Introduction: T1D is historically associated with reduced body mass index (BMI) due to the catabolic state of insulin deficiency.  However, increasing levels of obesity have been reported[1]. This results in combined insulin deficiency and resistance, which is associated with poorer glycaemic control and earlier progression of complications[2].

Hypothesis: Prevalence of overweight-obesity is higher in young adults with T1D than an age-matched population. 

Methods: Retrospective chart review of patients with T1D attending a regional tertiary Young Adults Diabetes Clinic 2013-2014.  Data is presented as mean±standard deviation unless specified.  BMI was calculated on mean clinic weight 2013-2014.    

Results: 301/320 patients had BMI data available, with age 24±3.6 years, age at diagnosis of diabetes 13±6.5 years, and duration of disease 10.7±6.3 years.  Mean HbA1c was 8.6±1.9%.  26% of patients utilised subcutaneous insulin pumps.  

33% of T1D patients had BMI in the overweight range (25-29.9kg/m²), and 21% were obese (>30kg/m²).  When compared to Australian data (AUS)[3] for young adults aged 18-25, 47% of corresponding T1D had BMI >25 kg/m², compared to 36% of AUS (p<0.01); in the 25-34 age bracket, 63% of T1D had BMI >25kg/m² compared to 55% of AUS (p=0.05).  Stratified by sex, females with T1D were more likely to be overweight or obese than AUS data (52% vs 38%, p<0.001).  This difference was not seen in men.   There was no correlation between BMI and HbA1c or pump use, although obese patients had longer duration of disease than normal BMI (12.1 vs 10.4yrs, p=0.05).  The proportion of overweight and obesity was unchanged between first clinic attendance and 2013/2014. 

Conclusions: Young adults with T1D have increased rates of overweight-obesity compared with age matched controls.  The association is stronger in women and is evident at transition to adult care. Specific interventions are needed to normalise body weight to minimise health consequences of obesity.