I thank Dr Carter for his response to my editorial.1 Dr Carter cites examples of skin diseases that are more prevalent in "blacks." The key issue, however, is how he would try to define race when comparing groups of people in research studies.
Early in my career, I worked in an area of London where 40% of the population was Black Caribbean or Black African. That was where I developed the hypothesis that atopic dermatitis was more common in people from these ethnic groups. To test this hypothesis, I envisaged that it would be easy to come up with a definition of a "black" person based on skin pigment, hair type, facial features, and body habitus that would satisfy a small clinical study. And that is when I ran into major problems. While it appeared easy to define a typical "black" person, I encountered a large "gray" or boundary zone. Some "black" children had lighter skin than children of Mediterranean parentage, and those with parents of mixed ethnic groups (which constituted up to 20% of "black" families) were somewhere in between. Parents also rightly became irritated at me trying to pigeonhole such a large group of diverse ethnic groups into just one. I quickly gave up on the notion of trying to develop a scientific definition of a "black" person that could be used for a study on atopic dermatitis. I returned to the hypothesis some years later, seeking advice from epidemiologists and the local black community who recommended using self-nominated ethnic groups. This time, parents were much happier to help with the study because the classification made much more sense to them. Not once did parents give me incompatible answers. That study produced useful information that has prompted further studies.2
Williams HC. Race vs Ethnicity in Dermatology—Reply. Arch Dermatol. 2003;139(4):539–540. doi:10.1001/archderm.139.4.539-a