Methodological approaches to the study of cancer risk in the vicinity of pollution sources: the experience of a population-based case-control study of childhood cancer

Maternal Exposure to Heavy Metals From Industrial Sources During Pregnancy and Childhood Cancer Risk in California

OBJECTIVE

The study investigated maternal exposure to heavy metals from industrial sources during pregnancy as potential risk factors for childhood cancer.

METHODS

Cases ages 0-19 were identified from California Cancer Registry. Controls (20:1 ratio) were randomly selected from California Birth Registry, frequency-matched by birth year (1998-2016). We estimated maternal exposure to lead, nickel, and cobalt in ambient air from the Toxics Release Inventory. We examined "ever/never" and "high/low" exposures categorized by median exposure. Models were adjusted for maternal age, race/ethnicity, method of payment for prenatal care, neighborhood socioeconomic status, and urban/rural residence.

RESULTS

Among highly exposed persons, lead was associated with an increased teratoma risk (adjusted odds ratio [aOR]: 1.52; 95% confidence interval [CI]: 0.97, 2.37), whereas nickel was associated with an increased rhabdomyosarcoma risk (aOR: 1.45; 95% CI: 1.03, 2.04). Cobalt was associated with an increased glioma risk (aOR: 2.25; 95% CI: 1.39, 3.65) among ever-exposed persons. Inverse associations were found between Wilms tumor and nickel among the ever exposed and highly exposed (ever: aOR: 0.75; 95% CI: 0.59, 0.96; high: aOR: 0.64; 95% CI: 0.45, 0.93).

CONCLUSIONS

Findings suggest that air pollution from heavy metals released by industrial sources may elevate childhood cancer risk.

Effects of urban-induced mutations on ecology, evolution and health

Increasing evidence suggests that urbanization is associated with higher mutation rates, which can affect the health and evolution of organisms that inhabit cities. Elevated pollution levels in urban areas can induce DNA damage, leading to de novo mutations. Studies on mutations induced by urban pollution are most prevalent in humans and microorganisms, whereas studies of non-human eukaryotes are rare, even though increased mutation rates have the potential to affect organisms and their populations in contemporary time. Our Perspective explores how higher mutation rates in urban environments could impact the fitness, ecology and evolution of populations. Most mutations will be neutral or deleterious, and higher mutation rates associated with elevated pollution in urban populations can increase the risk of cancer in humans and potentially other species. We highlight the potential for urban-driven increased deleterious mutational loads in some organisms, which could lead to a decline in population growth of a wide diversity of organisms. Although beneficial mutations are expected to be rare, we argue that higher mutation rates in urban areas could influence adaptive evolution, especially in organisms with short generation times. Finally, we explore avenues for future research to better understand the effects of urban-induced mutations on the fitness, ecology and evolution of city-dwelling organisms.

Maternal residential exposure to solvents from industrial sources during pregnancy and childhood cancer risk in California

BACKGROUND

Maternal solvent exposure has been suspected to increase offspring cancer risk. The study aimed to evaluate the associations between maternal residential exposure to solvents from industrial pollution during pregnancy and childhood cancer.

METHODS

The present study included 15,744 cancer cases (aged 0-19 years at diagnosis) identified from California Cancer Registry and 283,141 controls randomly selected from California Birth Registry (20:1 frequency-matched by birth year: 1998-2016). We examined industrial releases of tetrachloroethylene and 1,1,1-trichloroethane within 3 km of the birth address, while we used a 5 km buffer for carbon disulfide. We calculated the total exposure from all linked Toxic Release Inventory sites during each index pregnancy and assigned "ever/never" and "high/low exposed/unexposed" exposure, using median values. We performed quadratic decay models to estimate cancer risks associated with maternal solvent exposure in pregnancy.

RESULTS

1,1,1-Trichloroethane was associated with rhabdomyosarcoma (adjusted Odds Ratio (aOR): 1.96; 95% Confidence Interval (CI): 1.16, 3.32) in the "ever exposed" group. Ever exposure to carbon disulfide was associated with increased risks of medulloblastoma (OR = 1.85, 95% CI 1.01, 3.40) and ependymoma (OR = 1.63, 95% CI 0.97, 2.74).

CONCLUSIONS

Overall, our findings suggested maternal residential exposure to solvents from industrial sources might be associated with elevated childhood cancer risks.

Environmental Pollution and Risk of Childhood Cancer: A Scoping Review of Evidence from the Last Decade

The long-term effects of environmental pollution have been of concern as several pollutants are carcinogenic, potentially inducing a variety of cancers, including childhood cancer, which is a leading cause of death around the world and, thus, is a public health issue. The present scoping review aimed to update and summarize the available literature to detect specific environmental pollutants and their association with certain types of childhood cancer. Studies published from 2013 to 2023 regarding environmental pollution and childhood cancer were retrieved from the PubMed database. A total of 174 studies were eligible for this review and were analyzed. Our search strategy brought up most of the articles that evaluated air pollution (29%) and pesticides (28%). Indoor exposure to chemicals (11%), alcohol and tobacco use during pregnancy (16%), electromagnetic fields (12%), and radon (4%) were the subjects of less research. We found a particularly high percentage of positive associations between prenatal and postnatal exposure to indoor (84%) and outdoor (79%) air pollution, as well as to pesticides (82%), and childhood cancer. Positive associations were found between leukemia and pesticides and air pollution (33% and 27%); CNS tumors and neuroblastoma and pesticides (53% and 43%); and Wilms tumor and other rare cancers were found in association with air pollution (50%). Indoor air pollution was mostly reported in studies assessing several types of cancer (26%). Further studies are needed to investigate the mechanisms underlying the potential associations between indoor/outdoor air pollution and pesticide exposure with childhood cancer risk as more preventable measures could be taken.

Analyzing socio-environmental determinants of bone and soft tissue cancer in Indonesia

BACKGROUND

This study is designed to explore the potential impact of individual and environmental residential factors as risk determinants for bone and soft tissue cancers, with a particular focus on the Indonesian context. While it is widely recognized that our living environment can significantly influence cancer development, there has been a notable scarcity of research into how specific living environment characteristics relate to the risk of bone and soft tissue cancers.

METHODS

In a cross-sectional study, we analyzed the medical records of oncology patients treated at Prof. Suharso National Referral Orthopedic Hospital. The study aimed to assess tumor malignancy levels and explore the relationships with socio-environmental variables, including gender, distance from the sea, sunrise time, altitude, and population density. Data were gathered in 2020 from diverse sources, including medical records, Google Earth, and local statistical centers. The statistical analyses employed Chi-square and logistic regression techniques with the support of Predictive Analytics SoftWare (PASW) Statistics 18.

RESULTS

Both bivariate and multivariate analyses revealed two significant factors associated with the occurrence of bone and soft tissue cancer. Age exhibited a statistically significant influence (OR of 5.345 and a p-value of 0.000 < 0.05), indicating a robust connection between cancer development and age. Additionally, residing within a distance of less than 14 km from the sea significantly affected the likelihood of bone and soft tissue cancers OR 5.604 and p-value (0.001 < 0.05).

CONCLUSIONS

The study underscores the strong association between age and the development of these cancers, emphasizing the need for heightened vigilance and screening measures in older populations. Moreover, proximity to the sea emerges as another noteworthy factor influencing cancer risk, suggesting potential environmental factors at play. These results highlight the multifaceted nature of cancer causation and underscore the importance of considering socio-environmental variables when assessing cancer risk factors. Such insights can inform more targeted prevention and early detection strategies, ultimately contributing to improved cancer management and patient outcomes.

Childhood acute lymphoblastic leukemia survival and spatial analysis of socio-environmental risks in Mexico

Background

Acute lymphoblastic leukemia (ALL) etiology remains largely unknown; incidence patterns by age, sex, and geographical distribution suggest a potential environmental role.

Aim

To identify ALL clusters from four contrasting urban areas of Mexico and to characterize the sources of environmental carcinogens.

Methods

Hospital-based ALL cases (n = 443) diagnosed in children <19 years old from the Metropolitan Zones of Merida and San Luis Potosi, the State of Mexico, and Tijuana were analyzed (2015-2020). ALL cases were coded according to the International Classification of Diseases for Oncology. ALL clusters were identified by Kernel Density, and excess risk was estimated. Data of particulate matter ≤2.5 µm (PM2.5) concentrations measured by community-monitoring stations were analyzed. Geocoded datasets of benzene, polycyclic aromatic hydrocarbons, and PM2.5 sources were analyzed to characterize patterns of exposure in ALL clusters.

Results

The survival rate for ALL ranged from 61.5% to 78.6%. Seven ALL clusters with excess risk (RR 1.4-2.3, p < 0.05) were identified. The carcinogen sources included artisanal brick kilns, gas stations, cement works, carpentry, paint, and chemical manufacturing establishments. PM2.5 levels ranged from 15 µg/m3 to 37 µg/m3 among study areas.

Conclusion

ALL clusters were identified at the community level; the excess risk could be explained by small-scale carcinogen sources. The levels of PM2.5 in outdoor air ranged from 3 to 6 times above the World Health Organization (WHO) air quality guidelines. Healthcare providers must raise awareness of the increased risk of ALL in children living near sources of environmental carcinogens; cancer control and prevention strategies must be steered from a multi-sectoral and multi-action perspective to protect children's health.

Mammographic density in the environs of multiple industrial sources

BACKGROUND

Mammographic density (MD), defined as the percentage of dense fibroglandular tissue in the breast, is a modifiable marker of the risk of developing breast cancer. Our objective was to evaluate the effect of residential proximity to an increasing number of industrial sources in MD.

METHODS

A cross-sectional study was conducted on 1225 premenopausal women participating in the DDM-Madrid study. We calculated distances between women's houses and industries. The association between MD and proximity to an increasing number of industrial facilities and industrial clusters was explored using multiple linear regression models.

RESULTS

We found a positive linear trend between MD and proximity to an increasing number of industrial sources for all industries, at distances of 1.5 km (p-trend = 0.055) and 2 km (p-trend = 0.083). Moreover, 62 specific industrial clusters were analyzed, highlighting the significant associations found between MD and proximity to the following 6 industrial clusters: cluster 10 and women living at ≤1.5 km (β = 10.78, 95 % confidence interval (95%CI) = 1.59; 19.97) and at ≤2 km (β = 7.96, 95%CI = 0.21; 15.70); cluster 18 and women residing at ≤3 km (β = 8.48, 95%CI = 0.01; 16.96); cluster 19 and women living at ≤3 km (β = 15.72, 95%CI = 1.96; 29.49); cluster 20 and women living at ≤3 km (β = 16.95, 95%CI = 2.90; 31.00); cluster 48 and women residing at ≤3 km (β = 15.86, 95%CI = 3.95; 27.77); and cluster 52 and women living at ≤2.5 km (β = 11.09, 95%CI = 0.12; 22.05). These clusters include the following industrial activities: surface treatment of metals/plastic, surface treatment using organic solvents, production/processing of metals, recycling of animal waste, hazardous waste, urban waste-water treatment plants, inorganic chemical industry, cement and lime, galvanization, and food/beverage sector.

CONCLUSIONS

Our results suggest that women living in the proximity to an increasing number of industrial sources and those near certain types of industrial clusters have higher MD.

Residence near industrial complex and cancer incidence: A registry-based cohort of 1,022,637 participants with a follow-up of 21 years, Israel

BACKGROUND

Industrial complex (IC) residence is associated with higher cancer incidence in adults and children. However, the effect on young adults and the residence duration are not well described. Since the beginning of the 20th century, the Haifa bay area (HBA) has a major IC area with petrochemical industry complex and many other industries. The objectives of the current study were to estimate the association between IC residence and cancer incidence and to evaluate the effect of the residence duration.

METHODS

This study is a registry-based cohort (N = 1,022,637) with a follow-up of 21 years. Cox regression models were used to evaluate the associations (hazards ratios (HR) and its 95% confidence intervals (CIs)) between HBA residence and incidence of all cancer sites (n = 62,049) and for site-specific cancer types including: lung cancer (n = 5398), bladder cancer (n = 3790), breast cancer (n = 11,310), prostate cancer (n = 6389) skin cancer (n = 4651), pancreatic cancer (n = 2144) and colorectal cancer (n = 8675). We evaluated the effect of the duration of exposure as categories of 7 years for those with 15 years of follow-up.

RESULTS

IC residence was associated with higher risk for all cancer sites (HR:1.09, 95% CI: 1.06-1.12), for site-specific cancer incidence including: lung cancer (HR:1.14, 95% CI: 1.04-1.23), bladder cancer (HR:1.11, 95% CI: 1.01-1.23), breast cancer (HR:1.04, 95% CI: 0.98-1.10), prostate cancer (HR:1.07, 95% CI: 0.99-1.16), skin cancer (HR:1.22, 95% CI: 1.12-1.33) and colorectal cancer (HR:1.10, 95%CI: 1.03-1.17). Similar risk was also observed among young adults (HR: 1.10, 95% CI: 1.00-1.20). In the analyses for the duration of exposure, IC residence was associated with higher risk for all cancer site for the longest residence duration (15-21 years: HR: 1.08, 95% CI: 1.04-1.13).

CONCLUSIONS

Harmful associations were found between IC residence and incidence of all cancer sites and site-specific cancers types. Our findings add to the limited evidence of associations between IC residence and cancer in young adults.

Looking Towards 2030: Strengthening the Environmental Health in Childhood-Adolescent Cancer Survivor Programs

Childhood and adolescent cancer survivors (CACS) are a high-risk population for non-communicable diseases and secondary carcinogenesis. The Environmental and Community Health Program for Longitudinal Follow-up of CACS in the region of Murcia, Spain, is an ongoing pioneering program that constitutes a model for social innovation. This study aims to present the program tools and protocol as a whole, as well as a profile of the incidence, survival, and spatiotemporal distribution of childhood cancer in the region of Murcia, Spain, using 822 sample cases of cancer diagnosed in children under 15 years of age (1998-2020). While the crude incidence rate across that entire period was 149.6 per 1 million, there was an increase over that time in the incidence. The areas with a higher standardized incidence ratio have shifted from the northwest (1998-2003) to the southeast (2016-2020) region. Overall, the ten-year survival rate for all tumor types was 80.1% over the entire period, increasing the five-year survival rate from 76.1 (1998-2003) to 85.5 (2014-2018). CACS living in areas with very poor outdoor air quality had lower survival rates. Furthermore, integrating environmental health into clinical practice could improve knowledge of the etiology and prognosis, as well as the outcomes of CACS. Finally, monitoring individual carbon footprints and creating healthier lifestyles, alongside healthier environments for CACS, could promote wellbeing, environmental awareness, and empowerment in order to attain Sustainable Development Goals for non-communicable diseases in this population.

Toenail zinc as a biomarker: Relationship with sources of environmental exposure and with genetic variability in MCC-Spain study

BACKGROUND

Toenails are commonly used as biomarkers of exposure to zinc (Zn), but there is scarce information about their relationship with sources of exposure to Zn.

OBJECTIVES

To investigate the main determinants of toenail Zn, including selected sources of environmental exposure to Zn and individual genetic variability in Zn metabolism.

METHODS

We determined toenail Zn by inductively coupled plasma mass spectrometry in 3,448 general population controls from the MultiCase-Control study MCC-Spain. We assessed dietary and supplement Zn intake using food frequency questionnaires, residential proximity to Zn-emitting industries and residential topsoil Zn levels through interpolation methods. We constructed a polygenic score of genetic variability based on 81 single nucleotide polymorphisms in genes involved in Zn metabolism. Geometric mean ratios of toenail Zn across categories of each determinant were estimated from multivariate linear regression models on log-transformed toenail Zn.

RESULTS

Geometric mean toenail Zn was 104.1 µg/g in men and 100.3 µg/g in women. Geometric mean toenail Zn levels were 7 % lower (95 % confidence interval 1-13 %) in men older than 69 years and those in the upper tertile of fibre intake, and 9 % higher (3-16 %) in smoking men. Women residing within 3 km from Zn-emitting industries had 4 % higher geometric mean toenail Zn levels (0-9 %). Dietary Zn intake and polygenic score were unrelated to toenail Zn. Overall, the available determinants only explained 9.3 % of toenail Zn variability in men and 4.8 % in women.

DISCUSSION

Sociodemographic factors, lifestyle, diet, and environmental exposure explained little of the individual variability of toenail Zn in the study population. The available genetic variants related to Zn metabolism were not associated with toenail Zn.

Persistently high incidence rates of childhood acute leukemias from 2010 to 2017 in Mexico City: A population study from the MIGICCL

Introduction

Over the years, the Hispanic population living in the United States has consistently shown high incidence rates of childhood acute leukemias (AL). Similarly, high AL incidence was previously observed in Mexico City (MC). Here, we estimated the AL incidence rates among children under 15 years of age in MC during the period 2010-2017.

Methods

The Mexican Interinstitutional Group for the Identification of the Causes of Childhood Leukemia conducted a study gathering clinical and epidemiological information regarding children newly diagnosed with AL at public health institutions of MC. Crude age incidence rates (cAIR) were obtained. Age-standardized incidence rates worldwide (ASIRw) and by municipalities (ASIRm) were calculated by the direct and indirect methods, respectively. These were reported per million population <15 years of age; stratified by age group, sex, AL subtypes, immunophenotype and gene rearrangements.

Results

A total of 903 AL cases were registered. The ASIRw was 63.3 (cases per million) for AL, 53.1 for acute lymphoblastic leukemia (ALL), and 9.4 for acute myeloblastic leukemia. The highest cAIR for AL was observed in the age group between 1 and 4 years (male: 102.34 and female: 82.73). By immunophenotype, the ASIRw was 47.3 for B-cell and 3.7 for T-cell. The incidence did not show any significant trends during the study period. The ASIRm for ALL were 68.6, 66.6 and 62.8 at Iztacalco, Venustiano Carranza and Benito Juárez, respectively, whereas, other municipalities exhibited null values mainly for AML.

Conclusion

The ASIRw for childhood AL in MC is among the highest reported worldwide. We observed spatial heterogeneity of rates by municipalities. The elevated AL incidence observed in Mexican children may be explained by a combination of genetic background and exposure to environmental risk factors.

Cadmium (Cd) and Lead (Pb) topsoil levels and incidence of childhood leukemias

There are few well-established risk factors for childhood leukemias. While the frequency of childhood leukemias might be partially attributable to some diseases (accounting for a small fraction of cases) or ionizing radiation, the role of heavy metals has not been assessed. The objective of our study was to assess the potential association between levels of cadmium (Cd) and lead (PB) in soil and childhood leukemias incidence. We conducted a population-based case-control study of childhood leukaemia in Spain, covering 2897 incident cases gathered from the Spanish Registry of Childhood Tumours and including 14 Spanish Regions with a total population of 5,307,433 children (period 1996-2015). Cd and Pb bioavailable levels at every children's home address were estimated using data from the Geochemical Atlas of Spain. We used logistic regression to estimate odds ratios (ORs) and their 95% confidence intervals (95%CIs); we included as covariates: sex, rurality, employment rate and socioeconomic status. Metal levels were analysed according to two definitions: as continuous variable assuming linearity and as categorical variables to explore a potentially nonlinear association (quantiles). Increases in both Cd and Pb topsoil levels were associated with increased probability of childhood leukemias incidence. The results for the models with the continuous variables showed that a unit increase on the topsoil level was associated with an OR of 1.11 for Cd (95%CI 1.00-1.24) and an OR of 1.10 for Pb (95%CI 0.99-1.21). Our study may point towards a possible link between residential Cd and Pb topsoil levels and the probability of childhood leukemias incidence. Residing in a location with the highest concentrations of these heavy metals compared to those locations with the lowest could increase the risk around a 20%, for both Cd and Pb.

Residential proximity to industrial pollution and mammographic density

BACKGROUND

Mammographic density (MD), expressed as percentage of fibroglandular breast tissue, is an important risk factor for breast cancer. Our objective is to investigate the relationship between MD and residential proximity to pollutant industries in premenopausal Spanish women.

METHODS

A cross-sectional study was carried out in a sample of 1225 women extracted from the DDM-Madrid study. Multiple linear regression models were used to assess the association of MD percentage (and their 95% confidence intervals (95%CIs)) and proximity (between 1 km and 3 km) to industries included in the European Pollutant Release and Transfer Register.

RESULTS

Although no association was found between MD and distance to all industries as a whole, several industrial sectors showed significant association for some distances: "surface treatment of metals and plastic" (β = 4.98, 95%CI = (0.85; 9.12) at ≤1.5 km, and β = 3.00, 95%CI = (0.26; 5.73) at ≤2.5 km), "organic chemical industry" (β = 6.73, 95%CI = (0.50; 12.97) at ≤1.5 km), "pharmaceutical products" (β = 4.14, 95%CI = (0.58; 7.70) at ≤2 km; β = 3.55, 95%CI = (0.49; 6.60) at ≤2.5 km; and β = 3.11, 95%CI = (0.20; 6.01) at ≤3 km), and "urban waste-water treatment plants" (β = 8.06, 95%CI = (0.82; 15.30) at ≤1 km; β = 5.28; 95%CI = (0.49; 10.06) at ≤1.5 km; β = 4.30, 95%CI = (0.03; 8.57) at ≤2 km; β = 5.26, 95%CI = (1.83; 8.68) at ≤2.5 km; and β = 3.19, 95%CI = (0.46; 5.92) at ≤3 km). Moreover, significant increased MD was observed in women close to industries releasing specific pollutants: ammonia (β = 4.55, 95%CI = (0.26; 8.83) at ≤1.5 km; and β = 3.81, 95%CI = (0.49; 7.14) at ≤2 km), dichloromethane (β = 3.86, 95%CI = (0.00; 7.71) at ≤2 km), ethylbenzene (β = 8.96, 95%CI = (0.57; 17.35) at ≤3 km), and phenols (β = 2.60, 95%CI = (0.21; 5.00) at ≤2.5 km).

CONCLUSIONS

Our results suggest no statistically significant relationship between MD and proximity to industries as a whole, although we detected associations with various industrial sectors and some specific pollutants, which suggests that MD could have a mediating role in breast carcinogenesis.

Particulate Air Pollution and Osteoporosis: A Systematic Review

Air pollution is associated with inflammation and oxidative stress, which predispose to several chronic diseases in human. Emerging evidence suggests that the severity and progression of osteoporosis are directly associated with inflammation induced by air pollutants like particulate matter (PM). This systematic review examined the relationship between PM and bone health or fractures. A comprehensive literature search was conducted from January until February 2021 using the PubMed, Scopus, Web of Science, Google Scholar and Cochrane Library databases. Human cross-sectional, cohort and case-control studies were considered. Of the 1500 papers identified, 14 articles were included based on the inclusion and exclusion criteria. The air pollution index investigated by most studies were PM2.5 and PM10. Current studies demonstrated inconsistent associations between PM and osteoporosis risk or fractures, which may partly due to the heterogeneity in subjects' characteristics, study design and analysis. In conclusion, there is an inconclusive relationship between osteoporosis risk and fracture and PM exposures which require further validation.

Risk of gastric cancer in the environs of industrial facilities in the MCC-Spain study

BACKGROUND

Gastric cancer is the fifth most frequent tumor worldwide. In Spain, it presents a large geographic variability in incidence, suggesting a possible role of environmental factors in its etiology. Therefore, epidemiologic research focused on environmental exposures is necessary.

OBJECTIVES

To assess the association between risk of gastric cancer (by histological type and tumor site) and residential proximity to industrial installations, according to categories of industrial groups and specific pollutants released, in the context of a population-based multicase-control study of incident cancer conducted in Spain (MCC-Spain).

METHODS

In this study, 2664 controls and 137 gastric cancer cases from 9 provinces, frequency matched by province of residence, age, and sex were included. Distances from the individuals' residences to the 106 industries located in the study areas were computed. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs) for categories of distance (from 1 km to 3 km) to industries, adjusting for matching variables and potential confounders.

RESULTS

Overall, no excess risk of gastric cancer was observed in people living close to the industrial installations, with ORs ranging from 0.73 (at ≤2.5 km) to 0.93 (at ≤1.5 km). However, by industrial sector, excess risks (OR; 95%CI) were found near organic chemical industry (3.51; 1.42-8.69 at ≤2 km), inorganic chemical industry (3.33; 1.12-9.85 at ≤2 km), food/beverage sector (2.48; 1.12-5.50 at ≤2 km), and surface treatment using organic solvents (3.59; 1.40-9.22 at ≤3 km). By specific pollutant, a statistically significant excess risk (OR; 95%CI) was found near (≤3 km) industries releasing nonylphenol (6.43; 2.30-17.97) and antimony (4.82; 1.94-12.01).

CONCLUSIONS

The results suggest no association between risk of gastric cancer and living in the proximity to the industrial facilities as a whole. However, a few associations were detected near some industrial sectors and installations releasing specific pollutants.

The self-reported behaviour of Iiyiyiu Aschii Cree and the worry about pollution from industrial and hydroelectric development in northern Quebec, Canada

Worry is influenced by environmental pollution and affects individual health and well-being; however, little is known about this association in Indigenous communities. Using logistic regression models, we examined self-reported responses among Cree adults to the question "Are you worried about the pollution of the environment (land, water or air) in Iiyiyiu Aschii?" to assess if increased worry was associated with proximity to industrial and hydroelectric development, whether increased worry was associated with self-reported behavioural changes of water consumption type in the community or bush, and days spent on-the-land. Proximity to multiple industrial and hydroelectric development sites was associated with increased worry about pollution. Notably, the decreased consumption of tap water in the community was significantly associated with increased worry, but time-on-the land was not. Overall, our study provides new findings concerning development in a Cree territory in northern Quebec, Canada, and the worry about pollution's association with self-reported behavioural changes.

Residential proximity to industrial pollution sources and colorectal cancer risk: A multicase-control study (MCC-Spain)

BACKGROUND

Colorectal cancer is the third most frequent tumor in males and the second in females worldwide. In Spain, it is an important and growing health problem, and epidemiologic research focused on potential risk factors, such as environmental exposures, is necessary.

OBJECTIVES

To analyze the association between colorectal cancer risk and residential proximity to industries, according to pollution discharge route, industrial groups, categories of carcinogens and other toxic substances, and specific pollutants released, in the context of a population-based multicase-control study of incident cancer carried out in Spain (MCC-Spain).

METHODS

MCC-Spain included 557 colorectal cancer cases and 2948 controls in 11 provinces, frequency matched by sex, age, and region of residence. Distances were computed from subjects' residences to each of the 134 industries located in the study area. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs) for categories of distance (from 1 km to 3 km) to industrial facilities, adjusting for matching variables and other confounders.

RESULTS

Excess risk (OR; 95%CI) of colorectal cancer was detected near industries overall for all distances analyzed, from 1 km (2.03; 1.44-2.87) to 3 km (1.26; 1.00-1.59). In general, industries releasing pollutants to air showed higher excess risks than facilities releasing pollution to water. By industrial sector, excess risk (OR; 95%CI) was found near (≤3 km) production of metals (2.66; 1.77-4.00), surface treatment of metals (1.48; 1.08-2.02), glass and mineral fibers (2.06; 1.39-3.07), organic chemical industry (4.80; 3.20-7.20), inorganic chemical industry (6.74; 4.38-10.36), food/beverage sector (3.34; 2.38-4.68), and surface treatment using organic solvents (6.16; 4.06-9.36). By pollutants, the main excess risks (OR; 95%CI) were found near (≤3 km) industries releasing nonylphenol (9.19; 5.91-14.28), antimony (5.30; 3.45-8.15), naphthalene (3.11; 2.16-4.49), organotin compounds (2.64; 1.76-3.98), manganese (2.53; 1.63-3.93), dichloromethane (2.52; 1.74-3.66), and vanadium (2.49; 1.59-3.91).

CONCLUSIONS

Our results support the hypothesis that residing in the proximity of industries may be a risk factor for colorectal cancer.

Validation of self-reported perception of proximity to industrial facilities: MCC-Spain study

BACKGROUND

Self-reported data about environmental exposures can lead to measurement error.

OBJECTIVES

To validate the self-reported perception of proximity to industrial facilities.

METHODS

MCC-Spain is a population-based multicase-control study of cancer in Spain that recruited incident cases of breast, colorectal, prostate, and stomach cancer. The participant's current residence and the location of the industries were geocoded, and the linear distance between them was calculated (gold standard). The epidemiological questionnaire included a question to determine whether the participants perceived the presence of any industry at ≤1 km from their residences. Sensitivity and specificity of individuals' perception of proximity to industries were estimated as measures of classification accuracy, and the area under the curve (AUC) and adjusted odds ratios (aORs) of misclassification were calculated as measures of discrimination. Analyses were performed for all cases and controls, and by tumor location, educational level, sex, industrial sector, and length of residence. Finally, aORs of cancer associated with real and self-reported distances were calculated to explore differences in the estimation of risk between these measures.

RESULTS

Sensitivity of the questionnaire was limited (0.48) whereas specificity was excellent (0.89). AUC was sufficient (0.68). Participants with breast (aOR(95%CI) = 2.03 (1.67;2.46)), colorectal (aOR(95%CI) = 1.41 (1.20;1.64)) and stomach (aOR(95%CI) = 1.59 (1.20;2.10)) cancer showed higher risk of misclassification than controls. This risk was higher for lower educational levels (aOR_{<primaryvs.university} (95%CI) = 1.78 (1.44;2.20)), among younger participants (aOR_{22-54 yearsvs. 73-85 years} (95%CI) = 1.32 (1.09;1.60)), and for some industrial sectors: pharmaceutical (aOR(95%CI) = 29.02 (19.52;43.14)), galvanization (aOR(95%CI) = 14.14 (6.78;29.47)), and ceramic (aOR(95%CI) = 12.73 (7.22;22.44)). Participants living ≤1 year in the study area showed a lower risk of misclassification ((aOR_{≤1vs.>15 years} (95%CI) = 0.56 (0.36;0.85)). The use of self-reported proximity vs. real distance to industrial facilities biased the effect on cancer risk towards the nullity.

CONCLUSIONS

Self-reported distance to industrial facilities can be a useful tool for hypothesis generation, but hypothesis-testing studies should use real distance to report valid conclusions. The sensitivity of the question might be improved with a more specific formulation.