Ethylene oxide and risk of lympho-hematopoietic cancer and breast cancer: a systematic literature review and meta-analysis

Non-genetic factors and breast cancer: an umbrella review of meta-analyses

BACKGROUND

Previous research has found associations between various non-genetic factors and breast cancer (BrCa) risk. This study summarises and appraises the credibility of the available evidence on the association between non-genetic factors and BrCa risk.

METHODS

We conducted an umbrella review of meta-analyses. Medline, Scopus, and the Cochrane databases were systematically searched for meta-analyses examining non-genetic factors and BrCa incidence or mortality. The strength of the evidence was graded in four categories (i.e., weak, suggestive, highly suggestive, convincing).

RESULTS

A total of 781 meta-analyses from 280 publications were evaluated and graded. We included exposures related to anthropometric measurements, biomarkers, breast characteristics and diseases, diet and supplements, environment, exogenous hormones, lifestyle and social factors, medical history, medication, reproductive history, and pregnancy. The largest number of examined associations was found for the category of diet and supplements and for exposures such as aspirin use and active smoking. The statistically significant (P-value < 0.05) meta-analyses were 382 (49%), of which 204 (53.4%) reported factors associated with increased BrCa risk. Most of the statistically significant evidence (n = 224, 58.6%) was graded as weak. Convincing harmful associations with heightened BrCa risk were found for increased body mass index (BMI), BMI and weight gain in postmenopausal women, oral contraceptive use in premenopausal women, increased androstenedione, estradiol, estrone, and testosterone concentrations, high Breast Imaging Reporting and Data System (BIRADS) classification, and increased breast density. Convincing protective factors associated with lower BrCa risk included high fiber intake and high sex hormone binding globulin (SHBG) levels while highly suggestive protective factors included high 25 hydroxy vitamin D [25(OH)D] levels, adherence to healthy lifestyle, and moderate-vigorous physical activity.

CONCLUSIONS

Our findings suggest some highly modifiable factors that protect from BrCa. Interestingly, while diet was the most studied exposure category, the related associations failed to reach higher levels of evidence, indicating the methodological limitations in the field. To improve the validity of these associations, future research should utilise more robust study designs and better exposure assessment techniques. Overall, our study provides knowledge that supports the development of evidence-based BrCa prevention recommendations and guidance, both at an individual level and for public health initiatives.

TRIAL REGISTRATION

PROSPERO CRD42022370675.

[Breast cancer: Could we consider it as an occupational exposure disease?]

OBJECTIVE

Breast cancer is the leading cancer in women in terms of incidence and mortality. The literature currently identifies several risk factors, some modifiable and others not. Because of its multifactorial nature, the combination of factors either increases or reduces the risk of cancer. Since 2004, the first commission's rapport of the French National Environmental Health Plan has recognized the significant impact of occupational exposure on the development of breast cancer. However, neither primary nor secondary preventive measures have yet been implemented in work environment.

METHOD

Based on available literature, we reviewed current knowledge of breast cancer risk factors associated with occupational exposure.

RESULTS

The risk factors identified were ionizing radiation, magnetic fields, certain endocrine disruptors, ethylene oxide and night shift work.

CONCLUSION

Recognition of breast cancer as an occupational disease is complicated. In some cases, however, it may be possible, particularly in cases of multifactorial exposure. This work should help to raise awareness among employers and reinforce preventive measures in the workplace.

Positive association of ethylene oxide levels with young stroke: a population-based study

Background

Ethylene oxide (EtO), a highly reactive organic compound with extensive industrial applications, poses significant health risks. The association between EtO exposure and stroke was not well established. This study examined the association between EtO exposure and stroke among US adults using data from the 2013-2018 National Health and Nutrition Examination Survey (NHANES).

Methods

We used appropriately weighted multifactorial logistic regression models to analyze the data and validated the findings with smoothed curve fitting. Stratified analysis and interaction assessments were performed to evaluate the robustness of the findings.

Results

The study included 5,071 participants, balanced between men and women, with a stroke prevalence of 4.1%. Higher EtO levels were associated with rising rates of stroke (OR = 1.23, 95% CI: 1.06-1.42). Individuals in the top 25% group displayed a stroke prevalence 1.6 times higher than those in the bottom 25% group (OR = 1.60, 95%CI: 1.03-2.48). Stratified analysis demonstrated a significant positive association between EtO and stroke in individuals under 50 years (OR = 1.94, 95%CI: 1.38-2.72), while no significant association was found in those aged 50 and above (OR = 0.97, 95%CI: 0.83-1.14).

Conclusion

This study identified a significant association between EtO exposure and stroke occurrence in young adults in the United States.

Association between ethylene oxide levels and depressive symptoms: A cross-sectional study based on NHANES 2013-2018 database

BACKGROUND AND AIM

Ethylene oxide (EO) is a commonly used compound with known health risks. However, the specific association between EO exposure and the development of depressive symptoms has not been well established. Therefore, this study aimed to examine the potential association between EO exposure, as indicated by hemoglobin adduct of ethylene oxide (HbEO) levels, and the occurrence of depressive symptoms.

METHODS

We employed logistic regression, restricted cubic spline, and subgroup analysis to investigate the association between EO exposure and the occurrence of depressive symptoms. Additionally, we conducted a mediating effect analysis to explore the potential factors influencing the association between EO exposure and depressive symptoms.

RESULTS

Elevated HbEO levels were associated with the development of depressive symptoms. After adjusting for potential confounders, the highest quartile of HbEO levels showed an odds ratio (OR) of 3.37 [95 % confidence interval (CI): 1.87-6.10, P = 0.002] compared with the lowest quartile. Additionally, a linear association was observed between HbEO levels and the risk of depressive symptoms. We also revealed that the levels of several inflammatory factors and triglycerides mediated the association between EO exposure and the occurrence of depressive symptoms.

CONCLUSIONS

Higher levels of EO exposure were related to an increased risk of developing depressive symptoms. The analysis also suggested that the inflammatory response might play a mediating role in the pathway from EO exposure to depressive symptoms.

Associations of ethylene oxide exposure and "Life's Essential 8"

Ethylene oxide (EtO) is a widely used industrial chemical with recognized health risks. While its carcinogenic properties have been extensively studied, emerging evidence suggests potential associations with cardiovascular diseases. Using the recently introduced Life's Essential 8 (LE8) score as a comprehensive cardiovascular health (CVH) measure, this study aimed to elucidate the relationship between EtO exposure and CVH. Data from the National Health and Nutrition Examination Survey (NHANES) encompassing 3748 adults was analyzed. CVH was assessed using the LE8 score, which incorporates diet, physical activity, tobacco/nicotine exposure, sleep duration, BMI, non-HDL cholesterol, blood glucose, and blood pressure. The association between EtO exposure, gauged by Hemoglobin adduct (HbEtO) levels, and CVH was examined using linear regression and Cox regression models. An inverse relationship between EtO exposure and the overall CVH score was identified. Specifically, for every 1-unit increase in ln-transformed HbEtO, a 3.69-point decrease in the total CVH score was observed. An inverted J-shaped association between ln-transformed HbEtO and CVH score emerged, with an inflection point at 3.15 pmol/g Hb. Elevated EtO exposure was not significantly linked to all-cause mortality but was robustly associated with increased cardiovascular mortality. Elevated EtO exposure is negatively associated with CVH, as outlined by the LE8 metrics. Beyond a certain threshold, this association underscores the cardiovascular risks of EtO exposure and highlights the importance of further research to determine underlying mechanisms and recommend preventive strategies.

Association between hemoglobin adducts of ethylene oxide levels and the risk of short sleep duration in the general population: an analysis based on the National Health and Nutrition Examination Survey

This study aimed to evaluate the association between blood ethylene oxide (HbEtO) levels and short sleep duration (SSD). Data of 3438 participants aged 20 years or older in this study were collected from the National Health and Nutrition Examination Survey (NHANES). The ethylene oxide (EtO) biomarker (HbEtO) was quantified in blood using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. SSD was defined as sleep time equal to or less than 6 h. The analyses utilized weighted logistic regression models and restricted cubic spline. There was a significant non-linear relationship between HbEtO levels and the risk of SSD (P for-nonlinearity = 0.035). After the full adjustment for confounders, compared with the lowest quantile, the odds ratios (ORs) with 95% confidence intervals (CIs) of SSD across the quantiles of ethylene oxide levels were 1.54(1.09-2.18), 1.15(0.87-1.53), and 1.80(1.11-2.92), respectively (P for trend < 0.05). In subgroup analysis, people who were female, who were non-Hispanic Black, who never engaged in physical activity, who consumed alcohol ≤ 14 g/day, who were normal weight or obese had a significantly higher risk of SSD when they had highest quartiles of HbEtO levels than those had lowest (p < 0.05). Our study indicated that HbEtO levels, an indicator for EtO exposure, were associated with SSD in general adult populations.

Duration-response association between occupational exposure and pancreatic cancer risk: meta-analysis

BACKGROUND

Evidence is lacking on the occupational exposure time window to chemical agents related to pancreatic cancer risk.

AIMS

This study performed meta-regression and meta-analysis to examine the dose-response association between occupational exposure duration to chemical agents and pancreatic cancer risk.

METHODS

We searched and reviewed studies on exposure duration and pancreatic cancer in five databases (Cochrane Library, EMBASE, PubMed, ScienceDirect and Web of Science) from inception to 16 May 2022. Exposure refers to the years a worker was exposed to any chemical agent, and outcome variables were pancreatic cancer incidence and mortality.

RESULTS

We identified 31 studies, including 288 389 participants. In the meta-regression, the positive dose-response association indicated pancreatic cancer risk increased slightly with every additional year of exposure duration (slope = 1.01; 95% confidence interval [CI] 1.00-1.02). Pancreatic cancer risk increased with an exposure duration of 1-10 (relative risk [RR] = 1.04; 95% CI 1.02-1.06), 11-20 (RR = 1.11; 95% CI 1.05-1.16), and 21-30 years (RR = 1.39; 95% CI 1.12-1.73).

CONCLUSIONS

Pancreatic cancer risk increased as occupational exposure duration increased, with an exposure time window ranging from 1 to 30 years.

Physical activity can influence the relationship between ethylene oxide and risk of kidney stones: A cross-sectional study from the NHANES 2013-2016

Ethylene oxide (EO) is known to cause inflammatory damage, and suitable physical activity can reportedly affect the risk of kidney stones. In this study, we aimed to investigate the relationship between EO and kidney stones and whether physical activity can potentially influence the relationship between EO and kidney stones. Overall, 3,336 adult participants were included; of them, 330 (9.9%) had a self-reported history of kidney stones. Data were obtained from the National Health and Nutrition Examination Survey 2013-2016. Physical activity was calculated using metabolic equivalent, weekly frequency, and duration. Logistic regression and restricted cubic spline (RCS) curves were used to explore the association between physical activity, EO, and kidney stones. Dose-response curves from the RCS showed a nonlinear positive association between EO and kidney stones. Multivariate logistic regression analysis revealed an adjusted odds ratio (aOR) of 1.548 (95% confidence interval 1.123-2.135, P = 0.008) for the risk of kidney stones among participants in the highest quartile (Q4) group compared with those in the lowest quartile (Q1) group. Furthermore, compared to the Q1 group, the aOR for risk of kidney stones in the Q4 group was 1.326 in participants without physical activity, a decreased risk (aOR 1.239) in participants with low physical activity, and an increased risk (aOR 1.981) in those with high physical activity. This study suggests that EO is a risk factor for kidney stones and that suitable physical activity may moderate this relationship to some extent; however, excessive physical activity can exacerbate this relationship.

The association between ethylene oxide exposure and asthma risk: a population-based study

Ethylene oxide (EO) is a reactive epoxide. However, the association between EO exposure and the risk of developing asthma in humans is unknown. The aim of this study was to investigate the relationship between EO exposure and the risk of developing asthma in the general US population. In this cross-sectional study, data of 2542 patients from the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2016 were obtained and analyzed. Hemoglobin adducts of EO (HbEO) level be used as the main factor for predicting EO exposure. The association between the level of EO exposure and the risk of developing asthma was evaluated with logistic regression models and dose-response analysis curves of restricted cubic spline function. Mediation analysis and linear regression analysis were utilized to evaluate the association between EO exposure and inflammation indicators. According to the quartiles of HbEO level, the patients were divided into four groups. The results indicated that an increased HbEO level was associated with a higher risk of asthma onset. Compared with the lowest quartile, the odds ratio (OR) with the 95% confidence interval (CI) for the highest quartile was 1.960 (95% CI: 1.348-2.849, P = 0.003). After being adjusted for numerous potential confounders, the OR of quartile 4 relative to quartile 1 was 1.991 (95% CI: 1.359-2.916, P = 0.001). Consistent results were also obtained in most subgroup analyses and dose-response analysis curves. In addition, EO levels were positively correlated with the inflammatory indicators (P = 0.006 for WBC, P = 0.015 for lymphocyte, and P = 0.015 for neutrophil). This study revealed a positive correlation between the level of EO exposure and the risk of asthma in a representative US population. In addition, inflammatory response may prove to be a potential biological mechanism underlying EO-induced asthma.

Food-Borne Chemical Carcinogens and the Evidence for Human Cancer Risk

Commonly consumed foods and beverages can contain chemicals with reported carcinogenic activity in rodent models. Moreover, exposures to some of these substances have been associated with increased cancer risks in humans. Food-borne carcinogens span a range of chemical classes and can arise from natural or anthropogenic sources, as well as form endogenously. Important considerations include the mechanism(s) of action (MoA), their relevance to human biology, and the level of exposure in diet. The MoAs of carcinogens have been classified as either DNA-reactive (genotoxic), involving covalent reaction with nuclear DNA, or epigenetic, involving molecular and cellular effects other than DNA reactivity. Carcinogens are generally present in food at low levels, resulting in low daily intakes, although there are some exceptions. Carcinogens of the DNA-reactive type produce effects at lower dosages than epigenetic carcinogens. Several food-related DNA-reactive carcinogens, including aflatoxins, aristolochic acid, benzene, benzo[a]pyrene and ethylene oxide, are recognized by the International Agency for Research on Cancer (IARC) as causes of human cancer. Of the epigenetic type, the only carcinogen considered to be associated with increased cancer in humans, although not from low-level food exposure, is dioxin (TCDD). Thus, DNA-reactive carcinogens in food represent a much greater risk than epigenetic carcinogens.

Systematic review of the scientific evidence on ethylene oxide as a human carcinogen

Ethylene oxide is a highly reactive chemical primarily used as an intermediate in chemical production and as a sterilant of medical equipment and food products; it also is produced endogenously as a result of physiological processes. We conducted a systematic review of the potential carcinogenicity of inhaled ethylene oxide in humans using methods that adhere to PRIMSA guidelines and that incorporate aspects from the Institute of Medicine (IOM) (now the National Academy of Medicine) as well as several US Environmental Protection Agency (EPA) frameworks for systematic reviews. After a comprehensive literature search and selection process, study quality was evaluated following a method adapted from the EPA Toxic Substances Control Act (TSCA) framework. The literature screening and selection process identified 24 primary studies in animals or humans and more than 50 mechanistic studies. Integrating epidemiological, animal, and mechanistic literature on ethylene oxide and cancer according to the IOM framework yielded classifications of suggestive evidence of no association between ethylene oxide and stomach cancer, breast cancer and lymphohematopoietic malignancies at human relevant exposures. However, we acknowledge that there is additional uncertainty in the classification for lymphohematopoietic malignancies owing to a paucity of evidence for specific types of these tumors, each of which is a distinct disease entity of possibly unique etiology.

Association between blood ethylene oxide levels and the risk of cardiovascular diseases in the general population

Ethylene oxide (EtO) is a highly reactive organic compound that is mainly used as a sterilizing agent. However, to date, the effects of EtO on the cardiovascular system are not clear. We aimed to explore the association between blood EtO levels and the risk of cardiovascular disease (CVD) in the general US population. We obtained information on blood levels of EtO and CVD outcomes in 3,410 participants from the National Health and Nutritional Examination Survey (NHANES) 2013-2014 and 2015-2016. Logistic regression models were applied to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association between EtO and risk of all CVD as well as subtypes of CVD. Linear regression analyses were used to estimate the associations of EtO with potential mechanistic parameters of CVD, including blood pressure, blood lipid levels and inflammatory parameters. Higher blood levels of EtO were associated with an increased risk of all CVD (p for trend = 0.003), with an adjusted OR (95% CI) in the highest quartile of 1.94 (1.24, 3.02) compared with the lowest quartile as a reference. Higher concentrations of EtO were positively associated with the risk of angina (p for trend = 0.04) and heart attack (p for trend = 0.011). In addition, the concentration of EtO was positively associated with the levels of triglycerides, white blood cells, lymphocytes, monocytes, neutrophils and eosinophils (p = 0.003 for eosinophils and p < 0.001 for the others) and negatively associated with the level of high-density lipoprotein cholesterol (p < 0.001). We found that exposure to EtO was associated with angina, heart attack and all CVD in a large representative US population. Furthermore, EtO may induce CVD through the inflammatory response and abnormal fatty acid metabolism.

Association of exposure to ethylene oxide with risk of diabetes mellitus: results from NHANES 2013-2016

Animal studies suggested that exposure to ethylene oxide (EO) might induce hepatic lipid peroxidation and inflammatory lesions in various organs. However, the association between EO exposure and diabetes risk in humans is unknown. This study aimed to examine the association of EO exposure with the prevalence of diabetes mellitus in a general population of US adults. This study consisted of 3448 participants aged 20 years and older from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 cycle and 2015-2016 cycle. Circulating levels of EO biomarker (hemoglobin adducts of EO (HbEO)) was measured by using high-performance liquid chromatography coupled with tandem mass spectrometry. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariate logistic regression. The weighted median level of HbEO was 29.9 (95% CI: 21.8, 56.0) pmol/g Hb. Elevated levels of HbEO were associated with higher HbA1c and lower high-density lipoprotein cholesterol (both P_trend <0.01). After multivariate adjustment including demographics, lifestyle factors, and body mass index (BMI), higher HbEO levels were significantly associated with an increased prevalence of diabetes mellitus. The OR (95% CI) of diabetes across increasing quartiles of HbEO was 1.00 (reference), 1.45 (1.08, 1.96), 1.76 (1.31, 2.36), and 1.77 (1.22, 2.57), respectively (P_trend <0.001). Similar results were observed when analyses were stratified by smoking status, age, sex, race/ethnicity, and BMI. In a nationally representative sample of US adults, higher levels of HbEO were significantly associated with an increased prevalence of diabetes mellitus. Further prospective studies are needed to confirm these findings.

Reversible cerebral vasoconstriction syndrome with cerebral infarction caused by acute high-level vapor exposure of ethylene oxide: a case report

Background

With the increasing production and use of ethylene oxide (EO) worldwide, its explicit bio-toxicity has drawn more and more attention. At present, most studies focus on chronic EO exposure. Studies on acute EO exposure are rare, especially with imaging studies. To our knowledge, this work is the first documented case of reversible cerebral vasoconstriction syndrome (RCVS) with cerebral infarction caused by EO.

Case presentation

A 58-year-old woman who worked in a capsule production factory got an unprotected acute EO inhalation due to accidental exposure to sterilization gas. She suffered from nausea, vomiting, and severe paroxysmal headaches, but the first brain MRI scan of the patient showed no significant abnormality. Nine days after inhalation, she developed recurrent thunderclap headaches and gradual complete blindness. The follow-up brain MRI, 12 days after inhalation, demonstrated extensive cytotoxic edema. Fifteen days and 21 days after EO (ethylene oxide) inhalation, head MRA and CTA respectively showed diffuse vasoconstriction of cerebral arteries. Fifty-nine days after EO inhalation, head MRA assessed reversibility of the vasoconstriction. According to clinical features and imaging findings, RCVS with cerebral infarction can be diagnosed. The patient was sensitive to light and light reflection but still blind after symptomatic and rehabilitation therapy.

Conclusions

We report an acute EO exposure case in which the patient suffered from RCVS with cerebral infarction, which previous literature has not reported. This article aimed to raise awareness of encephalopathy after EO acute exposure.

Breast cancer and occupational exposures: an integrative review of the literature

Occupational factors can lead to breast cancer, though the relationship between these variables is not well established. The objective of this study was to search the relevant literature for information on the association between breast cancer and exposure to occupational risk factors. For that purpose, electronic databases were searched using the following keywords: breast cancer and occupational exposures. A total of 40 articles published in the 10-year period from 2009 to 2019 were included in this review. Workers exposed to metals such as cadmium, chemical products, radiation and night work were more susceptible to breast cancer. The findings showed significant evidence to support an association between breast cancer and some chemical products, ionizing radiation and night work. However, most studies have difficulty establishing a causal relationship between these variables, pointing to the need for further investigation of these issues.

Ethylene oxide review: characterization of total exposure via endogenous and exogenous pathways and their implications to risk assessment and risk management

This review is intended to provide risk assessors and risk managers with a better understanding of issues associated with total exposures of human populations to ethylene oxide from endogenous and exogenous pathways. Biomonitoring of human populations and lab animals exposed to ethylene oxide has relied upon the detection of hemoglobin adducts such as 2-hydroxyethylvaline (HEV), which provides a useful measure of total exposure to ethylene oxide from all pathways. Recent biomonitoring data from CDC provide an excellent characterization of total exposure to ethylene oxide to the general U.S. population by demographic factors such as age, gender, and race as well as smoking habit, which might be comparable to previous measurements reported for humans and lab animals. The biochemical pathways including gastrointestinal (production by bacteria) and systemic (enzymatic production) pathways by which endogenous ethylene is generated and converted to ethylene oxide are described. The relative importance of endogenous pathways and exogenous pathways via ambient air or tobacco smoke was quantified based upon available data to characterize their relative importance to total exposure. Considerable variation was noted for HEV measurements in human populations, and important sources of variation for all pathways are discussed. Issues related to risk assessment and risk management of human populations exposed to ethylene oxide are provided within the context of characterizing total exposure, and data needs for supporting future risk assessment identified.

Associations between observed concentrations of ethylene oxide in whole blood and smoking, exposure to environmental tobacco smoke, and cancers including breast cancer: data for US children, adolescents, and adults

For the first time, National Health and Nutrition Examination Survey released data on ethylene oxide (ETO) into public domain for US children aged 6-11 years, adolescents aged 12-19 years, and adults aged ≥ 20 years for 2013-2016. This study was undertaken to evaluate the associations between concentrations of ETO in whole blood and smoking, exposure to environmental tobacco smoke (ETS), and self-reported diagnosis of cancers including breast cancer. Both adolescent (29.6 vs. 49.6 pmol/g Hb, p < 0.01) and adult smokers (31.5 vs. 142.7 pmol/g Hb, p < 0.01) were found to have substantially higher adjusted levels of ethylene oxide than nonsmokers. Non-Hispanic blacks had higher levels of ethylene oxide than other race/ethnicities for children and adolescents. Non-Hispanic Asians had higher levels of ethylene oxide than other race/ethnicities for adults. Exposure to ETO measured by the number of smokers smoking inside the home (p < 0.01) and number of days smokers smoked inside the home (p = 0.03) during the prior week was found to be associated with elevated levels of ETO (p < 0.01) among US adults. Increased age was associated with elevated levels of ETO among adolescents (p = 0.02) and adults (p < 0.01) but the reverse was true for children (p = 0.04). For the general US population, levels of ETO were not found to be associated with cancers including breast cancer.