Epidemiology Provides Direction and Relevance to Contemporary Dermatological Investigation.

Abstract

Contemporary investigation in the dermatological sciences rests on a foundation that has been forged through several revolutions of methods and concepts. These have included transitions through: (1) clinical and then histopathological observations, (2) laboratory experimentation, first with proteins and subsequently through analyses based on genetic information, (3) large clinical trials, (4) epidemiological studies, and, most recently, (5) genetic analyses based on relatively large cohorts of patients with identical, or at least similar, diseases, including psoriasis and atopic dermatitis (inflammation), and melanoma (cancer). In this gathering of scientists from three continents, mechanisms by which dermatological investigators may accelerate their work by looking outside the strict confines of laboratory-based cutaneous biology, I wish to emphasize an important knowledge base by citing the growing relevance of epidemiology and its capacity to drive cutaneous biologists toward useful and realistic goals. The thesis of this presentation is that, beyond single gene errors, it is primarily through epidemiological studies that investigators will be able ultimately to direct their studies. A corollary of this thesis is that the vast majority of cutaneous biological studies should be directed toward human (and, by extension, animal) disease. I have chosen to introduce the information that supports this thesis through a series of questions: (1) beyond ultraviolet radiation, what environmental and dietary factors conspire in genetically predisposed individuals to cause melanoma? (2) What are the relationships between the gastrointestinal and the dermatological microbiomes and dermatological disease? (3) What is the extent to which environmental ‘‘insults’’, such as allergens and hydrocarbon microparticles, penetrate skin and modulate cutaneous, and even systemic, function? (4) Beyond ultraviolet radiation, what are the environmental accelerators of extrinsic cutaneous aging and pigmentation responses? Once available, answers to these questions will then provide insight into the laboratory work of the sort that is presented by others at this meeting. Moreover, answers to the questions will support the conclusion that epidemiological studies are needed to provide relevance to the investigative enterprise in dermatology. Borrowing an assertion from contemporary business economics: ‘‘If you can’t measure it, you can’t study it’’. MEETING REPORT