Today’s guest post comes from Dr Jameson Voss. You can find more on Jameson at the bottom of this post. You can find out how to submit your own Obesity Panacea guest post here.
Obesity is a complex and multifactorial chronic disease that remains a military and public health priority in the United States. Recently, we’ve identified a strong association between obesity prevalence and altitude within the US. Our findings were surprising because they indicated the magnitude of this association was large and the pattern of association exhibited a curvilinear dose response in 500 meter categories of altitude. There was a 4-5 fold increase in obesity prevalence at low altitude as compared with the highest altitude category after controlling for diet, activity level, smoking, demographics, temperature, and urbanization. We published our findings in the International Journal of Obesity (advance online publication doi:10.1038/ijo.2013.5) and presented at the 2013 American College of Preventive Medicine conference.
The process we used is easily reproducible. We combined several publicly available national datasets using statistical software and geographic information systems using the county of residence as a common linkage across datasets. For a basic visualization, Figure 1 shows the Centers for Disease Control and Prevention’s publicly available map with projected obesity prevalence for each county adjusted only for age. This map was created based on similar data as the source for our study, but we used actual self-reported height and weight rather than the modeling shown in Figure 1 and we adjusted for age, sex, race/ethnicity, physical activity compliance, fruit and vegetable consumption, smoking status, employment status, education, urbanization, temperature category and income. By comparison, Figure 2 from http://ned.usgs.gov/ shows the topography of the United States.
While it is always important to remember correlation does not prove causation, in this case, we already know hypoxia causes anorexia and weight loss based on well controlled interventional data. This effect is biologically plausible based on the relationship between hypoxia and leptin signaling, norepinephrine and sympathetic tone, non-erythroid erythropoietin receptor signaling, and the metabolic demands at high altitude. We hope additional research will help clarify the mechanisms and long term health effect of either high altitude residence or normobaric hypoxia. These results, showing a large magnitude of association, provide some optimism that this is a worthy line of research.
About the Author: Jameson Voss is a third year Preventive Medicine Resident at the Uniformed Services University of the Health Sciences. His research focus is on obesity.
Voss, J., Masuoka, P., Webber, B., Scher, A., & Atkinson, R. (2013). Association of elevation, urbanization and ambient temperature with obesity prevalence in the United States International Journal of Obesity DOI: 10.1038/ijo.2013.5