The ubiquitous use of racial categories in bone density and osteoporosis research has contributed to widely held erroneous assumptions about inherent racial differences in bone mineral density (BMD). Racial concepts in the BMD literature are often not defined and ambiguous, frequently leading to conclusions about biological or inherent racial differences in BMD variation. In addition, racial variables are often treated as singular variables instead of complex proxies for several attributes that can affect the skeleton, such as diet, behavior, environment, and socioeconomic status.
The concept of race, as understood in anthropology, is inconsistent with presumptions of biological differences. Anthropological views on the concept of race, however, are not monolith, and other scientific disciplines do not necessarily subscribe to similar notions. In fact, clinical and medical research quite often uses racial categories as convenient shortcuts for biological differences between populations. This common practice frequently results in interpretations of racial differences in BMD that default to biological explanations, without carefully measuring other social or environmental covariates. Such flaws in the interpretation of racial BMD differences obscures rather than clarifies the underlying causes of BMD variation.
This dissertation addresses this problem by examining social, economic, and lifestyle variation in bone density more directly, without assuming that racial variables contribute meaningful biological information. This analysis explores intra-group BMD variation in a sample of African-American participants from Detroit, Michigan. Systematic racial differences in BMD commonly attributed to biological factors may be more effectively captured by demographic (age, sex, and body size), lifestyle (diet, physical activity and smoking), and socioeconomic status (income, education, occupation and other social features). In limiting this investigation of BMD to one, traditionally understudied group, several pitfalls associated with racial categories are avoided and advantages are gained. Investigation of social, economic, demographic, and behavioral characteristics important to bone mass can be examined directly without resorting to ambiguous notions of inherent racial differences. In addition, the complex relationship between race and factors that can affect BMD can be clarified.
This analysis uncovered previously unrecognized correlates with BMD and revealed that the relationship between variables associated with economic strain and BMD is likely to be discordant. The complex relationship between socioeconomic status and BMD may not be suited to analyses that use composite socioeconomic status scores. This analysis determined that body size was one of the most important factors to BMD differences. Systematic body size differences between populations may be one of the primary causes for racial BMD differences seen in the U.S.
Many anthropologists and public health experts advocate moving away from presumptions of racial biological difference and towards explanations based in social and environmental causes. This analysis represents one facet of that initiative which considers bone mass and bone density.