Where you live may increase risk factors for asthma

Although researchers have known that disadvantaged urban residents are particularly vulnerable to asthma, this new research shows that specific characteristics of urban neighborhoods – over and above individual levels of poverty – can influence asthma levels among residents.

In particular, the study of 338 Chicago neighborhoods found asthma levels were highest in areas where there was a lack of cohesion and mutual support among residents and a low level of trust.

“People in poor neighborhoods who don’t trust one another, who live in a climate of fear, may be more likely to lock themselves in their apartments, where they are exposed to indoor allergens that can trigger asthma,” said Christopher Browning, co-author of the study and assistant professor of sociology at Ohio State University.

“The social context of neighborhoods can play a role in asthma.”

Browning conducted the study with Kathleen Cagney, assistant professor of health studies at the University of Chicago. Their results were published in a recent issue of the Journal of General Internal Medicine.

Asthma is one of the most common chronic diseases in the United States, affecting about 15 million people. However, it occurs disproportionately among urban, low-income and African-American people.

Browning said this study was designed to determine which factors about disadvantaged urban neighborhoods contribute to the prevalence of asthma.

The study combined statistics from three data sources from the 1990s to explore this question. The three surveys were the Metropolitan Chicago Information Center Metro Survey, the 1990 U.S. Census, and the Project on Human Development in Chicago Neighborhoods Survey.

This data allowed the researchers to examine asthma rates and a variety of social and individual risk factors in 338 Chicago neighborhoods. One of the key elements the researchers studied was the level of collective efficacy in each neighborhood. Collective efficacy is the extent to which people in a community trust one another, help each other and feel responsible for one another, Browning said.

“In a neighborhood with a strong sense of collective efficacy, there is a feeling that I’m going to be looking out for you and you’re going to be looking out for me,” he said.

The researchers found that in neighborhoods where collective efficacy was high, residents had a 15 percent probability of reporting asthma or breathing problems, compared to 21 percent in neighborhoods with low levels of collective efficacy.

This link between asthma and neighborhood collective efficacy stood up even after the researchers accounted for factors such as poverty, race, and health-related behaviors.

“The neighborhood context made a difference even when we controlled for a range of additional individual-level factors that are linked with asthma, such as poverty and smoking,” Browning said. “Neighborhoods do matter.”

Browning said it may be the level of trust in neighborhoods that is the key factor in collective efficacy that influences asthma levels. People who live in areas where they don’t trust their neighbors are probably exposed to high levels of indoor allergens.

“If residents feel uncomfortable walking outside or leaving windows open for fresh air, they may be continually exposed to high levels of indoors allergens such as dust mites or cockroaches,” he said. “This may be particularly bad in poor neighborhoods where housing is substandard and there are more allergens such as mold that could trigger asthma.”

In addition, neighborhoods with low collective efficacy may not have parks that people view as safe, to encourage people to leave their homes. Because people in these neighborhoods have a harder time working together, they may be less likely to fight to destroy abandoned buildings that exacerbate exposures to cockroaches and mold. And, Browning said, such neighborhoods often don’t have the ability to attract high-quality health services that could help them prevent or treat asthma.

“There’s a whole host of reasons why neighborhoods with low collective efficacy would be vulnerable to asthma,” Browning said. “But we believe it is the aspect of trust that has the biggest effect by leading people to lock themselves inside.”

This study suggests that researchers need to look beyond individual factors – such as income and health behaviors – to the broader social context when they are studying asthma, Browning said.