African-American women with high levels of depressive symptoms have greater likelihood of adult-onset asthma

According to a new study from the Slone Epidemiology Center (SEC) at Boston University, African-American women who reported high levels of depressive symptoms had a greater likelihood of adult-onset asthma compared to women who reported fewer depressive symptoms.

The study, which currently appears online in the journal Annals of Allergy, Asthma & Immunology, was led by Patricia Coogan, DSc, senior epidemiologist at SEC and research professor of epidemiology at the Boston University School of Public Health.

This study followed 31,848 African-American women between 1999 and 2011, all of whom are participants in the Black Women's Health Study (BWHS) who completed health questionnaires every two years. In 1999 and 2005 they rated the frequency of experiencing 20 symptoms (e.g., "I felt depressed", I felt lonely", "I could not get going"). The 20 answers were summed into a scale ranging from zero (rarely or never experiencing depressive symptoms) to 60 (experiencing all depressive symptoms "most or all of the time"). The scale is commonly used in epidemiologic studies and a score of 16 has been used to identify individuals at high risk of depression.

The results indicated that as the frequency of depressive symptoms increased, the incidence of adult-onset asthma also rose, up to a two-fold increase in women in the highest category (score of ≥33) compared to the lowest category (score <16) of the depressive symptom scale. Furthermore, the incidence of asthma was increased 2.8 times in women who had a depressive symptom score of ≥16 and also reported use of antidepressants.

"Our results are consistent with positive findings from three previous studies of depressive symptoms and asthma incidence conducted in smaller and primarily white populations," said Coogan. "The hypothesized mechanism linking depressive symptoms to asthma incidence is depression-related stress and its physiological consequences, particularly effects on the immune system and the airways. Given the high prevalence of both asthma and of depression in women, the association is of public health importance," Coogan added.

The BWHS is the largest follow-up study of the health of African American women in the United States. Led by researchers at the Slone Epidemiology Center, the BWHS has followed 59,000 African-American women through biennial questionnaires since 1995 and has led to a better understanding of numerous health conditions that disproportionately affect African-American women.