Effect of smoking in patients with ankylosing spondylitis: A cross-sectional study in state of Madhya Pradesh, India

Aim: Understanding the impact of smoking on the development and severity of ankylosing spondylitis (AS) is pivotal, as it affects the management of the disease. This study investigated the effect of smoking in patients with AS and its outcome on the disease. Methods: This was a cross-sectional study from September 1, 2018, to November 30, 2018, in a rheumatology outpatient department enrolled patients aged >18 years diagnosed with AS and divided into two groups according to their smoking status. Demographic details and hematological and biochemical parameters were noted. Modified Schober's test, chest expansion, and duration of disease measurements were performed. Disease activity and functional state were evaluated using the Bath AS Disease Activity Index (BASDAI) and Bath AS Functional Index (BASFI). Results: A total of 48 patients were enrolled (smoker, n = 20; nonsmoker, n = 28). The mean age in smoker and nonsmoker groups was 39.40 years and 26.18 years, respectively, and male preponderance was observed; the mean duration of disease was 42.90 months and 43.14 months, respectively. BASDAI and BASFI scores were significantly higher in the smoker group (5.08 and 4.51, respectively) as compared to nonsmoker group (3.40 and 2.34, respectively) (P < 0.001). The modified Schober's test showed a significant decrease in the range of spinal mobility in the smoker group (2.67 cm) than in the nonsmoker group (4.40 cm) (P < 0.001). A significant decrease in the mean chest expansion was seen in the smoker group than the nonsmoker group (3.08 vs. 5.68 cm; P < 0.001). Conclusion: Results demonstrate the negative effect of smoking on disease and functional activity in patients with AS.