204176 Utilization of high-resolution satellite data from the National Land Cover Data: The relationship between hypertension and living environment in the Reasons for Geographic And Racial Differences in Stroke (REGARDS) Study

Monday, November 9, 2009

Leslie A. McClure, PhD , Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL
William Crosson, PhD , Public Health Applications, NASA/USRA, Huntsville, AL
Mohammad Al-Hamdan, PhD , Public Health Applications, NASA/USRA, Huntsville, AL
Shia Kent, MSPH , Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL
Sue Estes, MS , Public Health Applications, NASA/USRA, Huntsville, AL
Dale Quattrochi, PhD , Public Health Applications, NASA/USRA, Huntsville, AL
Maurice Estes, PhD , Public Health Applications, NASA/USRA, Huntsville, AL
Background: Coincident with global expansion of urban areas has been an increase in hypertension (HTN). It is unclear how much the urban environment contributes as a risk factor for blood pressure differences, and how much is due to a variety of environmental, lifestyle, and demographic correlates of urbanization.

Objectives/Purpose: The purpose of this study is to utilize high resolution satellite data to examine the relationship between living environment defined as urban, suburban, and rural and hypertension in selected regions from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort.

Methods: REGARDS is a national cohort of 30,228 participants from the 48 contiguous United States. Data from 4 metropolitan areas (Philadelphia, Atlanta, Minneapolis and Chicago) and surrounding regions were used for this study (n=3928). We used Land Cover/Land Use (LCLU) information from the Landsat-derived 30-meter National Land Cover Data (NLCD) to characterize participants into urban, suburban or rural living environments.

Results: Overall, 1996 (61%) of the participants were hypertensive. In univariate models, we found that increasing degree of urban living environment is associated with prevalence of HTN (Suburban vs. Rural: 1.3, 95% CI: 1.1-1.6; Urban vs. Rural: 1.7, 95% CI: 1.4-1.2), but that after adjustment for known HTN risk factors, the relationship was no longer present (Suburban vs. Rural: 1.1, 95% CI: 0.84-1.4; Urban vs. Rural: 1.2, 95% CI: 0.85-1.6).

Conclusions: LCLU data can be utilized to characterize the living environment, which in turn can be applied to studies of public health outcomes. Further study regarding the relationship between HTN and living environment should focus on additional characteristics of the associated environment, such as pollutants and the built environment.

Learning Objectives:
(1) Describe the methodology by which the Land Cover/Land use (LCLU) data were processed; (2) Articulate the utility of using LCLU data to characterize the living environment as urban, suburban, and rural; (3) Evaluate the relationship between living environment and blood pressure.

Keywords: Public Health Informatics, Geographic Information Systems

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I did the data analysis and helped draft the manuscript.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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