Multiethnic Cohort Study
The Multiethnic Cohort (MEC) study was a prospective study which included people from Hawaii and California. It recruited people from the main cultural groups residing there – Native Hawaiians, African Americans, Latinos, Japanese Americans, and whites. In such MEC studies, researchers sample subgroups of people belonging to one of several preselected cultural groups. These groups were expected to have a different prevalence of a given disease, and the study aimed to investigate which risk factors accounted for such differences. The MEC study included over 215,000 men and women. Generally speaking, by running the study prospectively and simultaneously for all ethnic subgroups, effects of “historical events” (e.g., development of a new treatment for a disease, a known public figure develops an illness, or an infectious epidemic) occur for all participants at the same time. Furthermore, by conducting the study prospectively, researchers used similar assessment tools and controlled for the identical confounders, across ethnic groups. This resulted with more methodological rigor and thus greater inferential validity in the results.
Numerous studies emerged from the MEC study, in relation to several health outcomes. Initially planned to examine ethnic differences in cancer, this research found that Native Hawaiians have 65 % higher risk of breast cancer than white Americans. One explanation for this excess, which was partly confirmed, was that Native Hawaiians have more frequent polymorphisms in sex steroid pathways (Pike et al. 2002). Another study compared the rates of mortality from myocardial infarction and other cardiac reasons, between those ethnic groups. Native Hawaiians and African Americans had the highest death rates, which were mostly explained by their higher prevalence of diabetes and hypertension (Henderson et al. 2007). Such studies enable health policymakers and public health professionals to target specific risk factors in specific ethnic groups, to prevent such outcomes. Furthermore, MEC studies can shed light on “nature-nurture” interactions, where environmental factors (e.g., smoking, diet, psychosocial stressors, housing conditions) and ethnicity (proxy measure of genetic risk) or actual genetic polymorphism may interact in relation to onset of diseases. By identifying the most “at-risk” subgroups and their risk factors, preventative measures may be taken to result in more equal health status among different ethnic groups.
References and Further Readings
- Pike, M. C., Kolonel, L. N., Henderson, B. E., Wilkens, L. R., Hankin, J. H., Feigelson, H. S., et al. (2002). Breast cancer in a multiethnic cohort in Hawaii and Los Angeles: Risk factor-adjusted incidence in Japanese equals and in Hawaiians exceeds that in whites. Cancer Epidemiology, Biomarkers & Prevention, 11, 795–800.Google Scholar