TY - JOUR
T1 - A comparison of meta-Analysis results with and without adjustment for the healthy worker effect
T2 - Cancer mortality among workers in the semiconductor industry
AU - Hwang, Sung Ho
AU - Park, Moon Young
AU - Lee, Won Jin
AU - Park, Inho
AU - Hong, Kimyong
AU - Park, Donguk
AU - Lee, Kyoung Mu
N1 - Publisher Copyright:
© 2021 Korean Society of Epidemiology. All Rights Reserved.
PY - 2021
Y1 - 2021
N2 - 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.
AB - 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.
KW - Healthy worker effect
KW - Meta-Analysis
KW - Mortality
KW - Semiconductor
UR - http://www.scopus.com/inward/record.url?scp=85122166511&partnerID=8YFLogxK
U2 - 10.4178/epih.e2021057
DO - 10.4178/epih.e2021057
M3 - Article
C2 - 34525505
AN - SCOPUS:85122166511
SN - 2092-7193
VL - 43
JO - Epidemiology and health
JF - Epidemiology and health
M1 - e2021057
ER -