Overweight and obesity in type 1 diabetes equal those of the general population

The obesity epidemic might affect patients with type 1 diabetes (T1DM), historically described as lean and insulin-sensitive subjects. Insulin resistance in T1DM might increase diabetic complications, especially cardiovascular disease. Therefore, the body mass index (BMI) in T1DM patients was analyzed in comparison to the general population. Furthermore, the impact of increased BMI on glycemic control and metabolic alterations was assessed.

Body mass index was compared overall and among four different age groups between adult T1DM (n = 186), treated in the outpatient clinic between 2014 and 2016, and 15,771 individuals from the general population who took part at an Austrian health survey. Furthermore, parameters of glycemic control, lipid state, blood pressure and additional medication were compared between T1DM with a BMI under or above 27.5 kg/m².

Patients with T1DM had significantly higher BMI values than general population (25.9 ± 4.2 kg/m² vs. 25.3 ± 4.5 kg/m²; p = 0.027), controlling for age group; however, prevalence of overweight (39.8% vs. 33.1%) and obesity (14% vs. 13.8%) was not significantly different. Within the 4 age groups only T1DM patients between 30 years and 49 years old had significantly higher BMI values compared to the general population (mean difference 1.9 kg/m²; 95% confidence interval, CI: 0.96-2.83 kg/m²). In T1DM, a BMI ≥27.5 kg/m² was associated with increased rates of hypertension, dyslipidemia, microalbuminuria, and increased insulin demand, whereas glycemic control was not affected.

In contrast to common descriptions T1DM patients have a higher BMI compared to the general population. Rates of overweight and obesity in T1DM equal those of the general population. Therefore, it is concluded that the obesity epidemic has reached T1DM patients and "double diabetes" might be an entity to consider.