Job-exposure matrix for the assessment of alkylphenolic compounds

Occupational exposure to pesticides and endometrial cancer in the Screenwide case-control study

BACKGROUND

Endometrial cancer is the most common gynaecological tumour in developed countries and disease burden is expected to increase over the years. Identifying modifiable risk factors may help developing strategies to reduce the expected increasing incidence of these neoplasms.

OBJECTIVE

This study evaluates the association between occupational exposure to pesticides and endometrial cancer using data from a recent case-control study in Spain.

METHODS

The analyses included data from 174 consecutive incident endometrial cancer cases and 216 hospital controls frequency-matched by age. Data were collected through structured epidemiological questionnaires and exposure to pesticides was assessed using a Spanish job-exposure matrix (MatEmESp).

RESULTS

Overall, 12% of controls and 18% of cases were occupationally exposed to pesticides. We observed a positive association between occupational exposure to pesticides and endometrial cancer (OR = 2.08; 95% CI = 1.13-3.88 compared to non-exposed). In general, exposures that occurred farther in the past were significantly associated with endometrial cancer. Exposure to insecticides, fungicides and herbicides were positively associated with endometrial cancer (OR = 2.08; 95% CI = 1.13-3.88, OR = 4.40; 95% CI = 1.65-13.33, and OR = 5.25; 95% CI = 1.84-17.67, respectively). The agricultural, poultry and livestock activities scenario was associated with endometrial cancer (OR = 4.16; 95% CI = 1.59-12.32), while the cleaning exposure scenario was not (OR = 1.22; 95% CI = 0.55-2.67).

CONCLUSIONS

Assessment of occupational exposure to pesticides assessed using a Spanish job-exposure matrix revealed a positive association with endometrial cancer. The elucidation of the role of pesticide compounds on endometrial cancer should shed a light on the aetiology of this tumour.

Endocrine disruptors: Challenges and future directions in epidemiologic research

Public concern about the impact of endocrine disrupting chemicals (EDCs) on both humans and the environment is growing steadily. Epidemiologic research provides key information towards our understanding of the relationship between environmental exposures like EDCs and human health outcomes. Intended for researchers in disciplines complementary to epidemiology, this paper highlights the importance and challenges of epidemiologic research in order to present the key elements pertaining to the design and interpretation of an epidemiologic study on EDCs. The conduct of observational studies on EDCs derives from a thoughtful research question, which will help determine the subsequent methodological choices surrounding the careful selection of the study population (including the comparison group), the adequate ascertainment of exposure(s) and outcome(s) of interest, and the application of methodological and statistical concepts more specific to epidemiology. The interpretation of epidemiologic results may be arduous due to the latency occurring between EDC exposure and certain outcome(s), the complexity in capturing EDC exposure(s), and traditional methodological and statistical issues that also deserve consideration (e.g., confounding, effect modification, non-monotonic responses). Moving forward, we strongly advocate for an integrative approach of expertise in the fields of epidemiology, exposure science, risk assessment and toxicology to adequately study the health risks associated with EDCs while tackling their challenges.

Impact of Variability in Job Coding on Reliability in Exposure Estimates Obtained via a Job-Exposure Matrix

OBJECTIVES

The use of a job-exposure matrix (JEM) to assess exposure to potential health hazards in occupational epidemiological studies requires coding each participant's job history to a standard occupation and/or industry classification system recognized by the JEM. The objectives of this study were to assess the impact of inter-coder variability in job coding on reliability in exposure estimates derived from linking the job codes to the Canadian job-exposure matrix (CANJEM) and to identify influent parameters.

METHOD

Two trained coders independently coded 1000 jobs sampled from a population-based case-control study to the ISCO-1968 occupation classification at the five-digit resolution level, of which 859 could be linked to CANJEM using both assigned codes. Each of the two sets of codes was separately linked to CANJEM and thereby generated, for each of the 258 occupational agents available in CANJEM, two exposure estimates: exposure status (yes/no) and intensity of exposure (low, medium, and high) for exposed jobs only. Then, inter-rater reliability (IRR) was computed (i) after stratifying agents in 4 classes depending, for each, on the proportion of occupation codes in CANJEM defined as 'exposed' and (ii) for two additional scenarios restricted to jobs coded differently: the first one using experts' codes, the other one using codes randomly selected. IRR was computed using Cohen's kappa, PABAK and Gwet's AC1 index for exposure status, and weighted kappa and Gwet's AC2 for exposure intensity.

RESULTS

Across all agents and based on all jobs, median (Q1, Q3; Nagents) values were 0.68 (0.59, 0.75; 220) for kappa, 0.99 (0.95, 1.00; 258) for PABAK, and 0.99 (0.97, 1.00; 258) for AC1. For the additional scenarios, median kappa was 0.28 (0.00, 0.45; 209) and -0.01 (-0.02, 00; 233) restricted to jobs coded differently using experts' and random codes, respectively. A similar decreasing pattern was observed for PABAK and AC1 albeit with higher absolute values. Median kappa remained stable across exposure prevalence classes but was more variable for low prevalent agents. PABAK and AC1 decreased with increasing prevalence. Considering exposure intensity and all exposed jobs, median values were 0.79 (0.68, 0.91; 96) for weighted kappa, and 0.95 (0.89, 0.99; 102) for AC2. For the additional scenarios, median kappa was, respectively, 0.28 (-0.04, 0.42) and -0.05 (-0.18, 0.09) restricted to jobs coded differently using experts' and random codes, with a similar though attenuated pattern for AC2.

CONCLUSION

Despite reassuring overall reliability results, our study clearly demonstrated the loss of information associated with jobs coded differently. Especially, in cases of low exposure prevalence, efforts should be made to reliably code potentially exposed jobs.

Alkylphenolic compounds and risk of breast and prostate cancer in the MCC-Spain study

BACKGROUND

Alkylphenolic compounds are chemicals with endocrine disrupting properties that have been widely used in industry with important changes in their usage over time. Few epidemiologic studies have evaluated the effect of alkylphenolic compounds on human health.

OBJECTIVES

We investigated whether occupational exposure to alkylphenolic compounds is associated with breast and prostate cancer.

METHODS

We carried out a population-based case-control study including 1513 incident cases of breast cancer, 1095 of prostate cancer, and 3055 controls, frequency matched by sex, age and region. Occupational exposure to alkylphenolic compounds was estimated using a recently developed job-exposure matrix, which considered different scenarios of exposure and different subtypes of alkylphenolic compounds.

RESULTS

History of occupational exposure to alkylphenolic compounds was modestly associated with breast cancer (OR = 1.23; 95% CI = 1.01-1.48). Within the different scenarios, the occupational use of domestic tensioactives was positively associated with breast cancer (OR = 1.28; 95% CI = 1.02-1.60), while occupational exposure in other scenarios showed mostly a suggestion of a similar positive associations. Exposure to nonylphenol ethoxylates was positively associated with breast cancer (OR = 1.21; 95% CI = 1.00-1.47), while exposure to other compounds was uncommon. In general, we did not observe associations between alkylphenolic compounds and prostate cancer, except for a positive association among men occupationally exposed to cosmetic, hair and personal hygiene products.

CONCLUSIONS

Our findings suggest a modest association between breast cancer risk and occupational exposure to alkylphenolic compounds, and no associations between these compounds and prostate cancer risk. These findings warrant further corroboration in other studies.

Update of an occupational asthma-specific job exposure matrix to assess exposure to 30 specific agents

OBJECTIVES

We aimed to update an asthmagen job exposure matrix (JEM) developed in the late 1990s. Main reasons were: the number of suspected and recognised asthmagens has since tripled; understanding of the aetiological role of irritants in asthma and methodological insights in application of JEMs have emerged in the period.

METHODS

For each agent of the new occupational asthma-specific JEM (OAsJEM), a working group of three experts out of eight evaluated exposure for each International Standard Classification of Occupations, 1988 (ISCO-88) job code into three categories: 'high' (high probability of exposure and moderate-to-high intensity), 'medium' (low-to-moderate probability or low intensity) and 'unexposed'. Within a working group, experts evaluated exposures independently from each other. If expert assessments were inconsistent the final decision was taken by consensus. Specificity was favoured over sensitivity, that is, jobs were classified with high exposure only if the probability of exposure was high and the intensity moderate-to-high. In the final review, all experts checked assigned exposures and proposed/improved recommendations for expert re-evaluation after default application of the JEM.

RESULTS

The OAsJEM covers exposures to 30 sensitisers/irritants, including 12 newly recognised, classified into seven broad groups. Initial agreement between the three experts was mostly fair to moderate (κ values 0.2-0.5). Out of 506 ISCO-88 codes, the majority was classified as unexposed (from 82.6% (organic solvents) to 99.8% (persulfates)) and a minority as 'high-exposed' (0.2% (persulfates) to 2.6% (organic solvents)).

CONCLUSIONS

The OAsJEM developed to improve occupational exposure assessment may improve evaluations of associations with asthma in epidemiological studies and contribute to assessment of the burden of work-related asthma.