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.

Download full-text


Available from: Aaron Blair
  • Source
    • "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. "
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Apr 2014 · Environment international
  • Source
    • "). 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. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Indoor air pollution (IAP) derived largely from the use of solid fuels for cooking and heating affects about 3 billion people worldwide, resulting in substantial adverse health outcomes, including cancer. Women and children from developing countries are the most exposed populations. A workshop was held in Arlington, Virginia, 9–11 May 2011, to better understand women’s and children’s potential health effects from IAP in developing countries. Workshop participants included international scientists, manufacturers, policy and regulatory officials, community leaders, and advocates who held extensive discussions to help identify future research needs. Objectives: Our objective was to identify research opportunities regarding IAP and cancer, including research questions that could be incorporated into studies of interventions to reduce IAP exposure. In this commentary, we describe the state of the science in understanding IAP and its associations with cancer and suggest research opportunities for improving our understanding of the issues. Discussion: Opportunities for research on IAP and cancer include studies of the effect of IAP on cancers other than lung cancer; studies of genetic factors that modify susceptibility; studies to determine whether the effects of IAP are mediated via germline, somatic, and/or epigenetic changes; and studies of the effects of IAP exposure via dermal and/or oral routes. Conclusions: IAP from indoor coal use increases the risk of lung cancer. Installing chimneys can reduce risk, and some genotypes, including GSTM1-null, can increase risk. Additional research is needed regarding the effects of IAP on other cancers and the effects of different types of solid fuels, oral and dermal routes of IAP exposure, genetic and epigenetic mechanisms, and genetic susceptibility.
    Full-text · Article · Jul 2012 · Environmental Health Perspectives
  • Source
    • "Control subjects were randomly selected from the general population of Xuanwei (Lan et al. 2008). Controls were only eligible if there were farmers. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Xuanwei, China, experiences some of the highest rates of lung cancer in China. While lung cancer risk has been linked to the household use of bituminous coal, no study has comprehensively evaluated the risk of lung cancer associated with the mining of this coal in Xuanwei. In Xuanwei, coal is typically extracted from underground mines, without ventilation, and transported to the surface using carts powered by manpower or electricity. We evaluated the risk of lung cancer and working as a coal miner, in the absence of diesel exhaust exposure, in a population-based case-control study of 260 male lung cancer cases and 260 age-matched male controls with information on occupational histories. Odds ratios (ORs) and 95% confidence intervals (CIs) for working as a coal miner and years of working as a coal miner were calculated by conditional logistic regression, adjusting for potential confounders, such as smoking and household coal use. We observed an increased risk of lung cancer among coal miners (OR = 2.7; 95%CI = 1.3-5.6) compared to noncoal miners. Further, a dose-response relationship was observed for the risk of lung cancer and the number of years working as a coal miner (P(trend)  = 0.02), with those working as miners for more than 10 years experiencing an almost fourfold increased risk (OR = 3.8; 95%CI = 1.4-10.3) compared to noncoal miners. These findings suggest that coal mining in Xuanwei may be a risk factor for lung cancer.
    Full-text · Article · Jan 2012 · American Journal of Industrial Medicine
Show more