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A comparison of meta-analysis results with and without adjustment for the healthy worker effect: cancer mortality among workers in the semiconductor industry

Authors :
Sung-Ho Hwang
Moon-Young Park
Won Jin Lee
Inho Park
Kimyong Hong
Donguk Park
Kyoung-Mu Lee
Source :
Epidemiology and Health, Vol 43 (2021)
Publication Year :
2021
Publisher :
Korean Society of Epidemiology, 2021.

Abstract

OBJECTIVES This study compared the results of meta-analysis with and without adjustment for the healthy worker effect on the association between working in the semiconductor industry and cancer mortality. METHODS Six studies that reported standardized mortality ratios (SMRs) for cancers were selected for meta-analysis. Using a random-effects model, the SMR results from each study were combined for all cancers and leukemias to estimate the summary SMRs (95% confidence interval, CI). To adjust for the healthy worker effect, the relative standardized mortality ratio (rSMR=SMRx/SMRnot x) were calculated using observed and expected counts for the specific cause of interest (i.e., all cancers and leukemias) and the observed and expected counts for all other causes of mortality. Then, the rSMR results were combined to estimate the summary rSMRs (95% CIs). RESULTS The SMRs for all causes of mortality among semiconductor industry workers ranged from 0.25 to 0.80, which reflects a significant healthy worker effect. A remarkable difference was found between the summary SMRs and the summary rSMRs. The summary SMR for all cancers was 0.70 (95% CI, 0.63 to 0.79) whereas the summary rSMR was 1.38 (95% CI, 1.20 to 1.59). The summary SMR for leukemia was 0.88 (95% CI, 0.72 to 1.07), and the summary rSMR was 1.88 (95% CI, 1.20 to 2.95). CONCLUSIONS Our results suggest that adjustment for the healthy worker effect (i.e., rSMR) may be useful in meta-analyses of cohort studies reporting SMRs.

Details

Language :
English
ISSN :
20927193
Volume :
43
Database :
Directory of Open Access Journals
Journal :
Epidemiology and Health
Publication Type :
Academic Journal
Accession number :
edsdoj.faafa604940768e38d7ab5f3b76e8
Document Type :
article
Full Text :
https://doi.org/10.4178/epih.e2021057