3. Epidemiology

Epidemiology is a discipline that focuses on the distribution and risk factors for various health events or disease outcomes. This chapter describes how epidemiology seeks to determine if a particular risk factor is likely to cause a particular health event in firefighters; the processes used to undertake case-control and cohort studies, types of epidemiological research health study designs that are typically used to determine health event causation, including specifying their advantages and disadvantages; basic epidemiological concepts and terms; and will introduce a checklist of criteria and the process used to critically appraise and evaluate existing case-control and cohort health studies in the literature. Meta-analysis, where results from case-control and cohort studies can be combined to get an overall estimate of risk for a particular factor(s) will also be discussed, as well as its advantages and disadvantages. The chapter is intended to orient the non-technical expert to epidemiological terms, particular studies, and their value in relation to identifying factors that cause health events in firefighters.