Objectives: The aim was to examine trends in the proportion of smoking in diabetes patients, and to study associations between smoking, glycaemic control, and microalbuminuria.
Methods: Smoking habits were reported to the Swedish National Diabetes Register (NDR), with data from hospitals and primary health care. Patient characteristics included were age, gender, type of treatment, diabetes duration, HbA1c, BMI, blood pressure, antihypertensive and lipid-lowering drugs, and microalbuminuria.
Results: The proportion of smokers in type 1 diabetes was 12-15% during 1996-2001, it was high in females<30 years (12-16%), and was higher in the age group 30-59 years (13-17%) than in older (6-9%) patients. The corresponding proportion of smoking in type 2 diabetes was 10-12%, higher in those less than 60 years of age (17-22%) than in older (7-9%) patients. Smoking type 1 and type 2 patients in 2001 had higher mean HbA1c but lower mean BMI values than non-smokers. Smokers also had higher frequencies of microalbuminuria, in both type 1 (18 vs 14%) and type 2 (20% vs 13%) diabetes. Multiple logistic regression analyses disclosed that smoking was independently associated with elevated HbA1c levels (p<0.001) and microalbuminuria (p<0.001), but negatively with BMI (p<0.001), in both type 1 and type 2 diabetes.
Conclusions: Smoking in patients with diabetes was widespread, especially in young female type 1, and in middle-aged type 1 and type 2 diabetes patients, and should be the target for smoking cessation campaigns. Smoking was associated with both poor glycaemic control and microalbuminuria, independently of other study characteristics.