ABSTRACT
Epidemiology has been described as a discipline and not as a science (1). As a discipline, epidemiology comprises a set of principles and approaches that, in their application to the study of human ill health, focus on the distribution and determinants of health-related states and disease in populations (2). The determinants of disease are usually considered under two broad headings-environmental and host factors. In the context of occupational asthma (OA), the environmental factors that are of interest are those encountered in the workplace and include all exposures, whether gaseous or airborne particulates, physical stress (heat and/or cold), or factors related to workplace organization. A determinant has been defined as ‘‘any physical, biological, social, cultural, or behavioral factor that influence the study outcome (in the present context, OA)’’ (2). It may be causal or not, and can increase or decrease risk; risk factors may be primary (i.e., they increase incidence) or secondary (i.e., they increase severity and/or trigger symptoms) (3).
