Component Associations of the Healthy Worker Survivor Bias in Medical Radiation Workers

Abstract

Background

The healthy worker survivor bias may vary by sex. This study investigated three component associations necessary for this bias to determine the origins of sex differences in this bias among male and female workers.

Methods

We analyzed a data set of 93,918 South Korean diagnostic medical radiation workers registered in the National Dose Registry from 1996 to 2011, linked with mortality and cancer incidence data. Component associations were assessed using Cox regression to estimate hazard ratios (HRs) and logistic regression with generalized estimating equations to estimate odds ratios (ORs).

Results

A significant association between prior cumulative exposure and employment status was observed for all-cause mortality in male (HR 1.06, 95% CI 1.02–1.10), whereas an inverse association was noted in female workers (HR 0.82, 95% CI 0.78–0.87). Adjusted ORs for employment status and subsequent exposure for all-cause mortality, as well as HRs for employment status and survival time, demonstrated associations in the same direction in both males and females.

Conclusions

Our findings demonstrate that sex-specific differences in healthy worker survivor bias were primarily driven by the association between prior exposure and employment status. To improve bias mitigation in occupational cohort studies, sex-specific components should be incorporated.