The impact of asthma control on salivary cortisol level in adult asthmatics

Abstract

Asthma is a chronic disease causing psychological stress which leads to the

activation of hypothalamus-pituitary-adrenal axis. The purpose of this study is

to compare morning salivary cortisol levels in persistent asthma patients

according to their disease severities and control status. Total 206 adult asthma

patients were recruited from four university hospitals. Spirometry, questionnaire

of Asthma Quality of Life (AQOL) and Asthma Control Test (ACT) were completed,

and saliva samples were collected prospectively to measure morning cortisol

level. The mean patient age was 56.5+/-15.3 years with mean asthma duration of

9.1+/-11.1 years. Sixty five patents (31.6%) were classified as mild persistent

asthma, and 141 patients (68.4%) were classified as moderate persistent asthma

according to the Expert Panel Report 3. The mean predicted FEV1 was

88.8%+/-18.4%, and the methacholine PC20 was 9.6+/-8.5 mg/mL in all study

population. The mean ACT score for all patients was 19.9+/-3.6, and there were 71

(34.5%) patients in poorly controlled and 135 (65.5%) in well controlled asthma.

The poorly controlled asthma patients were characterized by significantly lower

FEV1 (84.6%+/-17.6% vs 91.1%+/-18.5%, P=0.018), lower AQOL scores (46.0+/-13.9 vs

73.8+/-26.3, P<0.001), and lower salivary cortisol levels (0.14+/-0.08 vs

0.18+/-0.11 microg/dL, P=0.04) compared to well controlled asthma. The ACT score

was significantly related to salivary cortisol levels (P=0.034) after adjusting

for age. There was no significant difference in salivary cortisol levels

(0.17+/-0.12 vs 0.16+/-0.08, P=0.725) when analyzed according to the dose of used

corticosteroid and lung function. Asthma control status affects morning salivary

cortisol level. Measuring the morning salivary cortisol level might be a simple

and new way to assess asthma control status.