Coffee consumption and the risk of latent autoimmune diabetes in adults-results from a Swedish case-control study

Aims Coffee consumption is associated with a reduced risk of Type2 diabetes. Our aim was to investigate if coffee intake may also reduce the risk of latent autoimmune diabetes in adults, an autoimmune form of diabetes with features of Type2 diabetes. Methods We used data from a population-based case-control study with incident cases of adult onset (35years) diabetes, including 245 cases of latent autoimmune diabetes in adults (glutamic acid decarboxylase antibody positive), 759 cases of Type2 diabetes (glutamic acid decarboxylase antibody negative), together with 990 control subjects without diabetes, randomly selected from the population. Using questionnaire information on coffee consumption, we estimated the odds ratio of latent autoimmune diabetes in adults and Type2 diabetes adjusted for age, sex, BMI, smoking, physical activity, alcohol, education and family history of diabetes. Results Coffee intake was inversely associated with Type2 diabetes (odds ratio0.92, 95%CI 0.87-0.98 per cup/day). With regard to latent autoimmune diabetes in adults, the general trend was weak (odds ratio1.04, 95%CI 0.96-1.13), but stratification by degree of autoimmunity (median glutamic acid decarboxylase antibody levels) suggested that coffee intake may be associated with an increased risk of high glutamic acid decarboxylase antibody latent autoimmune diabetes in adults (odds ratio1.11, 95%CI 1.00-1.23 per cup/day). Furthermore, for every additional cup of coffee consumed per day, there was a 15.2% (P=0.0268) increase in glutamic acid decarboxylase antibody levels. Conclusions Our findings confirm that coffee consumption is associated with a reduced risk of Type2 diabetes. Interestingly, the findings suggest that coffee may be associated with development of autoimmunity and possibly an increased risk of more Type1-like latent autoimmune diabetes in adults.