Severe Hypoglycemia and Smoking in a Long-Term Type 1 Diabetic Population

OBJECTIVE: The purpose of this study was to evaluate the relationship of severe hypoglycemia and smoking in a population-based cohort of individuals with long-term type 1 diabetes. RESEARCH DESIGN AND METHODS: This was a cross-sectional analysis of the population-based cohort of the Wisconsin Epidemiologic Study of Diabetic Retinopathy. The analyses in this report were limited to 537 type 1 diabetic individuals with complete data who participated in the last examination phase (2000-2001). Severe hypoglycemia was defined as having one or more episodes of loss of consciousness or overnight hospitalization attributable to hypoglycemia in a 1-year period before the examination. RESULTS: The prevalence of severe hypoglycemia in this population was 14.3%. In univariate analysis, current smokers had a greater chance of having severe hypoglycemia compared with never smokers (odds ratio 2.40 95% CI 1.30-4.40). When we controlled for relevant confounders such as age, sex, A1C, waist-to-hip ratio, orthostatic hypotension, alcohol consumption, intensive insulin treatment, past history of severe hypoglycemia, and late complications of diabetes (nephropathy, neuropathy, and retinopathy), the association remained statistically significant, with current smoking presenting approximately 2.6 times greater odds of developing severe hypoglycemia. CONCLUSIONS: Current smokers with type 1 diabetes have higher odds of severe hypoglycemia episodes.