Healthy worker effect on Japanese industry workers: a commentary from the viewpoint of industrial health management

Abstract

Healthy worker effect (HWE), which can be described as a lower death rate within a work force when compared to the general population, has been observed in many epidemiological mortality studies on industrial work populations free of significant life-shortening hazards. The purpose of this report is to evaluate this effect on the active work populations engaged in large scale manufacturing companies in Japan, and to appreciate the possible attributable factors to this phenomenon. Standardized mortality ratios (SMRs) were calculated for workers in the member companies of The Japan Iron and Steel Federation (JISF) and The Japan Chemical Fibers and Textile Association (JCFTA), where mortality surveillance systems have been established. SMRs for all causes of death from 1969 to 1981 were within the range of 50 to 81 in JISF, and 34 to 41 in JCFTA. These results point to the existence of strong HWE, equal to or even lower than the reported values in some industrial populations in the United States. An evident HWE for cancer was also observed in the study populations, but it was reported to be of little significance, if at all, in the United States. HWE can be considered as a composite result of factors such as: (1) selection of healthier work force, (2) risk reduction due to life style modification during employment, and (3) methodological characteristics of the SMR, which are dependent on the percentage of active workers.(ABSTRACT TRUNCATED AT 250 WORDS)