The Effect of Smoking on Some Microvascular Complications in Type 2 Diabetics

Abstract

Background Smoking is associated with increased risk and enhances progression of chronic diabetes related complications like nephropathy and retinopathy. Objective This study was designed to assess the effect of smoking on the development of some chronic diabetes related complications namely nephropathy and retinopathy. Methods This is a cross sectional study that enrolled 100 patients with diabetes mellitus, 50 patients were smokers and the other 50 patients were non-smokers. The patients had been randomly selected from those who had attended the National Diabetes Center-Baghdad/Iraq during the period between the 1st of January 2004, to the 1st of June 2004. All of the patients have been asked for their history of smoking by a questionnaire form and they had been examined and investigated to assess their glycaemic control and diagnosing any chronic diabetic complication that might be present. Statistical analysis had been done using Chi square test and P<0.05 is considered significant. Results This study revealed male to female ratio of 6:1, 66% of patients were 40-59 year-old, 70% had diabetes for less than 15 years, 92% had smoked for 10 years or longer time, 60% smoked more than 1 pack (20 cigarettes) per day, the male :female ratio ,age range of patients and duration of diabetes in the non-smoker group were almost identical to smoker diabetics .84% of smoker diabetics had HbA1c level of 7.0% or more, while 64% of non-smoker diabetics had HbA1c >=7.0%. 88% of non-smoker diabetics had abnormal BMI (being overweight, obese, and morbidly obese) compared to only 62% of smoker diabetics with abnormal BMI . 50% of smoker diabetics had positive Micral test for micro albuminuria, while only 28% of non-smoker diabetics had positive Micral test. 60% and 34% of smoker and non-smoker diabetics respectively had evidence of retinopathy in its different stages. Statistical analysis revealed significant association between being smoker diabetic and poorer glycaemic control (P<0.05), occurrence of microalbuminurea (P<0.05) and development of diabetic retinopathy (P<0.05). Conclusions This study indicated that smoking significantly enhances the development of chronic diabetes related complications namely nephropathy and retinopathy. In order to reach strict or near strict glycaemic control which is the corner stone in primary as well as secondary prevention of chronic diabetes related complications, smoking cessation must be encouraged to get better and longer life for diabetics.