Ethnicity and disease prevention.

Ethnic variations in health present a useful paradigm for the study of disease etiology. The knowledge base in this area has expanded dramatically in recent years, both as a result of research across cultures and studies within multiethnic societies. The growth in descriptive information, however, has not always been paralleled by an increase in causal explanations. At both the theoretical and practical levels confounding remains an unsolved problem. Because of the frequent correlation between ethnicity, socioeconomic status, and risk exposures it is often difficult to isolate the relative impact of genetics and external risk factors. The importance of variation in allele frequencies in determining ethnic diesease patterns is further complicated by the difficulty in providing precise ethnic group designations. Inference regarding causal relationships becomes particularly challenging for polygenic disorders like hypertension and non-insulin-dependent diabetes mellitus, where good candidate genes are not available. At the same time, exposures are often known before the genetic basis of susceptibility has been identified and provide a practical basis for prevention. Prevention campaigns should be merged with etiologic research whenever possible and close collaboration among scientists working in public health and epidemiology and those based in genetics and biology would facilitate development of an appropriately balanced strategy. © 1993 Wiley-Liss, Inc.