Investigation of Indoor Solid Fuel and Kerosene Use as Tuberculosis Risk Factors

描述（由申请人提供）：在传染病中，结核病（TB）的死亡率仅次于艾滋病毒/艾滋病。世界上大约三分之一的人口感染了结核病。大多数感染者从未发展为活动性结核病，但形成了潜伏感染库，可发展为活动性疾病。因此，需要确定结核病感染或从感染进展为活动性结核病的可改变危险因素。发展中国家最常见的取暖和烹饪燃料是生物质（木材、牛粪和农业废弃物），燃烧时往往没有烟囱或通风设备。房子里充满了烟雾。生物质烟雾是否会增加结核病风险尚不确定。我们以前的工作是在尼泊尔进行的一项结核病病例对照研究，发现室内生物质燃烧作为加热燃料，以及使用煤油做饭或照明，可能是结核病的强烈危险因素。煤油的使用是否是结核病的危险因素以前没有调查过。然而，也有可能是选择偏差导致了我们的结果。因此，我们建议使用更严格的对照选择方法进行进一步的结核病病例对照研究，同时收集更广泛的室内燃料使用暴露数据。我们还将使用基于t细胞的干扰素-3释放试验确定潜伏性结核感染的对照，并在一组单独的数据分析中使用潜伏性结核阳性对照。在3.25年的时间里，我们将从尼泊尔博卡拉地区结核病中心招募650例新诊断的结核病病例，并从病例所在的村庄地区选择1300例频率匹配的对照。将向每位参与者发放一份关于烹饪、取暖和照明燃料使用情况的问卷，并寻求有关其他潜在结核病风险因素的信息。将对所有对照者进行潜伏结核感染检测。将从近四分之一的研究家庭（n=450）中获得空气交换率（AER）、CO和颗粒物排放的测量数据。我们将使用测量数据来模拟没有进行实际测量的家庭的AERs和排放水平。除了使用所有对照的数据分析外，我们还将仅使用结核感染呈阳性的对照进行一组平行分析。将使用所有对照获得的比值比（OR）除以仅使用潜伏感染对照获得的相应比值比，将提供对结核感染相对风险的估计。数据分析将侧重于确定煤油或生物质（作为取暖、照明或烹饪燃料）是否是结核病或感染的危险因素。研究结果表明生物质或煤油燃料是危险因素，这将对卫生政策和干预措施产生重大影响。如果煤油是一种危险因素，那么就有理由不像一些国际机构目前的政策那样，把它当作生物质的清洁燃料替代品。

DESCRIPTION (provided by applicant): Among infectious diseases, tuberculosis (TB) is second only to HIV/AIDS in causing mortality. About one-third of the world's population have TB infection. Most infected people never develop active TB, but form a reservoir of latent infections that can progress to become active disease. Therefore, modifiable risk factors for TB infection or for progress from infection to active TB need to be identified. The most common fuel for heating and cooking in developing countries is biomass (wood, cow dung and agricultural waste), often burnt without any chimney or ventilation. Houses fill with smoke. Whether biomass smoke increases TB risk is uncertain. Our previous work, a TB case-control study in Nepal, found indoor biomass burning as a heating fuel, and use of kerosene, for cooking or lighting, to be likely strong risk factors for TB disease. Whether kerosene use is a TB risk factor has not been investigated before. However, there is the possibility that selection bias was responsible for our results. Therefore, we propose a further case-control study of TB using a more rigorous control selection methodology, while collecting more extensive exposure data for indoor fuel use. We will also identify the controls with latent TB infection, using T-cell-based interferon-3 release assays and use the latent TB-positive controls in a separate set of data analyses. Over 3.25 years, we will recruit 650 newly diagnosed TB cases from the Pokhara Regional TB Center, Nepal, and 1300 frequency-matched controls selected from the village areas in which the cases live. Each participant will be administered a questionnaire on fuel use for cooking, heating and lighting, as well as seeking information on other potential TB risk factors. All the controls will be tested for latent TB infection. Measurements of air exchange rates (AER) and CO and particulate matter emissions will be obtained from nearly one-quarter of the study households (n=450). We will use the measurement data to model AERs and emission levels in the households where actual measurements are not made. In addition to the data analyses using all controls, we will carry out a parallel set of analyses using only the controls who are positive for TB infection. Division of the odds ratio (OR) obtained using all controls by the corresponding OR obtained using just latently infected controls will provide an estimate of the relative risk for TB infection. Data analysis will focus on identifying whether kerosene or biomass, as heating, lighting or cooking fuels, are risk factors for TB disease or infection. Findings showing either biomass or kerosene fuel to be risk factors, will have major implications for health policy and interventions. If kerosene is a risk factor, then this will provide justification for not treating it as a clean fuel alternative to biomass, as is currently the policy of some international agencies.