Methods for Retrospective Geocoding in Population Studies: The Jackson Heart Study

Abstract

The increasing use of geographic information systems (GIS) in epidemiological population studies requires careful attention to the methods employed in accomplishing geocoding and creating a GIS. Studies have provided limited details,hampering the ability to assess validity of spatial data. The purpose of this paper is to describe the multiphase geocoding methods used to retrospectively create a GIS in the Jackson Heart Study (JHS). We used baseline data from 5,302 participants enrolled in the JHS between 2000 and 2004 in a multiphase process to accomplish geocoding2 years after participant enrollment. After initial deletion of ungeocodable addresses(n=52), 96% were geocoded using ArcGIS. An interactive method using data abstraction from participant records, use of additional maps and street reference files,and verification of existence of address, yielded successful geocoding of all but 13 addresses. Overall, nearly 99% (n=5,237) of the JHS cohort was geocoded retrospectively using the multiple strategies for improving and locating geocodable addresses. Geocoding validation procedures revealed highly accurate and reliable geographic data. Using the methods and protocol developed provided a reliable spatial database that can be used for further investigation of spatial epidemiology. Baseline results were used to describe participants by select geographic indicators, including residence in urban or rural areas, as well as to validate the effectiveness of the study's sampling plan. Further, our results indicate that retrospectively developing a reliable GIS for a large, epidemiological study is feasible. This paper describes some of the challenges in retrospectively creating a GIS and provides practical tips that enhanced the success.

Double-jeopardy: The joint impact of neighborhood disadvantage and low social cohesion on cumulative risk of disease among African American men and women in the Jackson Heart Study

“…The study population included adults aged 21–85 from three counties in the Jackson Metropolitan Area—Hinds, Madison, and Rankin— and was obtained using four sampling strategies: a random sample of adults drawn from a commercially available list of households with adults aged 35–84 (17%); volunteers aged 35–84 recruited through participant referral or outreach activities (30%); participants in the Jackson field center of the Atherosclerosis Risk in Communities (ARIC) study (31%); and relatives of JHS participants, ≥ 21 years of age comprising the JHS Family Sub-Study (22%). A total baseline sample of 5,301 participants (men, n=1,906; women, n=3,395) were recruited into the JHS and 98.8% (n=5,236) were retrospectively geocoded to 102 census tracts (Robinson et al, 2010). Hickson et al (2011) conducted a spatial Bayesian analysis of the JHS which showed that at the census tract level, the sample was representative of the underlying African American population living within the Jackson Metropolitan Area with two exceptions: the distribution of JHS women was more representative than JHS men, and participants residing in mixed and predominantly African American census tracts were more representative than those residing in predominantly white census tracts.…”

Neighborhood Disadvantage and Cumulative Biological Risk Among a Socioeconomically Diverse Sample of African American Adults: An Examination in the Jackson Heart Study

“…The study population included adults aged 21-85 residing in the Jackson Metropolitan area and was obtained using four sampling approaches: a random sample of adults drawn from a commercially available list of households with adults aged 35-84 (17%); volunteers aged 35-84 recruited through participant referral or outreach activities (30%); participants in the Jackson field center of the Atherosclerosis Risk in Communities (ARIC) study (31%); and relatives of JHS participants, ≥21 years of age comprising the JHS Family Sub-Study (22%). A total of 5,301 participants were recruited into the JHS of whom 99% were retrospectively geocoded to 102 census tracts (32). …”

Socioeconomic Position Is Positively Associated With Blood Pressure Dipping Among African-American Adults: The Jackson Heart Study

“…Each participant’s residential mailing address was geocoded to the census tract and used as a proxy for neighborhood. 25 Neighborhood SEP was defined as the median household income from 2000 US Census. Neighborhood SEP was divided into tertiles: ≤$25,900 (33.6%), $26,000–$35,000 (32.9%), and >$35,000 (33.6) and also examined continuously in s.d.…”