Gluten intake and risk of thyroid peroxidase autoantibodies in the Diabetes Autoimmunity Study In the Young (DAISY).

Purpose Autoimmune diseases co-occur, perhaps due to common risk factors. The age at gluten introduction and gluten intake in early childhood has been associated with the autoimmunity preceding celiac disease (CD) and type-1 diabetes (T1D). We explored their associations with the development of thyroid autoimmunity. Methods DAISY has prospectively followed children at increased risk for T1D and CD since 1993. During follow-up, 107 children developed thyroid autoimmunity, defined as positivity for autoantibodies against thyroid peroxidase on at least two study visits. Age at gluten introduction was ascertained from food history interviews every 3 months until 15 months of age. Gluten intake (g/day) at age 1-2 years was estimated using a food frequency questionnaire. Results From multivariable Cox regression, there was no association between the age of gluten introduction nor the amount of gluten intake and development of thyroid autoimmunity. However, females (hazard ratio = 2.19, 95% CI: 1.46, 3.27) and cases of islet autoimmunity (HR = 2.20, 95% CI: 1.39, 3.50) were significantly more likely to develop thyroid autoimmunity, while exposure to environmental tobacco smoke decreased the risk (HR = 0.46, 95% CI: 0.30, 0.71). Conclusions Neither the age of gluten introduction nor the amount of gluten consumed in early childhood is associated with risk of thyroid autoimmunity.