Grant: Project Grant

Human health is strongly impacted by lifelong chemical exposures in our environment. For example, chronic exposure to numerous toxins from cigarette smoke is a leading preventable cause of death in Canada and globally. The majority of these deaths are from cancers, heart disease and respiratory illnesses. However, the impact of tobacco smoke on disease risk is region-specific and dependent on genetics, diet, lifestyle and socioeconomic factors. These effects contribute to differences in health outcomes since current smokers in high-income countries, such as Canada, may have greater risk for death and chronic disease burden than individuals from middle- and low-income countries despite smoking at the same intensity level. Yet, the causes for these striking differences in tobacco-related deaths and disease burdens remain uncertain - this is the 'smoking paradox' that our research will address. Our proposal aims to decipher the causes for differing health outcomes from tobacco smoking between countries, which is subject to error as epidemiological studies rely on self-reported smoking history from questionnaires. We will use innovative methods based on mass spectrometry for quantitative analysis of metabolites in urine reflecting tobacco smoke exposure from 8,073 participants in the Prospective Urban Rural Epidemiological (PURE) study. This approach is critical for reliable assessment of tobacco exposure and nicotine dependence in active smokers not feasible by self-reports. For the first time, we will measure a broad panel of urinary biomarkers of tobacco smoke exposure and their potential harm in current and never smokers from 14 different countries while also exploring the complex interactions of local air pollution and dietary habits on disease risk. Our proposal will transform environmental epidemiology by developing evidence-based public health policies to reduce disease burden in vulnerable populations not achievable by current tobacco control measures.