Ethnicity and race as epidemiological variables: centrality of purpose and context
Introduction Race and ethnicity are, probably, the most controversial and difficult of all commonly used epidemiological variables. They are also among the most effective in contributing to one crucial aspect of the epidemiological strategy: dem onstrating population variations in disease (Polednak 1989, Smaje 1994). We are in the midst of a change of paradigm : a reconsideration of the race concept. It is a tim e of confusion and the need for reasoned debate is great.Ethnicity and race are integral to much m odern epidemiology and public health (Jones et al. 1991, Williams 1994, Ahdieh and H ahn 1996) but the historical legacy of these concepts in science is a long one. Racially orientated description and analysis was used by Hippocrates (Chadwick and M ann 1950), for whom geographical location and climate were closely linked to concepts of race. In the H ippocratic w ritings population characteristics such as cowardice, feebleness and m ental agility were associated with differing clim ate and geography, and hence races. Currently, the most influential concept of race in medical research, despite its flaws scientifically (Ruper 1975, Stepan 1982, Barkan 1992), rem ains tha t of group differences due to biology. D espite all the criticism s, this rem ains the crux of dictionary definitions (Ellison 1998). This idea has been so powerful tha t societies have become racialised, i.e. they see race as a natural, prim ary (and neutral) means of grouping hum ans and understanding differences between them.O n the weight of 150 years of scientific analysis and popular usage, race is interpreted as the social group a person belongs to because of a mix of physical features, themselves attributable to genetic differences arising from evolution in a particu lar place. Physical differences, particularly skin colour, have provided an easy route for pu tting racism into practice. The theoretical concept of biological races has become an underpinning feature of racialised societies and, in turn , has created widely used social categories.