Serum concentrations of persistent organic pollutants and colorectal cancer risk: A case-cohort study within Korean National Cancer Center Community (KNCCC) cohort

Epidemiology of colorectal cancer: A review with special emphasis on India

Colorectal cancer (CRC) is a common malignancy and cause for death around the world. In India, it ranks as the fourth most incident cancer in both sexes, with 64,863 cases and 38,367 deaths in 2022. With such high mortality, CRC survival in India is way lesser than that of developed countries. While western countries are facing an overall decline in CRC incidence, various regions in India are seeing an increasing trend. Within India, urban regions have markedly higher incidence than rural. Risk factors include consumption of red and processed meat, fried and sugary food, smoking and alcohol, comorbidities such as obesity, diabetes and inflammatory bowel disease (IBD), family history of CRC, adenomas and genetic syndromes, radiation exposure, pesticides and asbestos. Consumption of nutrient-rich well-balanced diets abundant in vegetables, dairy products, whole grains, nuts and legumes combined with physical activity are protective against CRC. Besides these, metformin, aspirin and micronutrient supplements were inversely associated with the development of CRC. Since a considerable proportion of CRC burden is attributed to modifiable risk factors, execution of population level preventive strategies is essential to limit the growing burden of CRC. Identifying the necessity, in this review, we explore opportunities for primary prevention and for identifying high-risk populations of CRC to control its burden in the near future.

Environmental and occupational exposure to organochlorine pesticides associated with Parkinson's disease risk: A systematic review and meta-analysis based on epidemiological evidence

OBJECTIVES

The purpose of this study was to analyze the association between environmental and occupational organochlorine pesticides (OCPs) exposure and Parkinson's disease (PD) risk.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A comprehensive search of articles before March 18, 2024, was conducted through PubMed, Cochrane, Embase, Medlin and Web of Science databases, and the relevant data were expressed as odds ratios (OR) and 95 % confidence intervals (CI). Newcastle-Ottawa Scale (NOS) was used to evaluate literature quality. STATA (Version 11.0) was used for analysis.

RESULTS

This meta-analysis included 17 case-control studies. The results showed that OCPs exposure increased PD risk, including seven blood sample assessment exposure (BOCPs) studies (OR = 1.54, 95 % CI = 1.32-1.79) and 10 indirect assessment exposure (IOCPs) studies (OR = 1.19, 95 % CI = 1.04-1.35). Location subgroup analysis showed that OCPs was positively associated with PD risk in Asia, while there was no statistical significance in North America and Europe. The IOCPs functional subclasses subgroup results suggested that organochlorine insecticides were significantly associated with PD risk (OR = 1.18, 95%CI = 1.03-1.37). Study time may be a factor of high heterogeneity in BOCPs. In addition, BOCPs (OR = 1.49, 95%CI = 1.28-1.74) and IOCPs (OR = 1.10, 95%CI = 0.95-1.26) showed different results with PD risk.

CONCLUSIONS

Study suggests that OCPs exposure may be a risk factor for PD, but there may be location and OCPs type differences.

Associations between polychlorinated biphenyls and cancer risk among type 2 diabetes: The modifying effects of lifestyle

A growing percentage of diabetes-related deaths has been attributed to cancer, with environmental factors playing important contributions. Thus, we studied the potential relationship between endocrine disruptors polychlorinated biphenyls (PCBs) and cancer risk in diabetes. We aimed to evaluate the association between serum seven indicator-PCB (PCB-28/52/101/118/138/153/180) levels and incident cancer, and further explore the possible modifying role of lifestyle. A total of 2806 type 2 diabetes mellitus (T2DM) cases were included from the Dongfeng-Tongji cohort at the baseline in 2008 and tracked until December 2018, and 320 incident cancers were identified during about 10-year follow-up. Cox proportional hazards models and competing risk regression models were used to reveal associations of baseline concentrations of PCBs with total cancer and specific cancer, respectively. Lifestyle score was determined by body mass index, waist circumference, physical activity, smoking, alcohol drinking, and diet. Each interquartile range (IQR) increment of non-dioxin-like PCBs (NDL-PCBs) generated an 8%-30% increase in cancer incidence. Individuals in the highest quartile for PCB-52, PCB-101, PCB-138, and lowly chlorinated PCBs had 1.44- to 1.68-fold higher cancer risk compared to those in the lowest quartile. Restricted cubic spline analyses and the quantile g-computation model showed similar results. Significant interactions were found between PCBs and fasting blood glucose or simplified insulin resistance assessment indicators. NDL-PCBs were positively and significantly associated with gastrointestinal cancer and respiratory cancer, especially with liver cancer, colorectal cancer, and lung cancer. Higher PCBs showed a significant increase in total cancer risk among participants with an unhealthy lifestyle, however, no associations were observed in those with a relatively healthy lifestyle (Pinteraction < 0.05). Our findings indicated an increased cancer risk associated with NDL-PCBs, highlighted the role of a healthy lifestyle in potentially reducing adverse impact, and provided preliminary data for environmental and public health interventions to alleviate the risk of cancer among diabetes.

Organic food and internal exposure to pollutants among Flemish adolescents

Contrary to the initial hypothesis, Flemish adolescents who reported consuming organic food at least 7.5 times per week did not exhibit reduced internal exposure to the tested recently used pesticides. After adjustment for gender, age, country of origin, socioeconomic status, body mass index, consumption of high-fat foods and foods linked to organic food consumption, and concerning organochlorine derivatives and lead, additional adjustment for the duration of breastfeeding expressed in weeks, they displayed slightly elevated internal exposure to organochlorine derivatives, lead, methyl arsenate, and toxic relevant arsenic. A comparison was also made between the correlation of internal exposure to pollutants with the frequency of organic food consumption on one hand and the total consumption of equivalent products from all sources on the other. Regarding potatoes, vegetables, and fruits, no clear trends were observed. Regarding eggs, there was a trend towards higher internal exposures with organic food consumption, significant for trans-nonachlor, PCB118, and 2,4-dichlorophenoxyacetic acid, and marginally significant for glyphosate. For dairy, there was a trend towards higher internal exposures with organic food consumption, significant for perfluorononanoic acid and marginally significant for PCB153. Regarding nuts and seeds, the higher internal exposure to dichlorophenoxyacetic acid and the lower exposure to 3-phenoxybenzoic acid were marginally significant, while there was also a trend towards higher internal exposure to other pollutants with organic food consumption, significant for PCB118, PCB153, and sum PCBs, and marginally significant for trans-nonachlor. Concerning breakfast cereals and muesli, no clear trends were observed.

Association between pancreatic adenocarcinoma risk and concentration of organochlorine pesticides in adipose tissue and urine: A targeted-screening analysis case-control study (PESTIPAC)

BACKGROUND

Knowledge about environmental pancreatic adenocarcinoma (PA) risk factors, including pesticide exposure, remains limited. Organochlorine (OC) accumulates in adipose tissue and can help reflect long-term exposure.

PATIENTS AND METHODS

Age and body mass index (BMI) of patients with PA were matched with those undergoing a surgery for a benign disease on age and BMI (1:1). Targeted analyses screened 345 pesticides and metabolites, including 29 OC, in adipose tissue and urine samples. The primary aim was to investigate the association between organochlorine concentrations in visceral fat or urine, and PA. Adjusted conditional logistic regressions were carried out accounting for multiple testing.

RESULTS

Trans-nonachlor (odds ratio [OR] = 1.325, 95% confidence interval [CI] [1.108-1.586]), cis-nonachlor (OR = 15.433, 95% CI [2.733-87.136]), Mirex (OR = 2.853, 95% CI [1.213-6.713]) and 4,4 DDE (OR = 1.019, 95% CI [1.005-1.034]) in fat and a greater number of positive samples (OR = 1.758 95% CI [1.11-2.997]) were significantly associated with higher odds of PA. In contrast, as awaited, urine samples did not yield any statistically significant associations for all tested pesticides.

CONCLUSION

Some OCs were associated with higher odds of PA. The underlying mechanisms of pancreatic aggression need to be investigated to refine these findings.

TRIAL REGISTRATION

Clinicaltrials.gov NCT04429490.

Genetic variants reduced POPs-related colorectal cancer risk via altering miRNA binding affinity and m6A modification

Exposure to persistent organic pollutants (POPs) may contribute to colorectal cancer risk, but the underlying mechanisms of crucial POPs exposure remain unclear. Hence, we systematically investigated the associations among POPs exposure, genetics and epigenetics and their effects on colorectal cancer. A case-control study was conducted in the Chinese population for detecting POPs levels. We measured the concentrations of 24 POPs in the plasma using gas chromatography-tandem mass spectrometry (GC-MS/MS) and evaluated the clinical significance of POPs by calculating the area under the receiver operating characteristic curve (AUC). To assess the associations between candidate genetic variants and colorectal cancer risk, unconditional logistic regression was used. Compared with healthy control individuals, individuals with colorectal cancer exhibited higher concentrations of the majority of POPs. Exposure to PCB153 was positively associated with colorectal cancer risk, and PCB153 demonstrated superior accuracy (AUC=0.72) for predicting colorectal cancer compared to other analytes. On PCB153-related genes, the rs67734009 C allele was significantly associated with reduced colorectal cancer risk and lower plasma levels of PCB153. Moreover, rs67734009 exhibited an expression quantitative trait locus (eQTL) effect on ESR1, of which the expression level was negatively related to PCB153 concentration. Mechanistically, the risk allele of rs67734009 increased ESR1 expression via miR-3492 binding and m6A modification. Collectively, this study sheds light on potential genetic and epigenetic mechanisms linking PCB153 exposure and colorectal cancer risk, thereby providing insight into the accurate protection against POPs exposure.

CXCL1/IGHG1 signaling enhances crosstalk between tumor cells and tumor-associated macrophages to promote MC-LR-induced colorectal cancer progression

Microcystin-leucine arginine (MC-LR) is a common cyantotoxin produced by hazardous cyanobacterial blooms, and eutrophication is increasing the contamination level of MC-LR in drinking water supplies and aquatic foods. MC-LR has been linked to colorectal cancer (CRC) progression associated with tumor microenvironment, however, the underlying mechanism is not clearly understood. In present study, by using GEO, KEGG, GESA and ImmPort database, MC-LR related differentially expressed genes (DEGs) and pathway- and gene set-enrichment analysis were performed. Of the three identified DEGs (CXCL1, GUCA2A and GDF15), CXCL1 was shown a positive association with tumor infiltration, and was validated to have a dominantly higher upregulation in MC-LR-treated tumor-associated macrophages (TAMs) rather than in MC-LR-treated CRC cells. Both CRC cell/macrophage co-culture and xenograft mouse models indicated that MC-LR stimulated TAMs to secrete CXCL1 resulting in promoted proliferation, migration, and invasion capability of CRC cells. Furtherly, IP-MS assay found that interaction between TAMs-derived CXCL1 and CRC cell-derived IGHG1 may enhance CRC cell proliferation and migration after MC-LR treatment, and this effect can be attenuated by silencing IGHG1 in CRC cell. In addition, molecular docking analysis, co-immunoprecipitation and immunofluorescence further proved the interactions between CXCL1 and IGHG1. In conclusion, CXCL1 secreted by TAMs can trigger IGHG1 expression in CRC cells, which provides a new clue in elucidating the mechanism of MC-LR-mediated CRC progression.

Exposure to pesticides and risk of colorectal cancer: A systematic review and meta-analysis

Colorectal cancer (CRC) is a widespread malignancy worldwide, and its relationship with pesticide exposure remains inconclusive. This study aims to elucidate the relationship between pesticide exposure and the risk of colon, rectal, or CRC, focusing on specific pesticide groups. We conducted an extensive literature search for peer-reviewed studies published up to March 31, 2023. Summary risk ratios (RR) and their corresponding 95% confidence intervals (CI) were calculated using stratified random-effects meta-analyses, taking into account different types of exposure and outcomes, and various exposed populations and pesticide subgroups. This approach aimed to address the substantial heterogeneity observed across the literature. We also assessed heterogeneity and potential small-study effects to ensure the robustness of our findings. From the 50 studies included in this review, 33 contributed to the meta-analysis. Our results indicate a significant association between herbicide exposure and colon cancer in both lifetime-days (LDs) (RR = 1.20; 95% CI = 1.01-1.42) and intensity-weighted lifetime-days (IWLDs) (RR = 1.29, 95% CI = 1.12-1.49) exposure. Similarly, insecticide exposure was associated with an increased risk of colon cancer in IWLDs (RR = 1.32; 95% CI = 1.02-1.70) exposure, and rectal cancer in any versus never exposure (RR = 1.21; 95% CI = 1.07-1.36), IDs (RR = 1.86; 95% CI = 1.30-2.67) and IWLDs (RR = 1.70; 95% CI = 1.03-2.83) exposure. While these findings suggest significant associations of herbicide and insecticide exposure with colon and rectal cancer, respectively, further research is needed to explore the impact of other pesticide groups and deepen our understanding of pesticide exposure. These results have important implications for policymakers and regulators, underscoring the need for stricter supervision and regulation of pesticide use to mitigate CRC risk.

Construction, evaluation, and AOP framework-based application of the EpPRS as a genetic surrogate for assessing environmental pollutants

BACKGROUND

Environmental pollutant measurement is essential for accurate health risk assessment. However, the detection of humans' internal exposure to pollutants is cost-intensive and consumes time and energy. Polygenic risk scores (PRSs) have been widely applied in genetic studies of complex trait diseases. It is important to construct a genetically relevant environmental surrogate for pollutant exposure and to explore its utility for disease prediction and risk assessment.

OBJECTIVES

This study enrolled 714 individuals with complete genomic data and exposomic data on 22 plasma-persistent organic pollutants (POPs).

METHODS

We first conducted 22 POP genome-wide association studies (GWAS) and constructed the corresponding environmental pollutant-based PRS (EpPRS) by clumping and P value thresholding (C + T), lassosum, and PRS-CS methods. The best-fit EpPRS was chosen by its regression R2. An adverse outcome pathway (AOP) framework was developed to assess the effects of contaminants on candidate diseases. Furthermore, Mendelian randomization (MR) analysis was performed to explore the causal association between POPs and cancer risk.

RESULTS

The C + T method produced the best-performing EpPRSs for 7 PCBs and 4 PBDEs. EpPRSs replicated the correlations of environmental exposure measurements based on consistent patterns. The diagnostic performance of type 2 diabetes mellitus (T2DM) PRS was improved by the combined model of T2DM-EpPRS of PCB126/BDE153. Finally, the AKT1-mediated AOP framework illustrated that PCB126 and BDE153 may increase the risk of T2DM by decreasing AKT1 phosphorylation through the cGMP-PKG pathway and promoting abnormal glucose homeostasis. MR analysis showed that digestive system tumors, such as colorectal cancer and biliary tract cancer, are more sensitive to POP exposure.

CONCLUSIONS

EpPRSs can serve as a proxy for assessing pollutant internal exposure. The application of the EpPRS to disease risk assessment can reveal the toxic pathway and mode of action linking exposure and disease in detail, providing a basis for the development of environmental pollutant control strategies.

Exposures to pesticides and risk of cancer: Evaluation of recent epidemiological evidence in humans and paths forward

Knowledge of the role in cancer etiology of environmental exposures as pesticides is a prerequisite for primary prevention. We review 63 epidemiological studies on exposure to pesticides and cancer risk in humans published from 2017 to 2021, with emphasis on new findings, methodological approaches, and gaps in the existing literature. While much of the recent evidence suggests causal relationships between pesticide exposure and cancer, the strongest evidence exists for acute myeloid leukemia (AML) and colorectal cancer (CRC), diseases in which the observed associations were consistent across several studies, including high-quality prospective studies and those using biomarkers for exposure assessment, with some observing dose-response relationships. Though high-quality studies have been published since the IARC monograph on organophosphate insecticides in 2017, there are still gaps in the literature on carcinogenic evidence in humans for a large number of pesticides. To further knowledge, we suggest leveraging new techniques and methods to increase sensitivity and precision of exposure assessment, incorporate multi-omics data, and investigate more thoroughly exposure to chemical mixtures. There is also a strong need for better and larger population-based cohort studies that include younger and nonoccupationally exposed individuals, particularly during developmental periods of susceptibility. Though the existing evidence has limitations, as always in science, there is sufficient evidence to implement policies and regulatory action that limit pesticide exposure in humans and, hence, further prevent a significant burden of cancers.

Associations of mitochondrial DNA copy number with incident risks of gastrointestinal cancers: A prospective case-cohort study

Epidemiological investigations implied that mitochondrial DNA copy number (mtDNAcn) variations could trigger predisposition to multiple cancers, but evidence regarding gastrointestinal cancers (GICs) was still uncertain. We conducted a case-cohort study within the prospective Dongfeng-Tongji cohort, including incident cases of colorectal cancer (CRC, n = 278), gastric cancer (GC, n = 138), and esophageal cancer (EC, n = 72) as well as a random subcohort (n = 1173), who were followed up from baseline to the end of 2018. We determined baseline blood mtDNAcn and associations of mtDNAcn with the GICs risks were estimated by using weighted Cox proportional hazards models. Significant U-shaped associations were observed between mtDNAcn and GICs risks. Compared to subjects within the second quartile (Q2) mtDNAcn subgroup, those within the 1st (Q1), 3rd (Q3), and 4th (Q4) quartile subgroups showed increased risks of CRC (hazard ratio [HR] [95% confidence interval, CI] = 2.27 [1.47-3.52], 1.65 [1.04-2.62], and 2.81 [1.85-4.28], respectively) and total GICs (HR [95%CI] = 1.84 [1.30-2.60], 1.47 [1.03-2.10], and 2.51 [1.82-3.47], respectively], and those within Q4 subgroup presented elevated GC and EC risks (HR [95% CI] = 2.16 [1.31-3.54] and 2.38 [1.13-5.02], respectively). Similar associations of mtDNAcn with CRC and total GICs risks remained in stratified analyzes by age, gender, smoking, and drinking status. This prospective case-cohort study showed U-shaped associations between mtDNAcn and GICs risks, but further research works are needed to uncover underlying biological mechanisms.

A Review of Polychlorinated Biphenyls (PCBs) Pollution in the Air: Where and How Much Are We Exposed to?

Polychlorinated biphenyls (PCBs) were widely used in industrial and commercial applications, until they were banned in the late 1970s as a result of their significant environmental pollution. PCBs in the environment gained scientific interest because of their persistence and the potential threats they pose to humans. Traditionally, human exposure to PCBs was linked to dietary ingestion. Inhalational exposure to these contaminants is often overlooked. This review discusses the occurrence and distribution of PCBs in environmental matrices and their associated health impacts. Severe PCB contamination levels have been reported in e-waste recycling areas. The occurrence of high PCB levels, notably in urban and industrial areas, might result from extensive PCB use and intensive human activity. Furthermore, PCB contamination in the indoor environment is ten-fold higher than outdoors, which may present expose risk for humans through the inhalation of contaminated air or through the ingestion of dust. In such settings, the inhalation route may contribute significantly to PCB exposure. The data on human health effects due to PCB inhalation are scarce. More epidemiological studies should be performed to investigate the inhalation dose and response mechanism and to evaluate the health risks. Further studies should also evaluate the health impact of prolonged low-concentration PCB exposure.

CCDB: A database for exploring inter-chemical correlations in metabolomics and exposomics datasets

Inter-chemical correlations in metabolomics and exposomics datasets provide valuable information for studying relationships among chemicals reported for human specimens. With an increase in the number of compounds for these datasets, a network graph analysis and visualization of the correlation structure is difficult to interpret. We have developed the Chemical Correlation Database (CCDB), as a systematic catalogue of inter-chemical correlation in publicly available metabolomics and exposomics studies. The database has been provided via an online interface to create single compound-centric views. We have demonstrated various applications of the database to explore: 1) the chemicals from a chemical class such as Per- and Polyfluoroalkyl Substances (PFAS), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phthalates and tobacco smoke related metabolites; 2) xenobiotic metabolites such as caffeine and acetaminophen; 3) endogenous metabolites (acyl-carnitines); and 4) unannotated peaks for PFAS. The database has a rich collection of 35 human studies, including the National Health and Nutrition Examination Survey (NHANES) and high-quality untargeted metabolomics datasets. CCDB is supported by a simple, interactive and user-friendly web-interface to retrieve and visualize the inter-chemical correlation data. The CCDB has the potential to be a key computational resource in metabolomics and exposomics facilitating the expansion of our understanding about biological and chemical relationships among metabolites and chemical exposures in the human body. The database is available at www.ccdb.idsl.me site.

Photo-Fenton-like degradation of antibiotics by inverse opal WO3 co-catalytic Fe2+/PMS, Fe2+/H2O2 and Fe2+/PDS processes: A comparative study

Advanced oxidation processes (AOPs) such as Fenton and Fenton-like process for pollutant removal have been widely reported. However, most papers choose one of the popular oxidants (H₂O₂, peroxymonosulfate (PMS) or peroxydisulfate (PDS)) as the oxidant via AOPs for pollutant degradation. The purpose of this work is to compare the degradation rates of the Fe²⁺/PMS, Fe²⁺/H₂O₂ and Fe²⁺/PDS processes. Furthermore, to solve the problem of slow regeneration of Fe²⁺, the visible light irradiation and inverse opal WO₃ cocatalyst were added to the Fenton/Fenton-like process. The IO WO₃ co-catalytic visible light assisted Fe²⁺/PMS, Fe²⁺/H₂O₂ and Fe²⁺/PDS processes greatly improved the degradation efficiency of norfloxacin (NOR), reaching about 30 times, 9 times and 12 times that of the homogeneous Fenton/Fenton-like process, respectively. On average, the TOC removal rates of PMS-based, H₂O₂-based and PMS-based processes for the five pollutants were 71.6%, 54.0%, and 59.6% within 60 min, and the corresponding co-catalyst treatment efficiencies were 0.215 mmol/g/h, 0.162 mmol/g/h, and 0.179 mmol/g/h, respectively. ¹O₂ and •O₂^- have been proven to play a vital role in the degradation of NOR via all the three IO WO₃ co-catalytic photo-Fenton-like processes. In addition, the effects of different reaction parameters on the activity of degrading norfloxacin were explored. The IO WO₃ co-catalytic visible light assisted Fe²⁺/PMS, Fe²⁺/H₂O₂ and Fe²⁺/PDS processes for removal of different persistent organic pollutants and norfloxacin in different actual wastewater have also been studied. Nonetheless, this study proves that IO WO₃ co-catalytic visible light assisted Fe²⁺/PMS, Fe²⁺/H₂O₂ and Fe²⁺/PDS processes could effectively remove antibiotics from wastewater.