Asthma is an independent risk for elevation of plasma C-reactive protein levels

Chronic inflammation of the airways plays a major role in the pathogenesis of asthma. Although C-reactive protein (CRP) is now an established circulating marker for cardiovascular diseases, it remains unclear whether asthma is an independent risk for increased plasma CRP.

In Study 1, we evaluated CRP levels in 329 asthmatic patients and 1684 non-asthmatic subjects. Inhaled corticosteroids were regularly used by 308 asthmatics. In Study 2, the effects of inhaled corticosteroids on CRP levels were examined in 64 corticosteroid-naive asthmatic patients.

In Study 1, plasma CRP levels were associated with body mass index (R=0.349, P<0.0001) and age (R=0.111, P<0.0001) in all study subjects, but were higher in patients with asthma, hypertension, diabetes and/or dyslipidemia than in those without these disorders. Multivariate regression analysis identified body mass index, age and asthma, but not hypertension, diabetes or dyslipidemia, as independently associated with an elevation of CRP levels. In Study 2, treatment of 64 corticosteroid-naive asthmatic patients with inhaled corticosteroids for 3 months significantly reduced plasma CRP levels.

Asthma is a disorder associated with increased plasma CRP levels independent of various other factors. Treatment with inhaled corticosteroids was associated with a significant reduction in plasma CRP levels, which may reflect their clinical effect on the inflammatory process within airways.