Variation in lung cancer risk by smoky coal subtype in Xuanwei, China

Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA.
International Journal of Cancer (Impact Factor: 5.09). 11/2008; 123(9):2164-9. DOI: 10.1002/ijc.23748
Source: PubMed


Lung cancer rates in Xuanwei County have been among the highest in China for both males and females and have been causally associated with exposure to indoor smoky (bituminous) coal emissions that contain very high levels of polycyclic aromatic hydrocarbons. There are numerous coal mines across the County. Although lung cancer risk is strongly associated with the use of smoky coal as a whole, variation in risk by smoky coal subtype has not been characterized as yet. We conducted a population-based case-control study of 498 lung cancer cases and 498 controls, individually matched to case subjects on age (+/-2 years) and sex to examine risk by coal subtype. Odds ratios (ORs) and 95% confidence intervals (CIs) for coal subtype were calculated by conditional logistic regression, adjusting for potential confounders. Overall, smoky coal use was positively and statistically significantly associated with lung cancer risk, when compared with the use of smokeless coal or wood (OR = 7.7, 95% CI = 4.5-13.3). Furthermore, there was a marked heterogeneity in risk estimates for specific subtypes of smoky coal (test for heterogeneity: p = 5.17 x 10(-10)). Estimates were highest for coal of the Laibin (OR = 24.8, 95% CI = 12.4-49.6) and Longtan (OR = 11.6, 95% CI = 5.0-27.2) coal types and lower for coal from other subtypes. These findings strongly suggest that in Xuanwei and elsewhere, the carcinogenic potential of coal combustion products can exhibit substantial local variation by specific coal source.


Available from: Aaron Blair
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    • "The lung cancer rate among those who routinely use smoky coal has shown considerable heterogeneity between geographic locations (Lan et al., 2008; Lin et al., 2012). This likely reflects different styles of coal preparation (such as making coal briquettes, or packing coal dust with local clay/soil) and/or compositional differences in coal between geographic sources. "
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    ABSTRACT: Xuanwei and Fuyuan counties in Yunnan Province, China have among the highest lung cancer rates in the country. This has been associated with the domestic combustion of bituminous coal (referred to as “smoky” coal). Additionally, significant geographical variation in cancer rates among smoky coal users has been observed, suggesting heterogeneity in fuel source composition and/or combustion characteristics. Research thus far has indicated that smoky coal emits high levels of polycyclic aromatic hydrocarbons (PAHs) and contains high concentrations of fine grained crystalline quartz, however, much of this research is limited in terms of sample size and geographic scope. In order to more fully characterise geochemical and elemental compositions of smoky and smokeless coal use in Xuanwei and Fuyuan, we carried out a large exposure assessment study in households in this region.
    Environment international 04/2014; 68C:94-104. DOI:10.1016/j.envint.2014.03.019 · 5.56 Impact Factor
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    • "). Further research in Xuan Wei County, including a case–control study consisting of 996 participants, has focused on subtypes of coal (Lan et al. 2008). Compared to users of non‑smoky coal or wood, persons exposed to smoky coal had seven times the odds of lung cancer, a finding that was evident in both men and women. "
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    • "Control subjects were randomly selected from the general population of Xuanwei (Lan et al. 2008). Controls were only eligible if there were farmers. "
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