non-communicable diseases (NCDs), including mental health sequelae, with a view to supporting the assertion that physical environmental stressors (not only psychosocial stressors) disrupt the PINE network, leading to NCDs. Biological links have been established between PM exposure, key sub-networks of the PINE model and mental health sequelae, suggesting that in theory, long-term mental health impacts of PM exposure may exist, driven by the disruption of these biological networks. This disruption could trans-generationally influence health; however, long-term studies and information on chronic outcomes following acute exposure event are still lacking, limiting what is currently known beyond the acute exposure and all-cause mortality. More empirical evidence is needed, especially to link long-term mental health sequelae to PM exposure, arising from PINE pathophysiology. Relationships between physical and psychosocial stressors, and especially the concept of such stressors acting together to impact on PINE network function, leading to linked NCDs, evokes the concept of syndemics, and these are discussed in the context of the PINE network.

PM2.5 air pollution exposure and nonalcoholic fatty liver disease in the Nationwide Inpatient Sample

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. Particulate matter air pollution <2.5 μm in diameter (PM_2.5) is a ubiquitous exposure primarily produced from fossil fuel combustion. Previous epidemiologic studies have been mixed. The objective of this study was to examine the association between ambient PM_2.5 exposure and NAFLD among hospitalized patients in the Nationwide Inpatient Sample (NIS).

METHODS

We conducted a cross-sectional analysis of hospitalizations from 2001 to 2011 using the NIS, the largest nationally representative all-payer inpatient care administrative database in the United States. Average annual PM_2.5 exposure was estimated by linking census tracts (based on NIS-provided hospital ZIP Codes) with a spatiotemporal exposure model. Clinical conditions were identified using hospital discharge diagnosis codes. Multivariable logistic regression incorporating discharge weights was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between PM_2.5 exposure and odds of NAFLD among hospitalized patients adjusting for age, sex, race/ethnicity, year, individual- and area-level socioeconomic status, urbanicity, region, obesity, diabetes, metabolic syndrome, impaired fasting glucose, dyslipidemia, hypertension, obstructive sleep apnea, and smoking.

RESULTS

There were 269,705 hospitalized patients with NAFLD from 2001 to 2011 (total unweighted n = 45,433,392 hospitalizations). Higher ambient PM_2.5 exposure was associated with increased odds of NAFLD among hospitalized patients (adjusted OR: 1.24 per 10 μg/m³ increase, 95% CI 1.15-1.33, p < 0.01). There were statistically significant interactions between PM_2.5 exposure and age, race/ethnicity, diabetes, smoking, and region, with stronger positive associations among patients who were aged ≥45 years, non-Hispanic White or Asian/Pacific Islander, non-diabetics, non-smokers, or in the Midwest and West regions, respectively.

CONCLUSIONS

In this nationwide cross-sectional analysis of the NIS database, there was a positive association between ambient PM_2.5 exposure and odds of NAFLD among hospitalized patients. Future research should examine the effects of long-term historical PM_2.5 exposure and incident NAFLD cases.

Role of Liver Enzymes in the Relationship Between Particulate Matter Exposure and Diabetes Risk: A Longitudinal Cohort Study

CONTEXT

Particulate matter (PM) is an important risk factor for diabetes. However, its underlying mechanisms remain poorly understood. Although liver-derived biological intermediates may play irreplaceable roles in the pathophysiology of diabetes, few studies have explored this in the association between PM and diabetes.

OBJECTIVE

We investigated the role of liver enzymes in mediating the relationship between PM exposure and diabetes.

METHODS

We included a total of 7963 participants from the China Multi-Ethnic Cohort. Residential exposure to PM was assessed using a validated spatial-temporal assessment method. Diabetes was diagnosed according to the criteria from American Diabetes Association. Associations between PM, liver enzyme [including alanine aminotransferase (ALT), aspartate aminotransferase, alkaline phosphatase, and γ-glutamyl transpeptidase (GGT)], and diabetes were estimated using multivariable regression models. The function of liver enzymes in the relationship between PM and diabetes was assessed using mediation analysis.

RESULTS

PM exposure was positively associated with the odds of diabetes, with odds ratios of 1.32 (95% CI 0.83, 2.09), 1.33 (95% CI 1.07, 1.65), and 1.18 (95% CI 1.02, 1.36) for every 10-μg/m3 increment in ≤1 μm (PM1), ≤2.5 μm (PM2.5), and ≤10 μm (PM10) PM, respectively. ALT (4.47%) and GGT (4.78%) exhibited statistically significant mediation effects on the association between PM2.5 and diabetes, and the ALT (4.30%) also had a mediating role on PM10. However, none of the liver enzymes had a significant mediating effect on PM1.

CONCLUSION

The relationship between PM and diabetes is partially mediated by liver enzymes, suggesting that lipid accumulation, oxidative stress, and chronic inflammation in the liver may be involved in its pathogenesis.

Air Quality and Cancer Prevalence Trends across the Sub-Saharan African Regions during 2005-2020

Poor air quality and environmental pollution remain some of the main etiological factors leading to cancers and cancer-related deaths worldwide. As a result of human activities, deleterious airborne chemicals can be dispersed not only in the environment but also released in occupational environments and industrial areas. Air pollutants and cancer links are now established through various oxidative stress-related mechanisms and related DNA damages. Generally, ambient and indoor air pollutants have been understudied in sub-Saharan Africa (SSA) compared to other regions in the world. Our study not only highlights the deleterious effects of air pollutants in these developing countries, but it has strived to examine the trends and correlations between cancers and some air pollutants-carbon dioxide, other greenhouse gases, PM_2.5, and human development index-in some SSA countries, where recent cancer burdens were reported as high. Our results showed strikingly higher yearly trends of cancers and above-mentioned air pollutant levels in some sub-Saharan countries during 2005-2020. Relative risks (RR) of these air pollutants-related cancer case rates were, however, below, or slightly above 1.0, or not statistically significant possibly due to other responsible and confounding factors which were not considered in our analyses due to data unavailability. We recommend new approaches to monitoring, minimizing, and creating awareness of the trends of hazardous air pollutants in sub-Saharan Africa, which will help ameliorate cancer prevalence and support the reduction in air pollution levels within regulatory limits, thereby relieving the cumulative burdens of cancers. Utilization of the findings from the study will support large-scale public health and health policy efforts on cancer management through environmental stewardship in SSA countries having the poorest outcome and the shortest survival rates from cancers.

Laboratory investigation of pollutant emissions and PM2.5 toxicity of underground coal fires

Widespread underground coal fires (UCFs) release large amounts of pollutants, thus leading to air pollution and health impacts. However, this topic has not been widely investigated, especially regarding the potential health hazards. We quantified the pollutant emissions and analyzed the physicochemical properties of UCF PM_2.5 in a laboratory study of coal smoldering under a simulated UCF background. The emission factors of CO₂, CO, and PM_2.5 were 2489 ± 35, 122 ± 9, 12.90 ± 1.79 g/kg, respectively. UCF PM_2.5 are carbonaceous particles with varied morphology and complex composition, including heavy metals, silica and polycyclic aromatic hydrocarbons (PAHs). The main PAHs components were those with 2-4 rings. Benzoapyrene (BaP) and indeno[1,2, 3-cd]pyrene (IcdP) were important contributors to the carcinogenesis of these PAHs. We quantitatively evaluate the toxicity of inhaled UCF PM_2.5 using a nasal inhalation exposure system. The target organs of UCF PM_2.5 are lungs, liver, and kidneys. UCF PM_2.5 presented an enriched chemical composition and induced inflammation and oxidative stress, which together mediated multiple organ injury. Long-term PM_2.5 metabolism is the main cause of persistent toxicity, which might lead to long-term chronic diseases. Therefore, local authorities should recognize the importance and effects of UCF emissions, especially PM_2.5, to establish control and mitigation measures.

Exposure to Air Pollution and Survival in Follow-Up after Hepatocellular Carcinoma

Introduction

Air pollutants are classified as carcinogens by the International Agency for Research on Cancer. Long-term exposure to ambient particulate matter with an aerodiameter of 2.5 μm or lower (PM2.5) has been reported to be linked with increased mortality due to hepatocellular carcinoma (HCC). However, the effects of air pollutants other than PM2.5 on HCC-related mortality have not been fully investigated. Accordingly, we conducted this study to assess the effect of long-term exposure to air pollutants (PM2.5 and nitrogen dioxide [NO2]) on HCC-related mortality.

Method

In 2005, the Taiwan Liver Cancer Network (TLCN) was established by the National Research Program for Genomic Medicine to recruit liver cancer patients from 5 major medical centers in northern, central, and southern Taiwan. The TLCN had successfully recruited 9,344 patients by the end of 2018. In this study, we included 1,000 patients randomly sampled from the TLCN to assess the effect of exposure to air pollutants on HCC mortality after HCC diagnosis. Daily averages of PM2.5 and NO2 concentrations were retrieved from 77 air quality-monitoring stations and interpolated to the townships of patients' residences by using the Kriging method. The effect of air pollutants on HCC survival was assessed using a Cox proportional hazards model.

Results

A total of 940 patients were included in the analysis. After adjusting for potential confounders and mutually adjusting for co-pollutants, we observed that the hazards ratio (95% confidence interval) for HCC-related mortality for every 1-μg/m3 increase in PM2.5 concentration was 1.11 (1.08-1.14) and that for every 1-ppb increase in NO2 concentration was 1.08 (1.03-1.13).

Conclusion

Our study suggests that long-term exposure to PM2.5 and NO2 was associated with decreased survival time in patients with HCC in Taiwan.

Green space exposure during pregnancy and umbilical cord blood levels of liver enzymes

Evidence has suggested better pregnancy outcomes due to exposure to greenspace; however, the studies on such an association with the level of liver enzymes in the cord blood are still nonexistent. Hence, this study investigated the relationship between exposure to greenspace during the entire pregnancy and gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels in cord blood samples. We selected 150 pregnant women from our pregnancy cohort in Sabzevar, Iran (2018). Greenspace exposure was characterized based on (i) residential distance to green space, (ii) time spent in public/private green spaces, (iii) residential surrounding greenspace, (iv) visual access to greenspace, and (v) number of indoor natural pot plants at home. We developed linear regression models to investigate the adjusted associations of greenspace exposure with enzyme levels. Each one interquartile range (IQR) increase in the residential surrounding greenspace (100 m buffer) was related to a reduction of -12.58 (U/L) (95% CI -22.86, -2.29), -3.35 (U/L) (95% CI -5.50, -1.20), and -0.57 (U/L) (95% CI -1.12, -0.02) in the levels of GGT, AST, and ALT, respectively. Moreover, a similar association was observed for the time the participants spent in green spaces. A decrease in the residential distance to large green spaces was related with lower cord blood levels of AST, ALT, and GGT. Having a window with greenspace view at home was significantly related to lower AST level. The results for the indoor plant pots were not conclusive. Our findings suggested an inverse relationship between greenspace exposure during pregnancy and cord blood levels of liver enzymes. Further studies in other settings and populations are needed to confirm our findings.

Adrenal Stress Hormone Regulation of Hepatic Homeostatic Function After an Acute Ozone Exposure in Wistar-Kyoto Male Rats

Ozone-induced lung injury, inflammation, and pulmonary/hypothalamus gene expression changes are diminished in adrenalectomized (AD) rats. Acute ozone exposure induces metabolic alterations concomitant with increases in epinephrine and corticosterone. We hypothesized that adrenal hormones are responsible for observed hepatic ozone effects, and in AD rats, these changes would be diminished. In total, 5-7 days after sham (SH) or AD surgeries, male Wistar-Kyoto rats were exposed to air or 0.8-ppm ozone for 4 h. Serum samples were analyzed for metabolites and liver for transcriptional changes immediately post-exposure. Ozone increased circulating triglycerides, cholesterol, free fatty-acids, and leptin in SH but not AD rats. Ozone-induced inhibition of glucose-mediated insulin release was absent in AD rats. Unlike diminution of ozone-induced hypothalamus and lung mRNA expression changes, AD in air-exposed rats (AD-air/SH-air) caused differential hepatic expression of ∼1000 genes. Likewise, ozone in AD rats caused differential expression of ∼1000 genes (AD-ozone/AD-air). Ozone-induced hepatic changes in SH rats reflected enrichment for pathways involving metabolic processes, including acetyl-CoA biosynthesis, TCA cycle, and sirtuins. Upstream predictor analysis identified similarity to responses produced by glucocorticoids and pathways involving forskolin. These changes were absent in AD rats exposed to ozone. However, ozone caused unique changes in AD liver mRNA reflecting activation of synaptogenesis, neurovascular coupling, neuroinflammation, and insulin signaling with inhibition of senescence pathways. In these rats, upstream predictor analysis identified numerous microRNAs likely involved in glucocorticoid insufficiency. These data demonstrate the critical role of adrenal stress hormones in ozone-induced hepatic homeostasis and necessitate further research elucidating their role in propagating environmentally driven diseases.

Tobacco smoking and solid fuels for cooking and risk of liver cancer: A prospective cohort study of 0.5 million Chinese adults

Previous research found tobacco smoking and solid fuel use for cooking to increase the risk of chronic liver disease mortality, but previous cohort studies have not investigated their independent and joint associations with liver cancer incidence in contemporary China. The China Kadoorie Biobank (CKB) study recruited 0.5 million adults aged 30 to 79 years from 10 areas across China during 2004 to 2008. Participants reported detailed smoking and fuel use information at baseline. After an 11.1-year median follow-up via electronic record linkage, we recorded 2997 liver cancer cases. Overall, 29.4% participants were current smokers. Among those who cooked at least once per month, 48.8% always used solid fuels (ie, coal or wood) for cooking. Tobacco smoking and solid fuel use for cooking were independently associated with increased risks of liver cancer, with hazard ratios (95% confidence intervals [CIs]) of 1.28 (1.15-1.42) and 1.25 (1.03-1.52), respectively. The more cigarettes consumed each day, the earlier the age of starting smoking or the longer duration of solid fuels exposure, the higher the risk (Ptrend  < .001, =.001, =.018, respectively). Compared with never smokers who had always used clean fuels (ie, gas or electricity), ever-smokers who had always used solid fuels for cooking had a 67% (95% CIs: 1.29-2.17) higher risk. Among Chinese adults, tobacco smoking and solid fuel use for cooking were independently associated with higher risk of liver cancer incidence. Stronger association was observed with higher number of daily cigarette consumption, the earlier age of starting smoking and longer duration of solid fuel use.

Long-term exposure to ambient air pollution and serum liver enzymes in older adults: a population-based longitudinal study

PURPOSE

To investigate the association of long-term exposure to ambient air pollution with serum liver enzymes in older adults.

METHODS

In this longitudinal study, we investigated 318,911 adults aged ≥65 years and assessed their long-term residential exposure to particulate matter with an aerodynamic diameter ≤2.5 µm (PM_2.5), particulate matter with an aerodynamic diameter ≤10 µm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃). Linear mixed models and generalized linear mixed models were implemented for exposure-response analyses.

RESULTS

Each interquartile range (IQR) increase of PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ exposures was significantly associated with a 4.6%, 4.6%, 5.6%, 4.6%, 6.2%, and 3.6% increase in alanine aminotransferase (ALT), and a 4.6%, 5.2%, 3.6%, 3.3%, 6.1%, and 4.0% increase in aspartate aminotransferase (AST), respectively. Each IQR increase of PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ exposures was significantly associated with a 23%, 24%, 28%, 17%, 31%, and 19% increase in odds of elevated ALT (>40 U/L), and a 32%, 39%, 40%, 32%, 57%, and 25% increase in odds of elevated AST (>40 U/L), respectively.

CONCLUSIONS

Long-term exposure to ambient air pollution was significantly associated with increased serum liver enzyme levels in older adults, suggesting that air pollution exposures may induce hepatocellular injury.

Short-term effects of ambient air pollution on daily emergency room visits for abdominal pain: a time-series study in Wuhan, China

Short-term exposure to ambient air pollution has been proven to result in respiratory, cardiovascular, and digestive diseases, leading to increased emergency room visits (ERVs). Abdominal pain complaints provide a large proportion of the ERVs, as yet few studies have focused on the correlations between ambient air pollution and abdominal pain, especially in emergency departments within China. Daily data for daily ERVs were collected in Wuhan, China (from January 1, 2016 to December 31, 2018), including air pollution concentration (SO₂, NO₂, PM_2.5, PM₁₀, CO, and O₃), and meteorological variables. We conducted a time-series study to investigate the potential correlation between six ambient air pollutants and ERVs for abdominal pain and their effects, in different genders, ages, and seasons. A total of 16,318 abdominal pain ERVs were identified during the study period. A 10-μg/m³ increase in concentration of SO₂, NO₂, PM_2.5, PM₁₀, CO, and O₃ corresponded respectively to incremental increases in abdominal pain of 4.89% (95% confidence interval [CI]: - 1.50-11.70), 1.85% (95% CI: - 0.29-4.03), 0.83% (95% CI: - 0.05-1.72), - 0.22% (95% CI: - 0.73-0.30), 0.24% (95% CI: 0.08-0.40), and 0.86% (95% CI: 0.04 - 1.69). We observed significant correlations between CO and O₃ and increases in daily abdominal pain ERVs and positive but insignificant correlations between the other pollutants and ERVs (except PM₁₀). The effects were stronger for females (especially SO₂ and O₃: 13.53% vs. - 2.46%; 1.20% vs. 0.47%, respectively) and younger people (especially CO and O_3: 0.25% vs. 0.01%; 1.36% vs. 0.15%, respectively). Males (1.38% vs. 0.87%) and elders (1.27% vs. 0.99%) were more likely to be affected by PM_2.5. The correlations with PM_2.5 were stronger in cool seasons (1.25% vs. - 0.07%) while the correlation with CO was stronger in warm seasons (0.47% vs. 0.14%). Our time-series study suggests that short-term exposure to air pollution (especially CO and O₃) was positively correlated with ERVs for abdominal pain in Wuhan, China, and that the effects varied by season, gender and age. These data can add evidence on how air pollutants affect the human body and may prompt hospitals to take specific precautions on polluted days and maintain order in emergency departments made busier due to the pollution.

Exposure to air pollutants during pregnancy and after birth increases the risk of neonatal hyperbilirubinemia

OBJECTIVES

Exposure to air pollution is associated with increased risks of several adverse conditions in newborns, such as preterm birth. Whether air pollution is associated with neonatal hyperbilirubinemia remains unclear. We aimed to develop and validate an air-quality-based model to better predict neonatal hyperbilirubinemia.

METHODS

A multicenter, population-based cohort of neonates with a gestational age (GA) ≥35 weeks and birth weight ≥2000 g was enrolled in the study. The study was conducted in Shanghai, China, from July 2017 to December 2018. The daily average concentrations of particulate matter (PM) with aerodynamic diameters≤2.5 μm (PM2.5) and ≤10 μm (PM10), sulfur dioxide (SO₂), nitrogen dioxide (NO2) and carbon monoxide (CO) were measured. Neonatal hyperbilirubinemia was diagnosed according to the American Academy of Pediatrics (AAP) guidelines by trained neonatologists. We used logistic least absolute shrinkage and selection operator (LASSO) regression to screen air pollutant indicators related to neonatal hyperbilirubinemia and build an air-quality signature for each patient. An air-quality-based nomogram was then established to predict the risk of neonatal hyperbilirubinemia.

RESULTS

A total of 11196 neonates were evaluated. Prenatal PM10, CO and NO₂ exposure and postpartum SO₂ exposure were significantly associated with neonatal hyperbilirubinemia. The air-quality score was calculated according to the hyperbilirubinemia-related pollutants. The air-quality score of the hyperbilirubinemia group was significantly higher than that of the nonhyperbilirubinemia group (P < .01, odds ratio = 2.97). An air-quality-based logistic regression model was built and showed good discrimination (C-statistic of 0.675 [95% CI (confidence interval), 0.658 to 0.692]) and good calibration. Decision curve analysis showed that the air-quality-based model was better than the traditional clinical model in predicting neonatal hyperbilirubinemia.

CONCLUSIONS

The findings of this study suggest that ambient air pollution exposure is associated with an increased risk of neonatal hyperbilirubinemia. Our results encourage further exploration of this possibility in future studies.