The New Epidemiology: putting the pieces together in complex disease aetiology.

The genomics revolution continues to transform epidemiology, clinical medicine, and drug discovery.1–7 The generation of new genomic knowledge and its integration into epidemiological, molecular, and clinical research projects in industry and academia are increasing exponentially.8 The genetic basis of disease susceptibility, disease progression and severity, and response to therapy for many complex conditions has been increasingly emphasized in clinical research and epidemiology, with the ultimate goal of improving preventive strategies, diagnostic tools, and therapies.4,5,9,10 These dynamic trends in epidemiology are embodied in this special issue of the International Journal of Epidemiology, which has the theme ‘Genetic Epidemiology’. Khoury et al.11 and Jablonka12 provide outstanding reviews of the many ways in which genetic and genomic knowledge is being incorporated into mainstream epidemiology and of the growing integration of these disparate disciplines. Iliadou et al.,13 Sparks et al.,14 Lewis and Brunner,15 McKeown-Eyssen et al.,16 Morita et al.,17 Keavney et al.,18 and Gatto et al.19 provide a number of interesting and instructive illustrations of the praxis of adding genetic information to studies established to investigate epidemiological hypotheses. McNeill et al.20 describe an investigation of the interrelationships between genetic and environmental determinants on complex phenotypes—a further area of growing interest for both genetics and epidemiology.