Elsevier

Mayo Clinic Proceedings

Volume 87, Issue 2, February 2012, Pages 151-160
Mayo Clinic Proceedings

Original article
Generalizability of Epidemiological Findings and Public Health Decisions: An Illustration From the Rochester Epidemiology Project

https://doi.org/10.1016/j.mayocp.2011.11.009Get rights and content

Abstract

Objective

To illustrate the problem of generalizability of epidemiological findings derived from a single population using data from the Rochester Epidemiology Project and from the US Census.

Methods

We compared the characteristics of the Olmsted County, Minnesota, population with the characteristics of populations residing in the state of Minnesota, the Upper Midwest, and the entire United States.

Results

Age, sex, and ethnic characteristics of Olmsted County were similar to those of the state of Minnesota and the Upper Midwest from 1970 to 2000. However, Olmsted County was less ethnically diverse than the entire US population (90.3% vs 75.1% white), more highly educated (91.1% vs 80.4% high school graduates), and wealthier ($51,316 vs $41,994 median household income; 2000 US Census data). Age- and sex-specific mortality rates were similar for Olmsted County, the state of Minnesota, and the entire United States.

Conclusion

We provide an example of analyses and comparisons that may guide the generalization of epidemiological findings from a single population to other populations or to the entire United States.

Section snippets

Sources of Data and Description of the Olmsted County Population

The REP medical records linkage system was initiated in 1966 to study disease epidemiology and patterns of health care among the residents of Olmsted County.5, 6 For more than 45 years, the REP has supported hundreds of studies of virtually all major diseases and has yielded more than 2000 publications.7 Details on the history of the REP and on the methods involved in linking medical records across health care providers in Olmsted County have been published elsewhere.5, 6 In this report, we

Description of the Olmsted County Population

Between 1970 and 2008, the population of Olmsted County increased from 84,104 to 141,360 individuals (a 68.1% overall increase). The percentage increase varied by age and was greatest in the older age groups (a 225.2% increase among persons 80 years of age and older compared with a 12.9% increase in persons 0 to 19 years old; Figure S1, Supplemental Material, available online at http://www.mayoclinicproceedings.org). The effect of these changes on the composition of the population is reflected

Discussion

Extrapolations of findings from studies conducted in selected populations must be judged on a study-by-study basis.1, 2 These extrapolations should take into account the specific demographic, ethnic, or socioeconomic characteristics of the populations being compared, as well as the likely association of these characteristics with the specific disease of interest.1, 2 In this article, we compared the demographic and socioeconomic characteristics and the mortality rates in the Olmsted County

Conclusion

Extrapolations and generalizations from studies in any single selected population must be judged on a study-by-study basis and should consider specific demographic or socioeconomic variables relevant to the study question. We provide an example of analyses and comparisons that may guide the generalization of epidemiological findings from a single population to other populations or to the entire United States. Epidemiological findings from any single population are best used when compared with

Acknowledgments

We thank Barbara Balgaard and Lori Klein for assistance with manuscript preparation and Brian Darling, Richard Gauthier, and Xiao Xie for assistance in compiling US Census data.

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  • Cited by (0)

    Grant Support: The Rochester Epidemiology Project infrastructure is funded by the National Institutes of Health (R01 AR030582 and R01 AG034676; Principal Investigator: Walter A. Rocca, MD, MPH).

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