Study following 32,000 black women found increased depressive symptoms tied to asthma incidence
Stress is the likely pathway between depression and adult-onset asthma in African-American women, according to a new study by researchers at Boston University’s Slone Epidemiology Center.
“The hypothesized mechanism linking depressive symptoms to asthma incidence is stress and its physiological consequences—particularly, effects on the immune system and the airways,” says study lead author Patricia Coogan, a research professor of epidemiology at Slone. “Psychological stress can bias the immune system to responses that might contribute to asthma.”
In the study, Coogan and her team followed nearly 32,000 African-American women—participants in the long-running Black Women’s Health Study—who completed health questionnaires every two years. The researchers found that as the frequency of depressive symptoms increased, the incidence of adult-onset asthma did, too.
Several smaller studies of depression and asthma incidence found similar results in mostly white populations. But, says Coogan, “I was surprised at the magnitude of the relative risk in our highest category of depressive symptoms.”
According to the investigators, 11.6 percent of black women currently have asthma, and 13.1 percent have a lifetime prevalence of major depressive disorder. When the conditions occur concurrently, both are usually more severe. Children typically experience intermittent asthma symptoms in response to allergens or respiratory infections, but adults with newly diagnosed asthma tend to have persistent symptoms that require daily medications to control. If not properly treated, asthma can be fatal.
Though this new research does not establish a causal relationship between depression and asthma, it does suggest that depressive symptoms can precede asthma. “This is very early in this research,” Coogan says. “What we can state with certainty now is that there is an association” between depressive symptoms and the onset of adult asthma. “Given the high prevalence of both asthma and depression in women, the association is of public health importance.”
Further research is recommended. Childhood asthma has been much studied, but experts know little about the adult-onset version of the disease.