14 The future of genetic case-control studies

The case-control study design has been a veritable workhorse in epidemiological research since its inception and acceptance as a valid and valued field of inquiry. The reasons for this owe to the simplicity of the required sampling and the (potential) ease of analysis and intepretation of results. Unfortunately, there are a number of problems that plague the use of the case-control design in assessing relationship between genetic variation and disease susceptibility in the population at large. Many of these problems are entirely analogous to problems that inhere in applications of the case-control design in nongenetic settings. These problems include stratification, the assessment of statistical significance, heterogeneity, and the interpretation of multiple outcomes or phenotypic information. In this chapter we described 10 problems thought to plague genetic case-control studies and offer potential solutions to each. Many of our proposed solutions require the use of multiple DNA markers to accommodate the genetic background of the individuals sampled as cases and controls. It is hoped that our discussions and proposals will spark further debate about the analyses and ultimate utility of the case-control study in genetic epidemiology research.