Association of Ambient Fine Particulate Matter (PM2.5) with Elevated Fecal Hemoglobin Concentration and Colorectal Carcinogenesis: A Population-Based Retrospective Cohort Study

An ecological analysis of associations between ambient air pollution and cancer incidence rates in Taiwan

Air pollution is deemed a human carcinogen and can be linked to certain types of cancer other than lung cancer. The present study aimed to investigate the pollutant-cancer associations in a population-level cohort. We obtained the annual age-standardized incidence rates of 28 different cancer types between 2015 to 2019 from the Taiwan Cancer Registry. Outdoor concentrations of particulate matter with a diameter of 10 μm or less (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), ground-level ozone (O3), and carbon monoxide (CO) between 2001 to 2010 were retrieved from the Taiwan Air Quality Monitoring Network. Weighted quantile sum (WQS) regression models were used to determine the combined effects of five air pollutants on the relationship to cancer incidence rates after controlling for sex ratio, age, average disposable income per household, overweight/obesity prevalence, current smoking rate, and drinking rate. Trend analyses showed that NO2 and CO concentrations tended to decrease, while SO2 concentrations increased in some counties. WQS regression analyses revealed significantly positive correlations between air pollutants and liver cancer, lung and tracheal cancer, colorectal cancer, thyroid cancer, kidney cancer, and small intestine cancer. Altogether, the results from this ecological study unravel that exposure to ambient air pollution is associated with the incidence of several non-lung cancer types.

The emerging role of hypoxia and environmental factors in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic and debilitating disorder characterized by inflammation of the gastrointestinal tract. Despite extensive research, the exact cause of IBD remains unknown, hampering the development of effective therapies. However, emerging evidence suggests that hypoxia, a condition resulting from inadequate oxygen supply, plays a crucial role in intestinal inflammation and tissue damage in IBD. Hypoxia-inducible factors (HIFs), transcription factors that regulate the cellular response to low oxygen levels, have gained attention for their involvement in modulating inflammatory processes and maintaining tissue homeostasis. The two most studied HIFs, HIF-1α and HIF-2α, have been implicated in the development and progression of IBD. Toxicological factors encompass a wide range of environmental and endogenous agents, including dietary components, microbial metabolites, and pollutants. These factors can profoundly influence the hypoxic microenvironment within the gut, thereby exacerbating the course of IBD and fostering the progression of colitis-associated colorectal cancer. This review explores the regulation of hypoxia signaling at the molecular, microenvironmental, and environmental levels, investigating the intricate interplay between toxicological factors and hypoxic signaling in the context of IBD, focusing on its most concerning outcomes: intestinal fibrosis and colorectal cancer.

Associations between fine particulate matter and colorectal cancer: a systematic review and meta-analysis

Colorectal cancer (CRC) is the second deadliest cancer worldwide. The impact of fine particulate matter (PM2.5) on many diseases is a global concern, yet its association with CRC is unclear. This study aimed to assess the effect of PM2.5 exposure on CRC. We searched PubMed, Web of Science, and Google Scholar databases for population-based articles published before September 2022, providing risk estimates with 95% confidence intervals (CI). Among 85,743 articles, we identified 10 eligible studies across multiple countries and regions in North America and Asia. We calculated the overall risk, incidence and mortality and performed subgroup analyses according to countries and regions. The results revealed an association between PM2.5 and increased risk of CRC (total risk, 1.19 [95% CI 1.12-1.28]; incidence, OR=1.18 [95% CI 1.09-1.28]; mortality, OR=1.21 [95% CI 1.09-1.35]). The elevated risks of CRC associated with PM2.5 were different across countries and regions, at 1.34 [95% CI 1.20-1.49], 1.00 [95% CI 1.00-1.00], 1.08 [95% CI 1.06-1.10], 1.18 [95% CI 1.07-1.29], 1.01 [95% CI 0.79-1.30], in the United States, China, Taiwan, Thailand, and Hong Kong, respectively. Incidence and mortality risks were higher in North America than those in Asia. In particular, the incidence and mortality were highest in the United States (1.61 [95% CI 1.38-1.89] and 1.29 [95% CI 1.17-1.42], respectively) than those in other countries. This study is the first comprehensive meta-analysis to find a strong association between PM2.5 exposure and increased CRC risk.

Faecal haemoglobin concentrations are associated with all-cause mortality and cause of death in colorectal cancer screening

BACKGROUND

Colorectal cancer (CRC) screening reduces all-cause and CRC-related mortality. New research demonstrates that the faecal haemoglobin concentration (f-Hb) may indicate the presence of other serious diseases not related to CRC. We investigated the association between f-Hb, measured by a faecal immunochemical test (FIT), and both all-cause mortality and cause of death in a population-wide cohort of screening participants.

METHODS

Between 2014 and 2018, 1,262,165 participants submitted a FIT for the Danish CRC screening programme. We followed these participants, using the Danish CRC Screening Database and several other national registers on health and population, until December 31, 2018. We stratified participants by f-Hb and compared them using a Cox proportional hazards regression on all-cause mortality and cause of death reported as adjusted hazard ratios (aHRs). We adjusted for several covariates, including comorbidity, socioeconomic factors, demography and prescription medication.

RESULTS

We observed 21,847 deaths in the study period. Our multivariate analyses indicated an association relationship between increasing f-Hb and the risk of dying in the study period. This risk increased steadily from aHR 1.38 (95% CI: 1.32, 1.44) in those with a f-Hb of 7.1-11.9 μg Hb/g faeces to 2.20 (95% CI: 2.10, 2.30) in those with a f-Hb ≥60.0 μg Hb/g faeces, when compared to those with a f-Hb ≤7.0 μg Hb/g faeces. The pattern remained when excluding CRC from the analysis. Similar patterns were observed between incrementally increasing f-Hb and the risk of dying from respiratory disease, cardiovascular disease and cancers other than CRC. Furthermore, we observed an increased risk of dying from CRC with increasing f-Hb.

CONCLUSIONS

Our findings support the hypothesis that f-Hb may indicate an elevated risk of having chronic conditions if causes for the bleeding have not been identified. The mechanisms still need to be established, but f-Hb may be a potential biomarker for several non-CRC diseases.

The spatiotemporal correlation of PM2.5 concentration on esophageal cancer hospitalization rate in Fujian province of China

This paper aimed to explore the correlation between PM_2.5 concentration and hospitalization rate of esophageal cancer in Fujian province, and tried to find out the accurate lag effect between PM_2.5 and hospitalization rate in 70 counties from the linear and nonlinear aspects. We extracted inpatients data of esophageal cancer from the New Rural Cooperative Medical Scheme (NRCMS) database and air pollutant PM_2.5 grid data published by the atmospheric composition analysis group. The study showed that the hospitalization rate of esophageal cancer presented spatial aggregation in 70 counties of Fujian province. Southeast urban agglomerations had high hospitalization rates, while central and western regions had low hospitalization rates. The study found that the spatial distribution of the hospitalization rate of esophageal cancer in 2016 was not consistent with that of the PM_2.5 concentration in the same year. The concentration of PM_2.5 in 2003 and 2004 had the strongest correlation with the hospitalization rate of esophageal cancer in 2016, with Pearson correlation coefficient r value of - 0.365 and Geodetector q-statistic value of 0.148 (p < 0.05). Our findings showed that there existed a 13-year lag period of air pollutant PM_2.5 on the esophageal cancer hospitalization rate, which can provide helpful guidance in the early screening strategy of esophageal cancer in Fujian. The research progress of this paper will help to understand the lag period of the impact of air pollutants on the hospitalization rate of esophageal cancer, provide valuable information for the prevention and treatment strategy of esophageal cancer in Fujian province, and provide relevant experience for alike regions.

Faecal Haemoglobin Estimated by Faecal Immunochemical Tests-An Indicator of Systemic Inflammation with Real Clinical Potential

Multimorbidity is the major cause of ill-health and premature death in developed countries. The ability to identify individuals at risk of developing chronic disease, particularly multimorbidity, reliably, and simply, and to identify undiagnosed disorders, is vital to reducing the global burden of disease. This narrative review, the first of recent studies, demonstrates that raised faecal haemoglobin concentration (f-Hb) is associated with increased all-cause and cause-specific mortality and with longer-term conditions including diabetes, hypertension, cardiovascular disease, and psoriasis, and with probable intake of particulate matter. We and others have hypothesized that elevated f-Hb (measured using a faecal immunochemical test) has considerable potential to identify individuals at risk of, or who already have, early stage, undiagnosed chronic disease. If f-Hb does prove to be an effective biomarker for chronic disease and multimorbidity, individuals with detectable f-Hb, but without an obvious source of gastrointestinal blood loss, could benefit from further assessment and early intervention. To test this hypothesis rigorously, longitudinal data-linkage methodology is required linking colorectal cancer screening data, and data on patients presenting with lower gastrointestinal symptoms, with routinely collected health information.