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EBioMedicine May 2024This study investigates the associations between air pollution and colorectal cancer (CRC) risk and survival from an epigenomic perspective. (Meta-Analysis)
Meta-Analysis
BACKGROUND
This study investigates the associations between air pollution and colorectal cancer (CRC) risk and survival from an epigenomic perspective.
METHODS
Using a newly developed Air Pollutants Exposure Score (APES), we utilized a prospective cohort study (UK Biobank) to investigate the associations of individual and combined air pollution exposures with CRC incidence and survival, followed by an up-to-date systematic review with meta-analysis to verify the associations. In epigenetic two-sample Mendelian randomization analyses, we examine the associations between genetically predicted DNA methylation related to air pollution and CRC risk. Further genetic colocalization and gene-environment interaction analyses provided different insights to disentangle pathogenic effects of air pollution via epigenetic modification.
FINDINGS
During a median 12.97-year follow-up, 5767 incident CRC cases among 428,632 participants free of baseline CRC and 533 deaths in 2401 patients with CRC were documented in the UK Biobank. A higher APES score was associated with an increased CRC risk (HR, 1.03, 95% CI = 1.01-1.06; P = 0.016) and poorer survival (HR, 1.13, 95% CI = 1.03-1.23; P = 0.010), particularly among participants with insufficient physical activity and ever smokers (P > 0.05). A subsequent meta-analysis of seven observational studies, including UK Biobank data, corroborated the association between PM exposure (per 10 μg/m increment) and elevated CRC risk (RR,1.42, 95% CI = 1.12-1.79; P = 0.004; I = 90.8%). Genetically predicted methylation at PM-related CpG site cg13835894 near TMBIM1/PNKD and cg16235962 near CXCR5, and NO-related cg16947394 near TMEM110 were associated with an increased CRC risk. Gene-environment interaction analysis confirmed the epigenetic modification of aforementioned CpG sites with CRC risk and survival.
INTERPRETATION
Our study suggests the association between air pollution and CRC incidence and survival, underscoring the possible modifying roles of epigenomic factors. Methylation may partly mediate pathogenic effects of air pollution on CRC, with annotation to epigenetic alterations in protein-coding genes TMBIM1/PNKD, CXCR5 and TMEM110.
FUNDING
Xue Li is supported by the Natural Science Fund for Distinguished Young Scholars of Zhejiang Province (LR22H260001), the National Nature Science Foundation of China (No. 82204019) and Healthy Zhejiang One Million People Cohort (K-20230085). ET is supported by a Cancer Research UK Career Development Fellowship (C31250/A22804). MGD is supported by the MRC Human Genetics Unit Centre Grant (U127527198).
Topics: Aged; Female; Humans; Male; Middle Aged; Air Pollutants; Air Pollution; Colorectal Neoplasms; DNA Methylation; Environmental Exposure; Epigenesis, Genetic; Epigenomics; Gene-Environment Interaction; Incidence; Mendelian Randomization Analysis; Prospective Studies; Risk Factors
PubMed: 38631091
DOI: 10.1016/j.ebiom.2024.105126 -
Headache Oct 2023To systematically synthesize evidence from a broad range of studies on the association between air pollution and migraine. (Review)
Review
OBJECTIVE
To systematically synthesize evidence from a broad range of studies on the association between air pollution and migraine.
BACKGROUND
Air pollution is a ubiquitous exposure that may trigger migraine attacks. There has been no systematic review of this possible association.
METHODS
We searched for empirical studies assessing outdoor air pollution and any quantified migraine outcomes. We included short- and long-term studies with quantified air pollution exposures. We excluded studies of indoor air pollution, perfume, or tobacco smoke. We assessed the risk of bias with the World Health Organization's bias assessment instrument for air quality guidelines.
RESULTS
The final review included 12 studies with over 4,000,000 participants. Designs included case-crossover, case-control, time series, and non-randomized pre-post intervention. Outcomes included migraine-related diagnoses, diary records, medical visits, and prescriptions. Rather than pooling the wide variety of exposures and outcomes into a meta-analysis, we tabulated the results. Point estimates above 1.00 reflected associations of increased risk. In single-pollutant models, the percent of point estimates above 1.00 were carbon monoxide 5/5 (100%), nitrogen dioxide 10/13 (78%), ozone 7/8 (88%), PM 13/15 (87%), PM 2/2 (100%), black carbon 0/1 (0%), methane 4/6 (75%), sulfur dioxide 3/5 (60%), industrial toxic waste 1/1 (100%), and proximity to oil and gas wells 6/13 (46%). In two-pollutant models, 16/17 (94%) of associations with nitrogen dioxide were above 1.00; however, more than 75% of the confidence intervals included the null value. Most studies had low to moderate risks of bias. Where differences were observed, stronger quality articles generally reported weaker associations.
CONCLUSIONS
Balancing the generally strong methodologies with the small number of studies, point estimates were mainly above 1.00 for associations of carbon monoxide, nitrogen dioxide, ozone, and particulate matter with migraine. These results were most consistent for nitrogen dioxide.
Topics: Humans; Air Pollutants; Air Pollution; Environmental Exposure; Environmental Pollutants; Nitrogen Dioxide; Ozone
PubMed: 37795754
DOI: 10.1111/head.14632 -
Human Reproduction Update Jan 2023Air pollution is both a sensory blight and a threat to human health. Inhaled environmental pollutants can be naturally occurring or human-made, and include...
BACKGROUND
Air pollution is both a sensory blight and a threat to human health. Inhaled environmental pollutants can be naturally occurring or human-made, and include traffic-related air pollution (TRAP), ozone, particulate matter (PM) and volatile organic compounds, among other substances, including those from secondhand smoking. Studies of air pollution on reproductive and endocrine systems have reported associations of TRAP, secondhand smoke (SHS), organic solvents and biomass fueled-cooking with adverse birth outcomes. While some evidence suggests that air pollution contributes to infertility, the extant literature is mixed, and varying effects of pollutants have been reported.
OBJECTIVE AND RATIONALE
Although some reviews have studied the association between common outdoor air pollutants and time to pregnancy (TTP), there are no comprehensive reviews that also include exposure to indoor inhaled pollutants, such as airborne occupational toxicants and SHS. The current systematic review summarizes the strength of evidence for associations of outdoor air pollution, SHS and indoor inhaled air pollution with couple fecundability and identifies gaps and limitations in the literature to inform policy decisions and future research.
SEARCH METHODS
We performed an electronic search of six databases for original research articles in English published since 1990 on TTP or fecundability and a number of chemicals in the context of air pollution, inhalation and aerosolization. Standardized forms for screening, data extraction and study quality were developed using DistillerSR software and completed in duplicate. We used the Newcastle-Ottawa Scale to assess risk of bias and devised additional quality metrics based on specific methodological features of both air pollution and fecundability studies.
OUTCOMES
The search returned 5200 articles, 4994 of which were excluded at the level of title and abstract screening. After full-text screening, 35 papers remained for data extraction and synthesis. An additional 3 papers were identified independently that fit criteria, and 5 papers involving multiple routes of exposure were removed, yielding 33 articles from 28 studies for analysis. There were 8 papers that examined outdoor air quality, while 6 papers examined SHS exposure and 19 papers examined indoor air quality. The results indicated an association between outdoor air pollution and reduced fecundability, including TRAP and specifically nitrogen oxides and PM with a diameter of ≤2.5 µm, as well as exposure to SHS and formaldehyde. However, exposure windows differed greatly between studies as did the method of exposure assessment. There was little evidence that exposure to volatile solvents is associated with reduced fecundability.
WIDER IMPLICATIONS
The evidence suggests that exposure to outdoor air pollutants, SHS and some occupational inhaled pollutants may reduce fecundability. Future studies of SHS should use indoor air monitors and biomarkers to improve exposure assessment. Air monitors that capture real-time exposure can provide valuable insight about the role of indoor air pollution and are helpful in assessing the short-term acute effects of pollutants on TTP.
Topics: Pregnancy; Female; Humans; Air Pollution; Air Pollutants; Tobacco Smoke Pollution; Particulate Matter; Fertility; Environmental Pollutants
PubMed: 35894871
DOI: 10.1093/humupd/dmac029 -
The Science of the Total Environment Feb 2023This systematic review summarises and evaluates the literature investigating associations between exposure to air pollution and general population cognition, which has... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
This systematic review summarises and evaluates the literature investigating associations between exposure to air pollution and general population cognition, which has important implications for health, social and economic inequalities, and human productivity.
METHODS
The engines MEDLINE, Embase Classic+Embase, APA PsycInfo, and SCOPUS were searched up to May 2022. Our inclusion criteria focus on the following pollutants: particulate matter, NOx, and ozone. The cognitive abilities of interest are: general/global cognition, executive function, attention, working memory, learning, memory, intelligence and IQ, reasoning, reaction times, and processing speed. The collective evidence was assessed using the NTP-OHAT framework and random-effects meta-analyses.
RESULTS
Eighty-six studies were identified, the results of which were generally supportive of associations between exposures and worsened cognition, but the literature was varied and sometimes contradictory. There was moderate certainty support for detrimental associations between PM and general cognition in adults 40+, and PM, NOx, and PM and executive function (especially working memory) in children. There was moderate certainty evidence against associations between ozone and general cognition in adults age 40+, and NOx and reasoning/IQ in children. Some associations were also supported by meta-analysis (N = 14 studies, all in adults aged 40+). A 1 μg/m increase in NO was associated with reduced performance on general cognitive batteries (β = -0.02, p < 0.05) as was a 1 μg/m increase in PM exposure (β = -0.02, p < 0.05). A 1μgm increase in PM was significantly associated with lower verbal fluency by -0.05 words (p = 0.01) and a decrease in executive function task performance of -0.02 points (p < 0.001).
DISCUSSION
Evidence was found in support of some exposure-outcome associations, however more good quality research is required, particularly with older teenagers and young adults (14-40 years), using multi-exposure modelling, incorporating mechanistic investigation, and in South America, Africa, South Asia and Australasia.
Topics: Child; Adolescent; Young Adult; Humans; Air Pollutants; Environmental Exposure; Air Pollution; Particulate Matter; Ozone; Cognition
PubMed: 36427724
DOI: 10.1016/j.scitotenv.2022.160234 -
Ecotoxicology and Environmental Safety Apr 2023We aimed to evaluate the relationship between the composition of particulate matter (PM) and gestational diabetes mellitus (GDM) by a comprehensively review of... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
We aimed to evaluate the relationship between the composition of particulate matter (PM) and gestational diabetes mellitus (GDM) by a comprehensively review of epidemiological studies.
METHODS
We systematically identified cohort studies related to air pollution and GDM risk before February 8, 2023 from six databases (PubMed, Embase, Web of Science Core Collection, China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform and Chongqing VIP Chinese Science and Technology Periodical databases). We calculated the relative risk (RR) and its 95% confidence intervals (CIs) to assess the overall effect by using a random effects model.
RESULTS
This meta-analysis of 31 eligible cohort studies showed that exposure to PM, PM, SO, and NO was associated with a significantly increased risk of GDM, especially in preconception and first trimester. Analysis of the components of PM found that the risk of GDM was strongly linked to black carbon (BC) and nitrates (NO). Specifically, BC exposure in the second trimester and NO exposure in the first trimester elevated the risk of GDM, with the RR of 1.128 (1.032-1.231) and 1.128 (1.032-1.231), respectively. The stratified analysis showed stronger correlations of GDM risk with higher levels of pollutants in Asia, except for PM and BC, which suggested that the specific composition of particulate pollutants had a greater effect on the exposure-outcome association than the concentration.
CONCLUSIONS
Our study found that ambient air pollutant is a critical factor for GDM and further studies on specific particulate matter components should be considered in the future.
Topics: Pregnancy; Female; Humans; Diabetes, Gestational; Air Pollution; Air Pollutants; Particulate Matter; Cohort Studies; Environmental Exposure
PubMed: 36934545
DOI: 10.1016/j.ecoenv.2023.114802 -
The Science of the Total Environment Dec 2023Growing studies have focused on the effects of ambient air pollution on thyroid hormones (THs), but the results were controversial. Therefore, a systematic review and... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Growing studies have focused on the effects of ambient air pollution on thyroid hormones (THs), but the results were controversial. Therefore, a systematic review and meta-analysis was conducted by pooling current evidence on this association.
METHODS
Four databases were searched for studies examining the associations of particulate matter [diameter ≤10 μm (PM) or ≤2.5 μm (PM)] and gaseous [sulfur dioxide (SO), nitrogen dioxide (NO), ozone (O), carbon monoxide (CO)] pollutants with THs levels. Random effects models were used to pool the changes in THs levels with increasing air pollutant concentrations. Subgroup analyses were constructed by region, design, sample size, pollutant concentrations, evaluated methods, and potential risk exposure windows.
RESULTS
A total of 14 studies covering 357,226 participants were included in this meta-analysis. The pooled results showed significant associations of exposure to PM, PM, NO, SO, and CO with decreases in free thyroxine (FT4) with percent changes (PC) ranging from -0.593 % to -3.925 %. PM, NO, and CO were negatively associated with levels of FT4/FT3 (PC: from -0.604 % to -2.975 %). In addition, results showed significant associations of PM with hypothyroxinemia and high thyroid-stimulating hormone (TSH). Subgroup analyses indicated that PM and NO were significantly associated with FT4 in studies of Chinese, and similar significant findings were found in studies of PM and FT4/FT3 in areas with higher concentrations of air pollutants and larger samples. PM exposure in the first trimester was found to be associated with lower FT4 levels in pregnant women.
CONCLUSION
Our findings suggest that exposure to air pollution is associated with changes in THs levels. Enhanced management of highly polluted areas, identification of harmful components and sources of PM, and protection from harmful exposures in early pregnancy may be of great public health importance for the population's thyroid function.
Topics: Female; Humans; Pregnancy; Nitrogen Dioxide; Thyroid Gland; Environmental Exposure; Air Pollution; Air Pollutants; Particulate Matter; Ozone; Sulfur Dioxide; Thyroid Hormones; Environmental Pollutants
PubMed: 37660827
DOI: 10.1016/j.scitotenv.2023.166780 -
Acta Neurochirurgica Sep 2022Concerns arise when patients with pneumocephalus engage in air travel. How hypobaric cabin pressure affects intracranial air is largely unclear. A widespread concern is... (Review)
Review
INTRODUCTION
Concerns arise when patients with pneumocephalus engage in air travel. How hypobaric cabin pressure affects intracranial air is largely unclear. A widespread concern is that the intracranial volume could relevantly expand during flight and lead to elevated intracranial pressure. The aim of this systematic review was to identify and summarise models and case reports with confirmed pre-flight pneumocephalus.
METHODS
The terms (pneumocephalus OR intracranial air) AND (flying OR fly OR travel OR air transport OR aircraft) were used to search the database PubMed on 30 November 2021. This search returned 144 results. To be included, a paper needed to fulfil each of the following criteria: (i) peer-reviewed publication of case reports, surveys, simulations or laboratory experiments that focussed on air travel with pre-existing pneumocephalus; (ii) available in full text.
RESULTS
Thirteen studies met the inclusion criteria after title or abstract screening. We additionally identified five more articles when reviewing the references. A notion that repeatedly surfaced is that any air contained within the neurocranium increases in volume at higher altitude, much like any extracranial gas, potentially resulting in tension pneumocephalus or increased intracranial pressure.
DISCUSSION
Relatively conservative thresholds for patients flying with pneumocephalus are suggested based on models where the intracranial air equilibrates with cabin pressure, although intracranial air in a confined space would be surrounded by the intracranial pressure. There is a discrepancy between the models and case presentations in that we found no reports of permanent or transient decompensation secondary to a pre-existing pneumocephalus during air travel. Nevertheless, the quality of examination varies and clinicians might tend to refrain from reporting adverse events. We identified a persistent extracranial to intracranial fistulous process in multiple cases with newly diagnosed pneumocephalus after flight. Finally, we summarised management principles to avoid complications from pneumocephalus during air travel and argue that a patient-specific understanding of the pathophysiology and time course of the pneumocephalus are potentially more important than its volume.
Topics: Air Travel; Humans; Intracranial Hypertension; Intracranial Pressure; Pneumocephalus
PubMed: 35794427
DOI: 10.1007/s00701-022-05297-5 -
Annual Review of Medicine Jan 2024We review current knowledge on the trends and drivers of global wildfire activity, advances in the measurement of wildfire smoke exposure, and evidence on the health... (Meta-Analysis)
Meta-Analysis
We review current knowledge on the trends and drivers of global wildfire activity, advances in the measurement of wildfire smoke exposure, and evidence on the health effects of this exposure. We describe methodological issues in estimating the causal effects of wildfire smoke exposures on health and quantify their importance, emphasizing the role of nonlinear and lagged effects. We conduct a systematic review and meta-analysis of the health effects of wildfire smoke exposure, finding positive impacts on all-cause mortality and respiratory hospitalizations but less consistent evidence on cardiovascular morbidity. We conclude by highlighting priority areas for future research, including leveraging recently developed spatially and temporally resolved wildfire-specific ambient air pollution data to improve estimates of the health effects of wildfire smoke exposure.
Topics: Humans; Air Pollution; Environmental Exposure; Hospitalization; Smoke; Wildfires
PubMed: 37738508
DOI: 10.1146/annurev-med-052422-020909 -
Laryngoscope Investigative... Apr 2022Chronic rhinosinusitis (CRS) is a highly prevalent and burdensome disease. The pathophysiology is not fully elucidated, but environmental pollutants have been suggested... (Review)
Review
OBJECTIVE
Chronic rhinosinusitis (CRS) is a highly prevalent and burdensome disease. The pathophysiology is not fully elucidated, but environmental pollutants have been suggested to impact the inflammatory component of the disease process. This review aims to summarize the role of environmental pollution in CRS onset and disease severity.
METHODS
A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases were queried in August 2021. Original articles reporting on air pollution exposure in CRS were included. Other forms of sinonasal disease were excluded.
RESULTS
Literature search produced 11,983 articles, of which 10 met inclusion criteria. Outcomes evaluated included incidence/prevalence, disease severity, quality of life, and histopathologic/microbial changes. Air pollutant exposure was associated with higher odds of CRS, particularly with particulate matter (PM) exposure. Increasing air pollution exposure was also associated with worsened disease severity and detectable histopathologic changes. Impact on quality of life was less clear.
CONCLUSION
Air pollution (particularly PM) is correlated with CRS incidence/prevalence and disease severity, with evidence of histopathologic changes in CRS tissue samples. Further research is warranted to better understand the mechanisms by which air pollution components may cause CRS and type 2 inflammation.
LEVEL OF EVIDENCE
3a.
PubMed: 35434330
DOI: 10.1002/lio2.774 -
Journal of Environmental Sciences... Apr 2023Air pollution has previously been linked to several adverse health outcomes, but the potential association between air pollution and liver cancer remains unclear. We... (Review)
Review
Air pollution has previously been linked to several adverse health outcomes, but the potential association between air pollution and liver cancer remains unclear. We searched PubMed, EMBASE, and Web of Science from inception to 10 October 2021, and manually reviewed the references of relevant papers to further identify any related literature investigating possible associations between air pollution and liver cancer. Risk estimates values were represented by statistical associations based on quantitative analyses. A total of 13 cohort studies obtained from 11 articles were included, with 10,961,717 participants. PM was the most frequently examined pollutant (included in 11 studies), followed by NO and NO (included in 6 studies), and fewer studies focused on other pollutants (PM, PM, PM, O, and BC). In all the 16 associations for liver cancer mortality, 14 associations reported the effect of PM on liver cancer mortality. Eight associations on PM were significant, showing a suggestive association between PM and liver cancer mortality. Among 24 associations shown by risk estimates for liver cancer incidence, most associations were not statistically significant. For other air pollutants, no positive associations were presented in these studies. PM was the most frequently examined pollutant, followed by NO and NO, and fewer studies focused on other pollutants. PM was associated with liver cancer mortality, but there was no association for other air pollutants. Future research should use advanced statistical methods to further assess the impact of multiple air pollutants on liver cancer in the changing socio-environmental context.
Topics: Humans; Air Pollution; Air Pollutants; Liver Neoplasms; Environmental Pollutants
PubMed: 36503807
DOI: 10.1016/j.jes.2022.05.037