Multiple xenoestrogen air pollutants and breast cancer risk: Statistical approaches to investigate combined exposures effect

Studies suggested that exposure to air pollutants, with endocrine disrupting (ED) properties, have a key role in breast cancer (BC) development. Although the population is exposed simultaneously to a mixture of multiple pollutants and ED pollutants may act via common biological mechanisms leading to synergic effects, epidemiological studies generally evaluate the effect of each pollutant separately. We aimed to assess the complex effect of exposure to a mixture of four xenoestrogen air pollutants (benzo-[a]-pyrene (BaP), cadmium, dioxin (2,3,7,8-Tétrachlorodibenzo-p-dioxin TCDD)), and polychlorinated biphenyl 153 (PCB153)) on the risk of BC, using three recent statistical methods, namely weighted quantile sum (WQS), quantile g-computation (QGC) and Bayesian kernel machine regression (BKMR). The study was conducted on 5222 cases and 5222 matched controls nested within the French prospective E3N cohort initiated in 1990. Annual average exposure estimates to the pollutants were assessed using a chemistry transport model, at the participants' residence address between 1990 and 2011. We found a positive association between the WQS index of the joint effect and the risk of overall BC (adjusted odds ratio (OR) = 1.10, 95% confidence intervals (CI): 1.03-1.19). Similar results were found for QGC (OR = 1.11, 95%CI: 1.03-1.19). Despite the association did not reach statistical significance in the BKMR model, we observed an increasing trend between the joint effect of the four pollutants and the risk of BC, when fixing other chemicals at their median concentrations. BaP, cadmium and PCB153 also showed positive trends in the multi-pollutant mixture, while dioxin showed a modest inverse trend. Despite we found a clear evidence of a positive association between the joint exposure to pollutants and BC risk only from WQS and QGC regression, we observed a similar suggestive trend using BKMR. This study makes a major contribution to the understanding of the joint effects of air pollution.

Occupational exposure to organic solvents and the risk of developing testicular germ cell tumors (TESTIS study): Effect of combined exposure assessment on risk estimation

OBJECTIVES

Etiological factors of testicular germ cell tumors (TGCT) remain largely unknown, but a causal role of occupational exposures to solvents has been suggested. Previous studies analyzing these exposures reported discordant results, potentially related to exposure assessment methods. The aim of this study was to investigate the role of occupational exposure to solvents on the risk of developing TGCT among young men.

METHODS

This study examined occupational exposures to solvents and TGCT risk based on the lifetime work histories of 454 cases and 670 controls, aged 18-45 years, of the French national TESTIS case-control study. Solvent exposure was estimated using: (i) exposure assignment by job-exposure matrix (JEM) and (ii) JEM combined with self-reported exposure data from specific questionnaires (SQ) and expert assessment (EA). Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression models.

RESULTS

Both approaches (JEM and JEM+SQ+EA) showed a consistent association between TGCT and trichloroethylene exposure (exposed versus not exposed; JEM=OR 1.80 [95% confidence interval (CI) 1.12-2.90] and JEM+SQ+EA= OR 2.59 (95% CI 1.42-4.72). Both approaches also observed positive associations with ketone esters and fuels & petroleum-based solvents.

CONCLUSION

The results suggest that some organic solvents might be involved in the pathogenesis of TGCT among occupationally exposed men. The combined use of JEM+SQ+EA seemed to limit misclassification by considering individual exposure variability and is, therefore, an appealing approach to assess occupational exposures in epidemiological studies.

An Integrated Cancer Prevention Strategy: the Viewpoint of the Leon Berard Comprehensive Cancer Center Lyon, France

This article describes some of the key prevention services in the Leon Berard Comprehensive Cancer Center (CLB) Lyon, France, which are based on clinical prevention services, outreach activities, and collaboration with professional and territorial health communities. In addition, research is embedded at all stages of the prevention continuum, from understanding cancer causes through to the implementation of prevention interventions during and after cancer. Health promotion activities in the community and dedicated outpatient primary cancer prevention services for individuals at increased risk have been implemented. The CLB's experience illustrates how prevention can be integrated into the comprehensive mission of cancer centers, and how in turn, the cancer centers may contribute to bridging the current fragmentation between cancer care and the different components of primary, secondary, and tertiary prevention. With increasing cancer incidence, the shift toward integrated prevention-centered cancer care is not only key for improving population health, but this may also provide a response to the shortage of hospital staff and overcrowding in cancer services, as well as offer opportunities to reduce carbon emissions from cancer care.

[Cancer causes: what levers for primary prevention?]

CANCER CAUSES

WHAT LEVERS FOR PRIMARY PREVENTION? Facing the continuous increase in cancer incidence, mobilizing efficient levers to act upstream of the disease is a major public health issue. Accelerating the transfer into practice of the continuous enrichment of the understanding of the multifactorial causes of cancers constitutes a first lever of prevention. This also requires a strengthening of the involvement of all actors and stakeholders, beyond the health and medico-social sectors. In order to guide practices, this article reviews the proportion of cancers attributable to the main lifestyle and environmental factors and causes, provides an update on cancers linked to heredity and the French oncogenetic organisation, addresses the specific issue of work related exposures and occupational cancers, proposes a prioritization of actions to break with the current fragmentation of prevention, in particular through improving the articulation of population-based interventions with targeted and personalized approaches, and better considering individuals in their environments.

Association between cumulative airborne dioxin exposure and non-Hodgkin's lymphoma risk in a nested case-control study within the French E3N cohort

BACKGROUND

Dioxins are a family of chemical molecules that are chlorinated, lipophilic, and bio-accumulative. They are thought to enhance the risk of non-lymphoma Hodgkin's due to their known carcinogenic properties (NHL). This is the first epidemiological research to investigate the relationship between repeated emissions of airborne dioxin exposure and the risk of NHL.

OBJECTIVE

A case-control study nested within the French E3N cohort of 98,995 women covered by the health insurance provider of the national education system evaluated the association between cumulative airborne dioxin exposure and NHL risk.

MATERIALS AND METHODS

NHL incident cases (368) and controls (368) were compared. Over the duration of the study, participants' residential histories and the locations of industrial sites were gathered (1990-2008). Using a Geographic Information System (GIS)-based exposure index, the cumulative exposure to airborne dioxins for each participant was calculated at the individual address level. The odds ratios (OR) and 95 % confidence intervals (CI) were calculated using multivariable conditional logistic regression models (CI).

RESULTS

The log-transformed continuous cumulative dioxin exposure index was substantially correlated with the risk of NHL (OR1.2 (95 % CI 1.0,1.4) for an increase in log-TEQ/m2 of 4.4, or one standard deviation). The combined chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) subtype was significantly associated with NHL histological subtypes (OR 1.6 (95 % CI 1.1,2.3)).

CONCLUSION

The findings of this study demonstrate a significant positive correlation between cumulative airborne dioxin exposure and the risk of NHL in women, and more specifically, a significant positive association for the CLL & SLL subtype. These results help to support the attempts to reduce the exposure to dioxins in the air.

Parental occupational exposure to solvents and risk of developing testicular germ cell tumors among sons: a French nationwide case-control study (TESTIS study)

OBJECTIVES

The etiology of testicular germ cell tumors (TGCT) is suspected to be related to prenatal environmental risk factors. Some solvents have potential endocrine disrupting or carcinogenic properties and may disrupt male genital development in utero. The aim of this study was to examine the association between parental occupational exposure to solvents and TGCT risk among their offspring.

METHODS

A French nationwide case-control study, TESTIS included 454 TGCT cases and 670 controls frequency-matched on region and 5-year age strata. Participants were interviewed via telephone and provided information on parental occupations at birth. Job-exposure matrices (JEM) developed in the French Matgéné program were used to assign exposure to five petroleum-based solvents, five solvents or groups of oxygenated solvents, and five chlorinated solvents. Odds ratios (OR) for TGCT and 95% confidence intervals (CI) were estimated using conditional logistic regression, adjusting for TGCT risk factors.

RESULTS

Occupational exposure to at least one solvent during the year of their son's birth was 41% among fathers and 21% among mothers. Paternal exposure to at least one solvent showed OR 0.89 (95% CI 0.68-1.15). Exposure to perchloroethylene (OR 1.41, 95% CI 0.55-3.61), methylene chloride (OR 1.13, 95% CI 0.54-2.34) and diesel/kerosene/fuel oil (OR 1.17, 95% CI 0.80-1.73) disclosed OR >1 but with low precision. Our results suggest a possible modest increase in non-seminoma risk for sons whose fathers were highly exposed to trichloroethylene (OR 1.44, 95% CI 0.79-2.63). Maternal exposure to at least one solvent showed OR 0.90 (95% CI 0.65-1.24). When stratifying by birth year, men born in the 1970s experienced an increased TGCT risk following maternal exposure to fuels and petroleum-based solvents (OR 2.74, 95% CI 1.11-6.76).

CONCLUSION

Overall, no solid association was found between parental occupational exposure to solvents and TGCT risk. The association found with maternal occupational exposure to fuels and petroleum solvents among older men needs further investigation.

A Multicenter Study to Assess a Systematic Screening of Occupational Exposures in Lung Cancer Patients

Occupational lung cancer cases remain largely under-reported and under-compensated worldwide. In order to improve the detection and compensation of work-related lung cancers, we implemented a systematic screening of occupational exposures, combining a validated self-administered questionnaire to assess occupational exposures and a specialized occupational cancer consultation. After a pilot study, the present prospective, open-label, scale-up study aimed to assess this systematic screening of occupational exposures in lung cancer patients in five sites in France by associating university hospitals with cancer centers. Patients with lung cancer were sent a self-administered questionnaire to collect their job history and potential exposure to lung carcinogens. The questionnaire was assessed by a physician to determine if a specialized occupational cancer consultation was required. During the consultation, a physician assessed if the lung cancer was occupation-related and, if it was, delivered a medical certificate to claim for compensation. Patients were offered help from a social worker for the administrative procedure. Over 15 months, 1251 patients received the questionnaire and 462 returned it (37%). Among them, 176 patients (38.1%) were convened to the occupational cancer consultation and 150 patients attended the consultation. An exposure to occupational lung carcinogen was identified in 133 patients and a claim for compensation was judged possible for 90 patients. A medical certificate was delivered to 88 patients and 38 patients received compensation. Our national study demonstrated that a systematic screening of occupational exposures is feasible and will bring a significant contribution to improve the detection of occupational exposures in lung cancer patients.

Occupational asbestos exposure and survival among lung cancer patients

OBJECTIVE

This study investigated the association between occupational asbestos exposure (OAE) and survival in patients with histologically confirmed lung cancer (LC).

METHODS

This monocentric study was conducted in the Comprehensive Cancer Centre Léon Bérard, Lyon, France. A systematic screening has been in place since 2014 for occupational exposure to carcinogens using a self-assessment questionnaire sent to all patients newly diagnosed with histologically confirmed LC identified through the multidisciplinary LC board from 2014 to 2019. When the physician suspected a work-related exposure from the questionnaire including job history, an occupational cancer consultation was carried out to detail carcinogen exposures and assess if the LC was work-related. Demographics, clinical characteristics and survival data were extracted from medical records. The association between asbestos exposure and overall survival (hazard ratio and 95% confidence intervals) was estimated by Cox proportional hazards regression.

RESULTS

Overall, 702 patients were eligible to the present study, including 180 patients with OAE. In the crude analysis, LCs assessed as moderately or highly attributable to OAE were associated with decreased overall survival (HR = 1.32, 95 %CI 1.04-1.67) compared to LC without OAE or with a low degree of imputability to OAE (median follow-up 28.8 months). After adjustment for confounding (age at diagnosis, smoking status, stage, brain metastasis at diagnosis, and histology), the association of OAE with overall survival was no longer statistically significant (HR = 1.21, 95 %CI 0.94-1.56).

CONCLUSION

Overall survival in occupationally asbestos exposed LC patients may be decreased in comparison with non-exposed LC patients, warranting further investigations in larger studies.

Traffic-Related Air Pollution and Breast Cancer Risk: A Systematic Review and Meta-Analysis of Observational Studies

Current evidence of an association of breast cancer (BC) risk with air pollution exposure, in particular from traffic exhaust, remains inconclusive, and the exposure assessment methodologies are heterogeneous. This study aimed to conduct a systematic review and meta-analysis on the association between traffic-related air pollution (TRAP) and BC incidence (PROSPERO CRD42021286774). We systematically reviewed observational studies assessing exposure to TRAP and BC risk published until June 2022, available on Medline/PubMed and Web of Science databases. Studies using models for assessing exposure to traffic-related air pollutants or using exposure proxies (including traffic density, distance to road, etc.) were eligible for inclusion. A random-effects meta-analysis of studies investigating the association between NO₂/NO_x exposure and BC risk was conducted. Overall, 21 studies meeting the inclusion criteria were included (seven case-control, one nested case-control, 13 cohort studies); 13 studies (five case-control, eight cohort) provided data for inclusion in the meta-analyses. Individual studies provided little evidence of an association between TRAP and BC risk; exposure assessment methods and time periods of traffic emissions were different. The meta-estimate on NO₂ exposure indicated a positive association (pooled relative risk per 10 µg/m³ of NO₂: 1.015; 95% confidence interval, CI: 1.003; 1.028). No association between NO_x exposure and BC was found (three studies). Although there was limited evidence of an association for TRAP estimated with proxies, the meta-analysis showed a significant association between NO₂ exposure, a common TRAP pollutant marker, and BC risk, yet with a small effect size. Our findings provide additional support for air pollution carcinogenicity.

Long-term exposure to nitrogen dioxide air pollution and breast cancer risk: A nested case-control within the French E3N cohort study

Nitrogen dioxide (NO₂) is an important air pollutant due to its adverse effects on human health. Yet, current evidence on the association between NO₂ and the risk of breast cancer lacks consistency. In this study, we investigated the association between long-term exposure to NO₂ and breast cancer risk in the French E3N cohort study. Association of breast cancer risk with NO₂ exposure was assessed in a nested case-control study within the French E3N cohort including 5222 breast cancer cases identified over the 1990-2011 follow-up period and 5222 matched controls. Annual mean concentrations of NO₂ at participants' residential addresses for each year from recruitment 1990 through 2011, were estimated using a land use regression (LUR) model. Multivariable conditional logistic regression models were used to compute odds ratios (ORs) and their 95% confidence intervals (CIs). Additional analyses were performed using NO₂ concentrations estimated by CHIMERE, a chemistry transport model. Overall, the mean NO₂ exposure was associated with an increased risk of breast cancer. In all women, for each interquartile range (IQR) increase in NO₂ levels (LUR: 17.8 μg/m³), the OR of the model adjusted for confounders was 1.09 (95% CI: 1.01-1.18). The corresponding OR in the fully adjusted model (additionally adjusted for established breast cancer risk factors) was 1.07 (95% CI: 0.98-1.15). By menopausal status, results for postmenopausal women were comparable to those for all women, while no association was observed among premenopausal women. By hormone receptor status, the OR of estrogen receptor positive breast cancer = 1.07 (95% CI: 0.97-1.19) in the fully adjusted model. Additional analyses using the CHIMERE model showed slight differences in ORs estimates. The results of this study indicate an increased risk of breast cancer associated with long-term exposure to NO₂ air pollution. Observing comparable effects of NO₂ exposure estimated by two different models, reinforces these findings.

Paternal Occupational Exposure to Heavy Metals and Welding Fumes and Testicular Germ Cell Tumours in Sons in France

Testicular cancer is the most common cancer in young men. Its causes are largely unknown, although prenatal occupational and environmental exposures have been suggested. We investigated paternal occupational exposure to heavy metals and welding fumes and the risk of testicular germ cell tumors (TGCT) in their offspring. A total of 454 cases and 670 controls were included from a French nationwide case-control study. The INTEROCC job exposure matrix was used to assign occupational exposures (cadmium, chromium, iron, nickel, lead, and welding fumes) to the fathers' jobs. Odds ratios (ORs) for TGCT were estimated using conditional logistic regression models for frequency-matched sets. Three complementary analytical approaches were used: (1) single-agent analysis, (2) analysis by groups, and (3) principal component analysis (PCA). The proportion of paternal exposure to different heavy metals and welding fumes ranged from 0.7% (cadmium) to 11.3% (lead). Based on PCA, three principal components explained 93.5% of the cumulative variance. No associations were found between heavy metals or welding fumes and TGCT. In this study, paternal occupational exposure to heavy metals or welding fumes was not associated with TGCT development in their sons.

The impact of left truncation of exposure in environmental case-control studies: evidence from breast cancer risk associated with airborne dioxin

In epidemiology, left-truncated data may bias exposure effect estimates. We analyzed the bias induced by left truncation in estimating breast cancer risk associated with exposure to airborne dioxins. Simulations were run with exposure estimates from a Geographic Information System (GIS)-based metric and considered two hypotheses for historical exposure, three scenarios for intra-individual correlation of annual exposures, and three exposure-effect models. For each correlation/model combination, 500 nested matched case-control studies were simulated and data fitted using a conditional logistic regression model. Bias magnitude was assessed by estimated odds-ratios (ORs) versus theoretical relative risks (TRRs) comparisons. With strong intra-individual correlation and continuous exposure, left truncation overestimated the Beta parameter associated with cumulative dioxin exposure. Versus a theoretical Beta of 4.17, the estimated mean Beta (5%; 95%) was 73.2 (67.7; 78.8) with left-truncated exposure and 4.37 (4.05; 4.66) with lifetime exposure. With exposure categorized in quintiles, the TRR was 2.0, the estimated OR_{Q5 vs. Q1} 2.19 (2.04; 2.33) with truncated exposure versus 2.17 (2.02; 2.32) with lifetime exposure. However, the difference in exposure between Q5 and Q1 was 18× smaller with truncated data, indicating an important overestimation of the dose effect. No intra-individual correlation resulted in effect dilution and statistical power loss. Left truncation induced substantial bias in estimating breast cancer risk associated with exposure with continuous and categorical models. With strong intra-individual exposure correlation, both models detected associations, but categorical models provided better estimates of effect trends. This calls for careful consideration of left truncation-induced bias in interpreting environmental epidemiological data.

Long-term atmospheric exposure to PCB153 and breast cancer risk in a case-control study nested in the French E3N cohort from 1990 to 2011

BACKGROUND

Although the genetic and hormonal risk factors of breast cancer are well identified, they cannot fully explain the occurrence of all cases. Epidemiological and experimental studies have suggested that exposure to environmental pollutants, especially those with potential estrogenic properties, as polychlorinated biphenyls (PCBs) may have a role in breast cancer development. Being the most abundantly detected in human tissues and in the environment, congener 153 (PCB153) is widely used in epidemiological studies as indicator for total PCBs exposure.

OBJECTIVES

We aimed to estimate the association between cumulative atmospheric exposure to PCB153 and breast cancer risk.

METHODS

We conducted a case-control study of 5222 cases and 5222 matched controls nested within the French E3N cohort from 1990 to 2011. Annual atmospheric PCB153 concentrations were simulated with the deterministic chemistry-transport model (CHIMERE) and were assigned to women using their geocoded residential history. Their cumulative PCB153 exposure was calculated for each woman from their cohort inclusion to their index date. Breast cancer odds ratios (ORs) associated with cumulative PCB153 exposure and their 95% confidence intervals (95% CIs) were estimated using multivariate conditional logistic regression models.

RESULTS

Overall, our results showed a statistically significant linear increase in breast cancer risk related to cumulative atmospheric exposure to PCB153 as a continuous variable (adjusted OR = 1.19; 95% CI: 1.08-1.31, for an increment of one standard deviation among controls (55 pg/m³)). Among women who became postmenopausal during follow-up, the association remained statistically significant (adjusted OR = 1.23; 95% CI: 1.09-1.39). In analyses by hormone receptors status, the positive association remained significant only for ER-positive breast cancer (adjusted OR = 1.18; 95% CI: 1.05-1.33).

DISCUSSION

This study is the first to have estimated the impact of atmospheric exposure to PCB153 on breast cancer risk. Our results showed a statistically significant increase in breast cancer risk, which may be limited to ER-positive breast cancer. These results warrant confirmation in further independent studies but raise the possibility that exposure to PCB153 increase breast cancer risk.

Risk of breast cancer associated with long-term exposure to benzo[a]pyrene (BaP) air pollution: Evidence from the French E3N cohort study

BACKGROUND

Benzo[a]pyrene (BaP) is an endocrine-disrupting pollutant formed during incomplete combustion of organic materials. It has been recognized as a reproductive and developmental toxicant, however epidemiological evidence of the long-term effect of ambient air BaP on breast cancer (BC) is limited. Thus we evaluated associations between ambient air BaP exposure and risk of BC, overall and according to menopausal status and molecular subtypes (estrogen receptor negative/positive (ER-/ER+) and progesterone receptor negative/positive (PR-/PR+)), stage and grade of differentiation of BC in the French E3N cohort study.

METHODS

Within a nested case-control study of 5222 incident BC cases and 5222 matched controls, annual BaP exposure was estimated using a chemistry-transport model (CHIMERE) and was assigned to the geocoded residential addresses of participants for each year during the 1990-2011 follow-up period. Multivariable conditional logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Overall, cumulative airborne BaP exposure was significantly associated with the overall risk of BC, for each 1 interquartile range (IQR) increase in the concentration levels of BaP (1.42 ng/m³), the OR = 1.15 (95% CI: 1.04-1.27). However, by menopausal status, the significant positive association remained only in women who underwent menopausal transition (i.e. premenopausal women at inclusion who became postmenopausal at diagnosis), OR per 1 IQR = 1.20 (95% CI: 1.03-1.40). By hormone receptor status, positive associations were observed for ER+, PR + and ER + PR + BC, with ORs = 1.17 (95% CI: 1.04-1.32), 1.16 (95% CI: 1.01-1.33), and 1.17 (95% CI: 1.01-1.36) per 1 IQR, respectively. There was also a borderline positive association between BaP and grade 3 BC (OR per 1 IQR = 1.15 (95% CI: 0.99-1.34).

CONCLUSIONS

We provide evidence of increased risk of BC associated with cumulative BaP exposure, which varied according to menopausal status, hormone receptor status, and grade of differentiation of BC. Our results add further epidemiological evidence to the previous experimental studies suggesting the adverse effects of BaP.

Beyond the map: evidencing the spatial dimension of health inequalities

Background

Spatial inequalities in health result from different exposures to health risk factors according to the features of geographical contexts, in terms of physical environment, social deprivation, and health care accessibility. Using a common geographical referential, which combines indices measuring these contextual features, could improve the comparability of studies and the understanding of the spatial dimension of health inequalities.

Methods

We developed the Geographical Classification for Health studies (GeoClasH) to distinguish French municipalities according to their ability to influence health outcomes. Ten contextual scores measuring physical and social environment as well as spatial accessibility of health care have been computed and combined to classify French municipalities through a K-means clustering. Age-standardized mortality rates according to the clusters of this classification have been calculated to assess its effectiveness.

Results

Significant lower mortality rates compared to the mainland France population were found in the Wealthy Metropolitan Areas (SMR = 0.868, 95% CI 0.863–0.873) and in the Residential Outskirts (SMR = 0.971, 95% CI 0.964–0.978), while significant excess mortality were found for Precarious Population Districts (SMR = 1.037, 95% CI 1.035–1.039), Agricultural and Industrial Plains (SMR = 1.066, 95% CI 1.063–1.070) and Rural Margins (SMR = 1.042, 95% CI 1.037–1.047).

Conclusions

Our results evidence the comprehensive contribution of the geographical context in the constitution of health inequalities. To our knowledge, GeoClasH is the first nationwide classification that combines social, environmental and health care access scores at the municipality scale. It can therefore be used as a proxy to assess the geographical context of the individuals in public health studies.

Chronic Low-Dose Exposure to Xenoestrogen Ambient Air Pollutants and Breast Cancer Risk: XENAIR Protocol for a Case-Control Study Nested Within the French E3N Cohort

Background

Breast cancer is the most frequent cancer in women in industrialized countries. Lifestyle and environmental factors, particularly endocrine-disrupting pollutants, have been suggested to play a role in breast cancer risk. Current epidemiological studies, although not fully consistent, suggest a positive association of breast cancer risk with exposure to several International Agency for Research on Cancer Group 1 air-pollutant carcinogens, such as particulate matter, polychlorinated biphenyls (PCB), dioxins, Benzo[a]pyrene (BaP), and cadmium. However, epidemiological studies remain scarce and inconsistent. It has been proposed that the menopausal status could modify the relationship between pollutants and breast cancer and that the association varies with hormone receptor status.

Objective

The XENAIR project will investigate the association of breast cancer risk (overall and by hormone receptor status) with chronic exposure to selected air pollutants, including particulate matter, nitrogen dioxide (NO2), ozone (O3), BaP, dioxins, PCB-153, and cadmium.

Methods

Our research is based on a case-control study nested within the French national E3N cohort of 5222 invasive breast cancer cases identified during follow-up from 1990 to 2011, and 5222 matched controls. A questionnaire was sent to all participants to collect their lifetime residential addresses and information on indoor pollution. We will assess these exposures using complementary models of land-use regression, atmospheric dispersion, and regional chemistry-transport (CHIMERE) models, via a Geographic Information System. Associations with breast cancer risk will be modeled using conditional logistic regression models. We will also study the impact of exposure on DNA methylation and interactions with genetic polymorphisms. Appropriate statistical methods, including Bayesian modeling, principal component analysis, and cluster analysis, will be used to assess the impact of multipollutant exposure. The fraction of breast cancer cases attributable to air pollution will be estimated.

Results

The XENAIR project will contribute to current knowledge on the health effects of air pollution and identify and understand environmental modifiable risk factors related to breast cancer risk.

Conclusions

The results will provide relevant evidence to governments and policy-makers to improve effective public health prevention strategies on air pollution. The XENAIR dataset can be used in future efforts to study the effects of exposure to air pollution associated with other chronic conditions.

International Registered Report Identifier (IRRID)

DERR1-10.2196/15167

Chronic long-term exposure to cadmium air pollution and breast cancer risk in the French E3N cohort

Cadmium, due to its estrogen-like activity, has been suspected to increase the risk of breast cancer; however, epidemiological studies have reported inconsistent findings. We conducted a case-control study (4,059 cases and 4,059 matched controls) nested within the E3N French cohort study to estimate the risk of breast cancer associated with long-term exposure to airborne cadmium pollution, and its effect according to molecular subtype of breast cancer (estrogen receptor negative/positive [ER-/ER+] and progesterone receptor negative/positive [PR-/PR+]). Atmospheric exposure to cadmium was assessed using a Geographic Information System-based metric, which included subject's residence-to-cadmium source distance, wind direction, exposure duration and stack height. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression. Overall, there was no significant association between cumulative dose of airborne cadmium exposure and the risk of overall, premenopausal and postmenopausal breast cancer. However, by ER and PR status, inverse associations were observed for ER- (ORQ5 vs. Q1  = 0.63; 95% CI: 0.41-0.95, ptrend  = 0.043) and for ER-/PR- breast tumors (ORQ4 vs. Q1  = 0.62; 95% CI: 0.40-0.95, ORQ5 vs. Q1  = 0.68; 95% CI: 0.42-1.07, ptrend  = 0.088). Our study provides no evidence of an association between exposure to cadmium and risk of breast cancer overall but suggests that cadmium might be related to a decreased risk of ER- and ER-/PR- breast tumors. These observations and other possible effects linked to hormone receptor status warrant further investigations.

Long-term airborne dioxin exposure and breast cancer risk in a case-control study nested within the French E3N prospective cohort

BACKGROUND

Dioxins, Group 1 carcinogens, are emitted by industrial chlorinated combustion processes and suspected to increase breast cancer risk through receptor-mediated pathways.

OBJECTIVES

We estimated breast cancer risk associated with airborne dioxin exposure, using geographic information system (GIS) methods and historical exposure data.

METHODS

We designed a case-control study (429 breast cancer cases diagnosed between 1990 and 2008, matched to 716 controls) nested within the E3N (Etude Epidémiologique auprès de femmes de la Mutuelle Générale de l'Education Nationale) cohort. Airborne dioxin exposure was assessed using a GIS-based metric including participants' residential history, technical characteristics of 222 dioxin sources, residential proximity to dioxin sources, exposure duration and wind direction. Odds ratios (OR) and 95% confidence intervals (CI) associated with quintiles of cumulative exposure were estimated using multivariate logistic regression models.

RESULTS

We observed no increased risk of breast cancer for higher dioxin exposure levels overall and according to hormone-receptor status. We however observed a statistically significant OR for Q2 versus Q1 overall (1.612, 95% CI: 1.042-2.493) and for estrogen-receptor (ER) positive breast cancer (1.843, 95% CI: 1.033-3.292).

CONCLUSIONS

Overall, as well as according to hormone-receptor status, no increased risk was observed for higher airborne dioxin exposure. The increased risk for low exposure levels might be compatible with non-monotonic dose-response relationship. Confirmation of our findings is required. Our GIS-based metric may provide an alternative in absence of ambient dioxin monitoring and may allow assessing exposure to other pollutants.

Development and performance evaluation of a GIS-based metric to assess exposure to airborne pollutant emissions from industrial sources

BACKGROUND

Dioxins are environmental and persistent organic carcinogens with endocrine disrupting properties. A positive association with several cancers, including risk of breast cancer has been suggested.

OBJECTIVES

This study aimed to develop and assess performances of an exposure metric based on a Geographic Information System (GIS) through comparison with a validated dispersion model to estimate historical industrial dioxin exposure for its use in a case-control study nested within a prospective cohort.

METHODS

Industrial dioxin sources were inventoried over the whole French territory (n > 2500) and annual average releases were estimated between 1990 and 2008. In three selected areas (rural, urban and urban-costal), dioxin dispersion was modelled using SIRANE, an urban Gaussian model and exposure of the French E3N cohort participants was estimated. The GIS-based metric was developed, calibrated and compared to SIRANE results using a set of parameters (local meteorological data, characteristics of industrial sources, e.g. emission intensity and stack height), by calculating weighted kappa statistics (wκ) and coefficient of determination (R2). Furthermore, as performance evaluation, the final GIS-based metric was tested to assess atmospheric exposure to cadmium.

RESULTS

The concordance between the GIS-based metric and the dispersion model for dioxin exposure estimate was strong (wκ median = 0.78 (1st quintile = 0.72, 3rd quintile =0.82) and R2 median = 0.82 (1st quintile = 0.71, 3rd quintile = 0.87)). We observed similar performance for cadmium.

CONCLUSIONS

Our study demonstrated the ability of the GIS-based metric to reliably characterize long-term environmental dioxin and cadmium exposures as well as the pertinence of using dispersion modelling to construct and calibrate the GIS-based metric.

Cancer incidence and mortality attributable to alcohol consumption

Alcohol consumption is a major cause of disease and death. In a previous study, we reported that in 2002, 3.6% of all cases of cancer and a similar proportion of cancer deaths were attributable to the consumption of alcohol. We aimed to update these figures to 2012 using global estimates of cancer cases and cancer deaths, data on the prevalence of drinkers from the World Health Organization (WHO) global survey on alcohol and health, and relative risks for alcohol-related neoplasms from a recent meta-analysis. Over the 10-year period considered, the total number of alcohol-attributable cancer cases increased to approximately 770,000 worldwide (5.5% of the total number of cancer cases)-540,000 men (7.2%) and 230,000 women (3.5%). Corresponding figures for cancer deaths attributable to alcohol consumption increased to approximately 480,000 (5.8% of the total number of cancer deaths) in both sexes combined-360,000 (7.8%) men and 120,000 (3.3%) women. These proportions were particularly high in the WHO Western Pacific region, the WHO European region and the WHO South-East Asia region. A high burden of cancer mortality and morbidity is attributable to alcohol, and public health measures should be adopted in order to limit excessive alcohol consumption.

Non-enzymatic antioxidant capacity and risk of gastric cancer

BACKGROUND

Consumption of fruit and vegetables has been inversely related to gastric cancer. Two studies found that dietary antioxidant capacity has some role in explaining this association. We investigated the overall antioxidant effect from diet on gastric cancer using three measures of non-enzymatic antioxidant capacity (NEAC).

METHODS

We used data from an Italian case-control study including 230 patients with incident, histologically confirmed gastric cancer, and 547 frequency matched controls admitted to the same hospitals for acute non-neoplastic diseases. A reproducible and valid food frequency questionnaire was used to assess subjects' usual diet. NEAC was measured using Italian food composition tables in terms of Trolox equivalent antioxidant capacity (TEAC), Ferric reducing-antioxidant power (FRAP) and Total radical-trapping antioxidant parameter (TRAP). We estimated the odds ratios (OR) of gastric cancer and the corresponding 95% confidence intervals (CI) using conditional logistic regression models including terms for recognized gastric cancer risk factors and total energy intake.

RESULTS

NEAC was inversely related with gastric cancer risk with ORs for the highest versus the lowest quintile of 0.54 (95%CI, 0.33-0.88) for TEAC, 0.67 (95%CI, 0.42-1.07) for FRAP and 0.57 (95%CI, 0.36-0.90) for TRAP.

CONCLUSIONS

A diet rich in antioxidant capacity reduced gastric cancer risk, suggesting a high consumption of fruit and vegetables and a moderate consumption of wine and whole cereals.

Dietary non-enzymatic antioxidant capacity and the risk of myocardial infarction: a case-control study in Italy

BACKGROUND AND AIMS

Oxidative processes have been related to atherosclerosis, but there is scanty information on the role of dietary antioxidants in the prevention of acute myocardial infarction (AMI).

METHODS AND RESULTS

The relationship between non-enzymatic antioxidant capacity (NEAC) and the risk of nonfatal AMI was investigated in a case-control study conducted in Milan, Italy, between 1995 and 2003. Cases were 760 patients below 75 years with a first episode of AMI and controls were 682 patients admitted to hospitals for acute conditions, who completed an interviewer-administered food frequency questionnaire, tested for validity and reproducibility. NEAC (excluding coffee) was measured using Italian food composition tables in terms of ferric reducing-antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) and total radical-trapping antioxidant parameter (TRAP). The odds ratios (OR) of AMI, and the corresponding 95% confidence intervals (CI), were obtained by multiple logistic regression models including terms for main risk factors of AMI and total energy intake. NEAC was inversely related with the risk of AMI. The ORs for the highest quintile compared with the lowest one were 0.41 (95% CI, 0.27-0.63) for FRAP, 0.42 (95% CI, 0.27-0.65) for TEAC and 0.41 (95% CI, 0.27-0.62) for TRAP, with significant trends in risk. The inverse relationship was apparently stronger in women and in subjects aged ≥ 60 years.

CONCLUSIONS

Our results support a favorable role of dietary NEAC in the prevention of AMI, and encourage a high consumption of fruit and vegetables and a moderate consumption of wine and whole cereals.

Glistening in glaucomatous eyes: visual performances and risk factors

PURPOSE

To analyse risk factors and visual performances of glaucomatous eyes with glistening in the intra-ocular lens (IOL).

METHODS

Prospective study performed between November 2010 and April 2011 and involving 67 consecutive glaucomatous eyes (47 patients), who previously had a phacoemulsification with a hydrophobic acrylic IOL implanted in the capsular bag. Glistening was classified in three groups of severity grade: G0 (<50 microvacuoles per mm(2) ), G1 (50-150 microvacuoles per mm(2) ), and G2 (>150 microvacuoles per mm(2) ). All eyes underwent a best-corrected visual acuity evaluation (BCVA, LogMAR scale), a complete clinical examination, a visual field test, a contrast sensitivity evaluation and a wavefront analysis of high-order aberrations (HOAs) using a Shack-Hartmann aberrometer. Eyes with a posterior capsular opacification and a BCVA>0.30 LogMAR were excluded.

RESULTS

Twenty six eyes (38.8%) had a grade 0, 12 eyes (17.9%) a grade 1 and 29 eyes (43.3%) a grade 2 of glistening severity grade. The mean follow-up after cataract surgery was 35.2 ± 24.2 months and was significantly higher for G1 and G2 groups (p < 0.001). A higher number of topical glaucoma medication were associated with a higher glistening severity grade (p < 0.05). G1 and G2 groups had significantly lower mean contrast sensitivity values at high spatial frequencies and significantly higher loss variance (LV) values of the visual field test (p < 0.05). There was no significant difference in mean BCVA between groups (p = 0.455).

CONCLUSIONS

In glaucomatous eyes, glistening increased with time was associated with the number of topical glaucoma medications daily instilled and altered visual performances. It should be a consideration for glaucoma patients who are more likely to develop glistening within the IOL optic.

Adherence to the Mediterranean diet and gastric cancer risk in Italy

We investigated gastric cancer risk in relation to the adherence to the Mediterranean diet using data from two case-control studies conducted in Italy between 1985 and 2007, including 999 incidents, histologically confirmed gastric cancers and 2,628 controls admitted to hospital for acute non-neoplastic diseases. Adherence to the Mediterranean diet was assessed using the Mediterranean Diet Score (MDS) based on nine of the major characteristics of the Mediterranean diet in the overall dataset. The Mediterranean Dietary Pattern adherence index (MDP) and the Mediterranean Adequacy Index (MAI) were considered in the second study only. We estimated odds ratios (OR) and corresponding 95% confidence intervals (CI) of gastric cancer for categories of the three scores using multiple logistic regression models. We found a reduced risk of gastric cancer for increasing levels of the MDS: as compared to subjects in the lowest category of the MDS, the ORs were 0.78, 0.61 and 0.57 in subsequent levels of MDS, with a significant trend in risk. Risk estimates were consistent across strata of age, sex, education, smoking, body mass index, and family history of gastric cancer. We also observed a decreased risk of gastric cancer for the highest versus the lowest quintile for MDP and MAI, with OR of 0.58 and 0.71, respectively. Our study provides convincing evidence of a beneficial role of the Mediterranean diet on gastric cancer.

Corneal confocal microscopy following conventional, transepithelial, and accelerated corneal collagen cross-linking procedures for keratoconus

PURPOSE

To compare early corneal healing following conventional, transepithelial, and accelerated corneal collagen cross-linking (CXL) protocols.

METHODS

Twenty-four patients with progressive keratoconus were divided into three groups to receive conventional, transepithelial, or accelerated CXL. In vivo corneal confocal microscopy was performed on each patient preoperatively and at 1, 3, and 6 months postoperatively.

RESULTS

Closure of the epithelial wound was complete 3 days following conventional and accelerated CXL. The subbasal nerve plexus was essentially obliterated immediately following conventional and accelerated CXL, and virtually no nerve fibers had regenerated by 6 months. The anterior stroma showed significant changes 1 month following conventional CXL; these changes were similar but more pronounced following accelerated CXL. Observed stromal changes included complete obliteration of keratocytes, increased tissue reflectivity, a honeycomb-like appearance, and circular lacunae. Some recovery of keratocyte density was noted after 6 months. These changes were less pronounced in the mid-stroma, and there were no apparent changes to the posterior stroma or endothelium. The cornea appeared to be unaltered following transepithelial CXL.

CONCLUSIONS

In vivo corneal confocal microscopy analysis of the postoperative impact of CXL on the cornea revealed clear differences among conventional, accelerated, and transepithelial CXL protocols. Accelerated CXL had a greater impact than conventional CXL on the anterior cornea, whereas transepithelial CXL did not appear to alter corneal morphology.

Incidence of glistenings with the latest generation of yellow-tinted hydrophobic acrylic intraocular lenses

PURPOSE

To evaluate the incidence of glistenings in a large series of consecutive eyes with a blue light-filtering hydrophobic acrylic intraocular lens (IOL) and the relationship with parameters such as age, sex, follow-up length, and corrected distance visual acuity (CDVA).

SETTING

Service d'Ophtalmologie, Centre Hospitalier et Universitaire Bordeaux, Bordeaux, France.

DESIGN

Cross-sectional study.

METHODS

This study included 111 eyes of 74 patients (age range 33 to 86 years). All cases had cataract surgery with Acrysof SN60WF monofocal IOL implantation and had a routine postoperative examination between March 2011 and June 2011. The incidence and severity of glistenings were evaluated with the slitlamp. Also evaluated was their relationship with age, sex, follow-up length, IOL power, and CDVA. Glistenings were subjectively graded (0 = absent; 1 = moderate; 2 = dense).

RESULTS

Glistenings occurred in 96 eyes (86.5%). Glistenings were of grade 1 severity in 45 eyes (40.5%) and of grade 2 severity in 51 eyes (45.9%). The follow-up was significantly longer in eyes with grade 2 glistenings (P ≤ .01). A limited, but significant, correlation was found between glistening severity and length of follow-up (r = 0.32, P<.01). Although there was a trend toward decreased visual acuities at higher glistening grades (r = 0.22, P = .01), there were no significant differences in CDVA between the glistening severity groups (P = .14).

CONCLUSIONS

Glistenings were common in eyes with the blue light-filtering hydrophobic acrylic IOL and increased over time.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Scalability and severity of keratoconus in children

PURPOSE

To assess the severity of keratoconus at diagnosis and its scalability over a period of 2 years in children compared to adults.

DESIGN

A retrospective monocentric study was conducted in the National Reference Center for Keratoconus, Bordeaux (France), between October 1997 and November 2010.

METHODS

In total, 216 patients were studied, comprising 49 patients (22.7%) aged ≤ 15 and 167 patients (77.3%) aged ≥ 27 years at diagnosis, who were seen within 2 years of diagnosis. Severity at diagnosis was assessed using Krumeich's classification, and the scalability criteria of the US Food and Drug Administration (2010) were used. Student t tests and χ(2) tests were performed to compare the 2 groups.

RESULTS

Keratoconus in children was significantly more severe at diagnosis, with 27.8% being stage 4 vs 7.8% of adults (P < .0001). In addition, ophthalmoscopic signs were more frequent in children (42.9% vs 29.5%, P = .05), while mean values of maximum, average, and minimum keratometry as well as simulated keratometric astigmatism were higher (P < .0001, P = .0002, P = .0005, and P = .001, respectively). After diagnosis, keratoconus did not evolve more frequently in children. However, in the case of progression, keratoconus evolved faster in children, with significant differences in the spherical equivalent and maximum and minimum keratometry (P = .03, P = .02, P = .04, respectively).

CONCLUSION

At diagnosis, keratoconus is often more advanced in children than in adults, with faster disease progression. Early detection and close monitoring are therefore crucial in young patients.

Recent patterns in gastric cancer: a global overview

Until the mid-1990s, gastric cancer has been the first cause of cancer death worldwide, although rates had been declining for several decades and gastric cancer has become a relatively rare cancer in North America and in most Northern and Western Europe, but not in Eastern Europe, Russia and selected areas of Central and South America or East Asia. We analyzed gastric cancer mortality in Europe and other areas of the world from 1980 to 2005 using joinpoint regression analysis, and provided updated site-specific incidence rates from 51 selected registries. Over the last decade, the annual percent change (APC) in mortality rate was around -3, -4% for the major European countries. The APC were similar for the Republic of Korea (APC = -4.3%), Australia (-3.7%), the USA (-3.6%), Japan (-3.5%), Ukraine (-3%) and the Russian Federation (-2.8%). In Latin America, the decline was less marked, but constant with APC around -1.6% in Chile and Brazil, -2.3% in Argentina and Mexico and -2.6% in Colombia. Cancers in the fundus and pylorus are more common in high incidence and mortality areas and have been declining more than cardia gastric cancer. Steady downward trends persist in gastric cancer mortality worldwide even in middle aged population, and hence further appreciable declines are likely in the near future.

Dietary glycemic load and gastric cancer risk in Italy

We investigated gastric cancer risk in relation to dietary glycemic index (GI) and glycemic load (GL), which represent indirect measures of carbohydrate absorption and consequently of dietary insulin demand, in a case-control study conducted in northern Italy between 1997 and 2007, including 230 patients with the incident, histologically confirmed gastric cancer and 547 frequency matched controls, admitted to the same hospitals as cases with acute non-neoplastic conditions. We used conditional logistic regression models, including terms for major recognised gastric cancer risk factors and non-carbohydrate energy intake. The odds ratios (ORs) in the highest vs lowest quintile were 1.9 (95% CI: 1.0–3.3) for GI and 2.5 (95% CI: 1.3–4.9) for GL. Compared with participants reporting low GL and high fruits/vegetables intake, the OR rose across strata of high GL and low fruits/vegetables, to reach 5.0 (95% CI: 2.2–11.5) for those reporting low fruits/vegetables intake and high GL. Our study may help to explain the direct relation observed in several studies between starchy foods and gastric cancer risk.