While study findings showed worse health and poorer quality of life among people living in lower-income areas, they also showed poorer lung function among those living in suburbs, where people tended to own newer homes in less densely populated neighborhoods.
The study, conducted by researchers from the University of California, San Francisco, is published in the January issue of the European Respiratory Journal.
The analysis did not pinpoint exposures that might be linked to these population effects, but most researchers believe water-damaged housing stock, proximity to high traffic flow, industrial pollution, and social environmental stress are key contributors to health problems in poorer neighborhoods. The study raises the possibility that more frequent household pet ownership may be one factor in lower lung function in suburban-related health exposures, although larger backyards with more allergenic plants could be a contributor.
"Our research could be subtitled 'No Man is an Island,'" said Paul Blanc, MD, UCSF professor of occupational and environmental medicine and lead author of the study. "The study findings underscore that asthma is a complex problem that does not simply affect people in isolation."
"Even if individual risk factors such as poor access to medical care can be overcome, different communities have different asthma patterns, and strategies for prevention and treatment must take this into account," he said.
Blanc cites the need for studies to nail down the community-wide physical and social environmental factors that contribute to asthma and poorer respiratory health.
The study examined the respiratory health and self-reported socioeconomic status of more than 400 adults suffering from either asthma, chronic nasal or sinus conditions, or both. Most of the people live in northern California. Participants had previously been interviewed at least once as part of the researchers' on-going study. Some were also visited in their homes in order to directly assess their health status and environment.
The investigators were able to use computer mapping of residential location, a process known as geocoding, in order to link interview data with general U.S. census information for each person's surroundings. In this way they could characterize different area-wide socioeconomic factors such as percentage of home ownership, population density, average incomes, number of single-parent households, and local unemployment rates. By combining these factors, the investigators saw a strong link between the socioeconomic status of the area and health measures in asthma.
"This has been seen with other diseases besides asthma, although not usually as an effect over and above personal economic status," Blanc says. "Where we live doesn't predict our fate, but it surely links to our health. We should identify the key environmental agents and work to decrease how much people are exposed to them in their daily lives."
Co-authors on the study, all at UCSF, are Mark Eisner, MD, associate professor of occupational and environmental and pulmonary and critical care medicine; Irene H. Yen, PhD, epidemiologist; Gillian Earnest, MS, statistician; Laura Trupin, MPH, research associate; and Naomi Friedling, BA, research assistant, all in medicine; Hubert Chen MD, research fellow in the division of pulmonary and critical care medicine and the Cardiovascular Research Institute; Patricia P. Katz, PhD, associate professor of medicine; and Edward H. Yelin, PhD, professor of rheumatology, both also in the Institute for Health Policy Studies; and John R. Balmes, MD, professor of medicine.
The research was funded in part by the National Institute of Environmental Health Sciences.
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