The Cooper Institute
 

Founded in 1970 by the "Father of Aerobics"
Kenneth H. Cooper MD, MPH

 
 

Asthma and Depression: the Cooper Center Longitudinal Study (CCLS)

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Live well

Wednesday, May 02, 2018


Asthma and depression are common conditions among U.S. residents, with each affecting approximately 10% of the population.


When compared to those with asthma but without depression, those with asthma and depression have decreased work performance, increased days lost from work, a greater number of asthma-related emergency room visits, and worse health outcomes. Studies performed in countries outside of the United States have shown varying degrees of association between asthma and depression. In the U.S., the limited number of studies in this area have relied on patient self-reporting of asthma and depression rather than objective clinical measures of these conditions.

Accordingly, researchers from The Cooper Institute and colleagues from other medical organizations undertook a project to objectively examine the association between asthma and depression within a clinical setting. A total of 12,944 Cooper Clinic patients underwent comprehensive preventive medical exams between 2000 and 2012. Presence of asthma was documented via questionnaire, medication use, and various measurements of lung function. Current symptoms and severity of depression were measured by using the 10-item Center for Epidemiologic Studies Depression Scale (CES-D). This widely used instrument is scored on a 0-30 scale, with scores greater than or equal to 10 indicating significant depressive symptoms. Additional questions were used to identify a past history of depression.  

As is the case for most CCLS projects, the sample was predominantly white and college-educated. Approximately 9% of the sample had asthma. Patients with asthma were younger, less likely to smoke, and more likely to have hypertension, obesity, or diabetes than those without asthma.


 

After controlling for several variables that might ‘muddy the waters’ patients with asthma were 41% more likely to have current significant depressive symptoms as measured via the CES-D, than patients without asthma. Furthermore, patients with asthma were 66% more likely to have a past history of depression when compared to patients without asthma.


Previous studies performed outside of the U.S. showed that poor asthma control is a risk factor for depressive symptoms and decreased quality of life. However, the objective data collected in the current study revealed that most Cooper Clinic patients with asthma had a relatively mild form of the disease. Thus, the burden of their condition was relatively light. Additionally, because of their relatively high socioeconomic status, low income and poor access to health care would not contribute to the observed association between asthma and depression in this sample. The authors suggested that because asthma is often a pro-inflammatory state, this might be tied to symptoms of depression. They also suggested that common genetic factors might also explain the association between asthma and depression.         

In summary, a significant association was found between asthma and depression; this association remained after controlling for a number of other variables. When compared to individuals without asthma, individuals with asthma are more likely to have significant depressive symptoms. Two important conclusions stated by the authors were 1) There should be more extensive depression screening in people with asthma, and 2) Further research should be conducted to illuminate the underlying mechanism that links asthma and depression.

Reference
Trojan, T., Khan, D., DeFina, L., Akpotaire, O., Goodwin,R., and Brown, S. (2014). Asthma and depression: the Cooper Center Longitudinal Study. Annals of Allergy, Asthma, and Immunology,112:432-436.