Manuel R. Gómez

Effects of three features of a job-exposure matrix on risk estimates.

We tested the impact of three features of a job-exposure matrix on risk estimates in a case-control study that evaluated the association of methylene chloride and astrocytic brain cancer. These features were probability of use of the agent; the consideration of decade of predominant use of methylene chloride within each occupation; and the use of a more specific industrial-occupational coding system. We compared the risk estimates obtained with and without these features. The introduction of each feature had a striking effect on the estimate of relative risk. The odds ratio ranged from 1.47 with none of these features, to 2.47 with high probability of exposure within industry and occupation, to 4.15 with high probability of exposure and specific industrial-occupational coding, to 6.08 with the three features together. These results indicate that the degree of exposure misclassification can be reduced by the introduction of these features into the job-exposure matrix.

A Proposal to Develop a National Occupational Exposure Databank

Abstract The rationale and strategy to develop a national occupational exposure databank (NOED) are described. The NOED would support exposure assessment activities that are needed to accomplish risk assessment and risk management goals, including exposure assessment research, epidemiologic investigations, surveillance, and policy and program design and evaluation. By defining exposures and the parameters associated with them in various industries and jobs, the NOED would also focus increased attention on the need to reduce occupational health hazards. The proposed NOED would contain exposure measurements and information about exposure determinants, and it would rely initially on data from compliance-related activities in the federal sector. The criteria needed for an effective databank are discussed, along with the need to improve the methods now available to capture and code exposure determinants. Two steps to develop the NOED are proposed for immediate adoption: (1) the creation of an initial database ...

Factors Associated with Exposure in Occupational Safety and Health Administration Data

This study investigated the possibility of making compliance data from the public and private sectors more amenable for multiple uses, by studying data from Occupational Safety and Health Administration (OSHA) inspections during 1979-1989. The potential association of five variables with mean and upper-end (in upper quartile) airborne exposures in similar exposure groups was investigated. The exposure groups reflected airborne exposures to lead in the battery manufacturing industry, to perchloroethylene among dry cleaners, and to iron oxide among welders in three metal fabrication industries. Variables examined were year, inspection type and scope, and size and union status of inspected establishments. Multiple linear regression and logistic regression models were used for the analyses. In small battery plants mean exposure levels were higher and the relative frequency of upper-end exposures (> 75th percentile) greater than in larger establishments. Evidence suggested a decline in mean lead exposures (5-9% per year). Neither type of inspection nor union status were associated with mean or upper-end levels of lead exposure, although the studys power to detect an association was sometimes modest. Some evidence showed that full scope inspections may be associated with higher mean exposures. Strong evidence showed a decline in mean perchloroethylene exposures among dry cleaners (7% per year), but no temporal trends for welder exposures to iron oxide. With few exceptions, the size, type, scope, and union variables were rarely associated with mean or upper-end exposure levels among dry cleaners or welders, although the power of the analyses to detect associations was at times modest. Results show that OSHA data is amenable to analysis that can provide valuable insights about workplace exposures. Several findings of the study are directly useful to the design of public policy.

Conference on Occupational Exposure Databases: A Report and Look at the Future

Abstract The rationale, goals, and interdisciplinary and multi-institutional character of the Conference on Occupational Exposure Databases are described based on a conceptual framework for thinking about exposure data. The three areas that pose the critical challenges to database developments are discussed: 1) the multiple and changing uses and users of data; 2) the need for better and standardized definitions of the exposure-relevant information which should be collected along with exposure measurements; and 3) the closely related and equally critical coding issues. The concluding section summarizes the principal consensus views and recommendations from the conference and the status of the activities now underway to implement those recommendations. Gomez, M.R.; Rawls, G.: Conference on Occupational Exposure Databases: A Report and Look at the Future. Appl. Occup. Environ. Hyg. 10(4):238–243; 1995.

Collection of Exposure Data for Retrospective Occupational Epidemiologic Studies

Abstract Performing an exposure assessment in occupational epidemiology studies requires the collection of a wide variety of exposure data, because there are usually too few biological or air monitoring measurements over the time period of interest to allow retrospective assessment of exposures for individual study subjects. This article describes different types of exposure data that can be used to supplement monitoring results and provides a brief description of how they might be used. It also identifies sources from which these data may be obtained and the resources that may be needed to collect them.

Exposure Assessment for a Study of Workers Exposed to Acrylonitrile. I. Job Exposure Profiles: A Computerized Data Management System

Procedures used to develop estimates of exposure to acrylonitrile for a cohort study (>25000 workers in 8 monomer, fiber, and resin companies from 1952 to 1983) are presented. Visits to the companies were made, interviews of workers were conducted, historical records were made, and measurements were taken. On the basis of similar tasks, locations, other exposures, and a similar distribution of exposures to acrylonitrile, 3600 exposure groups were formed. Special procedures were used to reduce the misclassification of workers performing tasks that varied in time but that were inadequately reflected in the job title. A software program organized and retained all exposure information on each exposure group. Quantitative estimates of acrylonitrile exposure were developed using a hierarchical approach in a software program that documented the derivation of each estimate and facilitated data review. Two of the estimation methods were evaluated in a comparison with measurement data.

Risk Assessment for Carcinogens: A Comparison of Approaches of the ACGIH and the EPA

Abstract The relative carcinogenic potency of 16 chemicals evaluated by both the U.S. Environmental Protection Agency (EPA) and the Chemical Substances Threshold Limit Values (CS-TLV) Committee of the American Conference of Governmental Industrial Hygienists (ACGIH) were compared. The estimated cancer risk resulting from occupational exposure to the threshold limit values (TLVs) were also computed using dose-response curves developed as a part of EPA quantitative risk assessments. Substantial agreement between the EPA and the CS-TLV Committee was found when the relative potency of these carcinogens was compared. Use of EPAs risk model to estimate lifetime cancer risk from occupational exposure at the TLV levels often resulted in high cancer risk estimates. The approaches used to assess cancer risk by both groups is described and a suggestion is made for incorporating existing quantitative risk assessments into the TLV evaluation procedure.

Exposure assessment must stop being local.

Exposure assessment activities today are hampered by a narrow focus that is detrimental to preventive occupational health goals. Exposure data useful for disease prevention are not adequately collected, and exposure surveillance tools do not receive adequate attention. Professional recommendations to improve this state of affairs have been in existence since the early 1990s, but have not been widely adopted. Although the Government Performance and Results Act could help address these shortcomings--by enhancing exposure surveillance activities in the OSHA and NIOSH Strategic Plans--the agencies have not taken advantage of this opportunity. Their strategic plans rely largely on accident data to measure performance, despite the fact that occupational disease has a much larger toll. This article makes recommendations to address these shortcomings by increasing the role of exposure surveillance tools in the agency strategic plans.

Recommendations for methods to code industry and job task in routinely collected exposure data

This article describes and recommends two coding methods that can improve the capture of exposure-relevant information in large occupational exposure databases. One of the methods can substantially improve the specificity of information captured by industry codes, and the second would improve the capture of information about job tasks in a standardized fashion, a capability almost entirely lacking in occupational health. The methods are not ideally designed for exposure assessment purposes, but their use would represent a substantial improvement over current practices. The methods have been well tested and can be adopted in their current form. Moreover, they are compatible with coding systems already in widespread use for economic, demographic, health, and other data, thus making exposure data coded with them amenable to valuable linkages. Large collections of routine exposure measurements are increasingly common, and the use of these coding methods will help improve the needed coding of precise informati...

Methylene chloride and brain cancer: Interpreting a new study in light of existing literature

(This article is a US Government work and, as such, is in the public domain in the United States of America.)