Selecting appropriate study designs to address specific research questions in occupational epidemiology

Historically, occupational epidemiology studies have often been initiated in response to concerns about apparent workplace hazards. Such concerns typically are motivated by observations of disease clusters in a workforce, findings from previous epidemiological studies of similar workplace settings, or evidence derived from other disciplines, such as toxicology, suggesting potential health impairment from workplace exposures. Occupational epidemiologists employ a variety of study approaches to investigate work- related illness and injuries. Many of these are familiar designs that are commonly applied in other branches of epidemiology, but some are characteristic to occupational studies. The choice of study design is nearly always determined by the research question of interest, and by feasibility constraints. In this brief review, we will summarise some study design features, including particular strengths and limitations, with an emphasis on selecting the design that should be most appropriate for investigating the exposure/ health outcome association of interest. Readers seeking more in- depth discussions of study designs are encouraged to consult text books on occupational epidemiology(1-3) or general epidemiology texts.(4 5)