Cigarette smoking and structural brain deficits in patients with atrial fibrillation

Abstract Background Brain lesions are common in patients with atrial fibrillation (AF). Whether cigarette smoking is associated with an increased risk of brain lesions and reduced brain volume in patients with AF is currently unknown. Purpose In this analysis, we aimed to investigate the association of cigarette smoking habits with cerebral small vessel disease and overall brain volume. Methods For this cross-sectional analysis, we included AF patients from a multicentre cohort study. Smoking habits were defined by smoking status categories (never, former, current), duration (tertiles of years), cigarettes per day (CPD as obtained at baseline), packyears (PKY, tertiles) and time since smoking cessation (≤5 years, 6-10 years, 11-15 and ≥16 years). A standardized brain magnetic resonance imaging was done to assess the prevalence of small vessel disease white matter lesions (WML, graded according to the Fazekas scale) and small non-cortical infarcts (SNCI). Additionally, MRI was used to quantify the volumes of WML and SNCI; as well as to measure grey matter (GM) and white matter (WM) brain volumes. Multivariable adjusted logistic and linear regression analyses were applied. Results 1746 patients were enrolled (mean age 72.6 years, 27.5% females). 131 (7.5%) were current smokers, 846 (48.5%) former and 769 (44%) never smokers. Patients with a longer smoking duration, higher amount of CPD and PKY had reduced GM brain volume (p for linear trend 0.05, 0.005 and 0.02, respectively). Patient with higher CPD also had a reduced WM brain volume (p for linear trend 0.04). Compared to patients with a smoking duration in the lowest tertile (≤18 years), patients who had smoked for 19-34 years (second tertile) and more than 35 years (third tertile) had a higher risk for WML Fazekas ≥2 with an OR (95% CI) of 1.85 (1.29; 2.66, p=0.001) and 1.46 (1.01; 2.09, p=0.04) (Figure 1). Additionally, increasing smoking duration tertiles exhibited larger WML volumes, with a significant linear trend (p=0.05). AF patients who quit smoking ≥16 years ago had a lower odds for SNCI (OR 0.47 (0.24; 0.94, p= 0.03), less WML volume (β: -0.451 (-0.8; -0.11, p=0.01), and a higher WM brain volume (β: 16.9 (0.3; 33.6, p= 0.05) compared to patients who quit 5 years prior to the study enrolment (Figure 2). We found no significant difference in any structural brain deficit between current and former smokers compared to never smokers. Conclusion In a large AF population, we found that smoking duration and amount were associated with the loss of brain volumes. Smoking duration and time since smoking cessation were associated with small vessel disease.