Pulmonary Function Test is More Restrictive in a smoker Patients with Ankylosing Spondylitis than in Non Smokers and is Associated with Impaired Spinal Mobility

Background:Ankylosing Spondylitis (AS) is a chronic, systemic, inflammatory, rheumatic disease affecting mainly the axial skeleton, with extra-skeletal manifestations, involving lung and an increased risk of cardiovascular morbidity. This research aims to assess the effect of smoking on pulmonary function test and spinal mobility.

Patients and Method:A cross sectional study was conducted on 150 AS patients. Information concerning smoking history, demographic and clinical data were collected. All patients were investigated for HLA-B27, complete blood count, chest x ray and pulmonary function test. AS metrology index (ASMI) measured depending five measurements.

Results:A total of 150 patients with AS were enrolled in this study (139 male and 11 female) with a mean age 36.7+/-8.2 years and mean duration of the disease 11.6+/-6.9 years. The mean FVC and FEV1 was highest among non-smokers and decrease increasing amount of smoking to reach its lowest mean among those with current high grade smoker but failed to reach the level of statistical significance. Smoking habit and age had a statistically significant association with mean of ASMI after adjusting for HLA-B27 status, gender, BMI and duration of the disease. Being a former smoker or low grade smoker is equally expected to increase ASMI by a mean of 0.85 compared to non-smokers.

Conclusion:Smoker AS patients had worse spinal mobility and restrictive PFT.