In Reply: In response to Dr Zhao and colleagues, the population of Olmsted County receives a substantial proportion of its care at Mayo Clinic and is mostly white. These points, acknowledged in our article, indicate that our study needs replication in groups not represented in the county; no regional population could be representative of a whole country, let alone the world. However, the medical records linkage system of the Rochester Epidemiology Project encompasses all local providers of medical care, and studies under the auspices of the Rochester Epidemiology Project have consistently demonstrated that trends observed in Olmsted County for chronic diseases in general and cardiovascular diseases in particular are similar to those observed in similar populations in the United States and the world.1 Thus, Olmsted County data are of broad relevance.
Roger VL, Adabag AS, Weston SA. Surveillance of Sudden Death After Myocardial Infarction—Reply. JAMA. 2009;301(11):1123-1124. doi:10.1001/jama.2009.285