Original Article
Korean J Prev Med. 2000; 33(1): 125-133.
Relationship between Occupational Electromagnetic Field Exposure and Leukemia: A Meta-Analysis.
Yong Sung Cho, Yoon Shin Kim, Hae Hiang Song, and Seung Cheol Hong
1Department of Industrial Medicine, Hanyang University.
2Department of Biostatistics, College of Medicine, Catholic University.
3Environmental Technology Center, NIER.
OBJECTIVES: This study uses meta-analysis methodology to examine the statistical consistency and importance of random variation among results of epidemiologic studies of occupational electromagnetic field exposure and leukemia. METHODS: Studies for this meta-analysis were identified from previous reviews and by asking researcher active in this field for recommendations. Overall, 27 studies of occupational electromagnetic field exposures and leukemia were reviewed. A variety of meta-analysis statistical methods have been used to assess combined effects, to identify heterogeneity, and to provide a single summary risk estimate based on a set of simiar epidemiologic studies. In this study, classification of exposure metircs on occupational epidemiologic studies are reported for (1) job classification (20 individual studies); (2) leukemia subtypes (13 individual studies); and (3) country (27 individual studies). RESULTS: Results of this study, an inverse-variance weighted pooling of all the data leads to a small but significant elevation in risk of 11% (OR=1.11, 95% CI : 1.06~1.16) among 27 occupational epidemiologic studies. Publication bias was assessed by the 'fail-safe n' that may be not influence for all combined results exception a few categories, ie, "power station operators" and "electric utility workers" by job classification on occupational study. And all combined odds ratio results were similar for fixed-effects models and random-effects models, with slightly higher risk estimates for the random-effects model in situations where there was significant heterogeneity, ie, Q-statistic significant (p<.05). CONCLUSIONS: We found a small elevation in risk of leukemia, but the ubiquitous nature of exposure to electromagnetic fields from workplace makes even a weak association a public health issue of substantial power to influence the present overall conclusion about relationship between electromagnetic fields exposure and leukemia.
Keywords : Meta-analysis;Electromagnetic field;Leukemia;Workplace