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Kyoung-Mu Lee 2 Articles
A comparison of meta-analysis results with and without adjustment for the healthy worker effect: cancer mortality among workers in the semiconductor industry
Sung-Ho Hwang, Moon-Young Park, Won Jin Lee, Inho Park, Kimyong Hong, Donguk Park, Kyoung-Mu Lee
Epidemiol Health. 2021;43:e2021057.   Published online September 8, 2021
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  • 159 Download
  • 1 Citations
AbstractAbstract AbstractSummary PDF
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.
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).
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).
Our results suggest that adjustment for the healthy worker effect (i.e., rSMR) may be useful in meta-analyses of cohort studies reporting SMRs.
Korean summary
본 연구에서는 반도체 근로자의 암사망률을 일반 인구와 비교하여 표준화사망비(SMR)를 제시한 연구를 대상으로 한 메타분석에서, summary SMR값(95% CI)과 건강근로자효과에 대해 보정한 rSMR을 산출한 후 종합한 summary rSMR값(95% CI)을 비교하였다. 모든 암의 경우 summary SMR=0.70 (0.63-0.79), summary rSMR=1.38(1.20-1.59)로 나타났으며, 백혈병의 경우 summary SMR=0.88 (0.72-1.07), summary rSMR=1.88(1.20-2.95)로 나타났다. 본 연구결과는 SMR 연구를 종합하는 메타분석 연구에서 rSMR과 같은 건강근로자효과에 대해 보정하는 방법론을 적용할 수 있음을 보여주는 사례이다.
Key Message
The relevance of epidemiological research reporting the standardized mortality ratios (SMRs) for workers in the semiconductor industry is often limited by the healthy worker effect. One of the simple correction methods in the relative standardized mortality ratio (rSMR). We observed significant rightward shift when the summary rSMRs were compared with the summary rSMRs, which suggest that adjustment for the healthy worker effect (i.e., rSMR) may be useful in meta-analyses of cohort studies reporting SMRs.


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    Turid Austin Wæhler, Tor Ingebrigtsen
    International Journal of Circumpolar Health.2022;[Epub]     CrossRef
No Association Between Functional Polymorphisms in COMT and MTHFR and Schizophrenia Risk in Korean Population
Ho Jin Kang, Byeong Moo Choe, Seong Hwan Kim, Seung-Rak Son, Kyoung-Mu Lee, Byoung Gwon Kim, Young-Seoub Hong
Epidemiol Health. 2010;32:e2010011.   Published online December 24, 2010
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  • 126 Download
  • 12 Citations
AbstractAbstract PDF

Common genetic SNPs in two genes, encoding catechol-O-methyltransferase (COMT) and methylenetetrahydrofolate reductase (MTHFR), which are interconnected with COMT gene regulation, have been reported to contribute to schizophrenia risk. In this study, we evaluated the association between functional polymorphisms in COMT and MTHFR and schizophrenia risk with a case-control study in a Korean population.


We performed a case-control study by genotyping analysis using 360 cases and 348 controls in Korean subjects to determine the association between functional polymorphisms in COMT and MTHFR and schizophrenia risk.


Four functional SNPs in COMT (Val158Met and rs165599) and MTHFR (C677T and A1298C) were genotyped by primer extension assay. None of the genotype distributions for the four SNPs was significantly different between cases and controls. Stratified analysis did not show any significant gender difference for any polymorphism. In addition, we found no evidence of a gene-gene interaction in the analysis of combined genotypes.


Our results suggest no significant association between the selected functional polymorphisms of COMT or MTHFR in Korean schizophrenia subjects. However, further studies are required to confirm our findings in a larger number of subjects.

Korean summary
Key Message


Citations to this article as recorded by  
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    Xinyao Meng, Ji-long Zheng, Mao-ling Sun, Hai-yun Lai, Bao-jie Wang, Jun Yao, Hongbo Wang, Zezhi Li
    PLOS ONE.2022; 17(7): e0271170.     CrossRef
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    Frontiers in Psychiatry.2022;[Epub]     CrossRef
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    Psychiatric Genetics.2018; 28(6): 110.     CrossRef
  • Role of MTHFR C677T gene polymorphism in the susceptibility of schizophrenia: An updated meta-analysis
    Upendra Yadav, Pradeep Kumar, Sanjay Gupta, Vandana Rai
    Asian Journal of Psychiatry.2016; 20: 41.     CrossRef
  • The Role of a Catechol-O-Methyltransferase (COMT) Val158Met Genetic Polymorphism in Schizophrenia: A Systematic Review and Updated Meta-analysis on 32,816 Subjects
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    NeuroMolecular Medicine.2016; 18(2): 216.     CrossRef
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    Shusuke Numata, Makoto Kinoshita, Atsushi Tajima, Akira Nishi, Issei Imoto, Tetsuro Ohmori
    BMC Medical Genetics.2015;[Epub]     CrossRef
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    Su-Gyeong Kim, Joo Yun Song, Eun-Jeong Joo, Seong Hoon Jeong, Se Hyun Kim, Kyu Young Lee, Nam Young Lee, Yong Min Ahn, Yong Sik Kim, Myoung-Sun Roh
    Journal of Korean Medical Science.2011; 26(10): 1356.     CrossRef

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