Current Smoking—An Independent Predictor of Elevated A1C in Adults with Type 2 Diabetes

While the cardiovascular risk of smoking is well documented in persons with type 2 diabetes (T2D), less is known about the impact of smoking on glycemic control in this population. The purpose of this study was to determine predictors, including smoking status, of elevated A1C in a sample of adults with T2D. This secondary analysis used baseline data from adults (N=256; 48% male) recruited for the Diabetes Sleep Treatment Trial. Participants were queried on demographics, diabetes-related distress (Problem Areas in Diabetes), diabetes knowledge (Diabetes Knowledge Test), and smoking behavior (never/former/current). A clinical assessment obtained height and weight to calculate BMI (kg/m²) and A1C. Non-smokers (53%; n=136) and former smokers (28%; n=72) were similar (p ≥.05) in terms of age, A1C, BMI, diabetes-related distress and knowledge; however, current smokers (19%; n=48) were less obese (BMI 33.3 [SD 6.5] vs. 36.1 [SD 6.9] kg/m², p=.016), more likely to be non-Caucasian, have lower education, more financial difficulty, higher diabetes-related distress, and lower diabetes knowledge than non-smokers (all p-values <.05). Using hierarchical regression diabetes duration, diabetes distress, and current smoking status were identified as predictors of higher A1C. We conclude smoking is associated with lower BMI and higher A1C, providing further support for counseling for smoking cessation in adults with T2D.