The overall aim of this component is to provide an analytic framework for the assessment of empirical evidence on the burden of disease and injury attributable to major population exposures in the context of the Global Burden of Disease 2000 Study. It does so by reviewing the conceptual issues in the calculation and interpretation of attributable fractions thereby providing a coherent conceptual framework for comparing disease and injury burden due to risk factor exposures. Related goals are to advance existing knowledge about risk factors for non-communicable disease, especially to advance knowledge about major blood-based risk factors through a large prospective study in a middle-income developing country (Mexico). The specific aims are: 

• Conceptual framework for comparative risk assessment: To provide a clear and coherent framework for comparing and interpreting the disease and injury burden attributable to specific population exposures.
• Evidence for known risk factors: To provide reliable evidence on the importance and interactions of known risk factors for chronic diseases in a large, middle-income adult population. 

• Identification of new risk factors: To investigate and quantify the importance of other, blood-related factors as causes of premature death including genetic polymorphism, antibodies to many infective agents, hormones and other signal molecules, various coagulation and inflammatory factors, micronutrients, and protein glycosylation.