Characteristics of worker populations: exposure considerations in the selection of study populations and their analysis.
Park-RM; Silverstein-MA; Mirer-FE
Appl Occup Environ Hyg 1991 Jun; 6(6):436-440
A discussion was presented of worker population characteristics in terms of exposure considerations for selection and analysis of study populations. For many chemical exposures, end use populations rather than production populations received highest exposures. End use groups could be diverse and wide spread and their exposures might be complex, requiring innovative industrial hygiene approaches for characterization. Because population based studies identified disease cases from a general population rather than a specific group, exposure misclassification could occur due to inconsistent terminology or variability in worker awareness. Problems associated with data on workers with accessible exposure histories were noted. A system was presented which used a group of eight to 20 employees from a single facility, representing hourly and salaried employees with long employment histories at the facility. Management and production and maintenance personnel were included. Investigators would meet with this group to obtain consensus information on exposures and industrial conditions and processes. Employment selection considerations were discussed. The healthy worker effect was noted for cardiovascular, respiratory and malignancy effects. In a study comparing standardized mortality ratios (SMRs) with relative SMRs (a proportional mortality ratio surrogate), it was noted that relative SMRs generally provided better estimates of work related mortality in aggregate populations. Internal exposure comparisons were important when SMRs were used. Social class effects were noted. Paradoxical dose responses were discussed, and inconsistent exposure level over duration of exposure or employment was addressed. Shortening of employment due to high exposures was considered, and a theoretical model of exposure driven employment duration was presented. The authors recommend interpreting statistically significant paradoxical dose responses as evidence of exposure related health effects.
NIOSH-Publication; NIOSH-Contract; Contract-91-38661; Humans; Occupational-exposure; Analytical-methods; Risk-analysis; Analytical-models; Epidemiology; Exposure-levels; Employee-health; Mortality-data
Applied Occupational and Environmental Hygiene