ABSTRACT
This chapter discusses the importance of case-control studies in epidemiological research, and their specific application to studies of the role of beta agonist therapy in asthma mortality. Until recently, epidemiological studies of the role of beta agonists in asthma mortality had been primarily descriptive. These largely involved calculating annual mortality rates from asthma and comparing the time trends in mortality with the time trends in beta agonist sales in various countries. Unfortunately, cohort or case-control study of asthma mortality was never conducted because the epidemic declined before there was time to commence such a study. In case-control study, a group of persons with a disease is compared with a control group of persons without the disease with respect to their past exposure to a particular factor. Case-control studies are the most practicable and efficient form of epidemiological research when studying rare outcomes, and for this reason alone case-control studies are the optimal approach for investigating the causes of asthma mortality.
