Plateau of adiposity in Australian children diagnosed with Type 1 diabetes: a 20-year study.

AIMS: To examine temporal trends in anthropometry in children with Type 1 diabetes from Sydney, Australia. METHODS: We conducted a retrospective study in a total of 1975 children with Type 1 diabetes, aged <16 years, between 1990 and 2009. Trends in height, weight and BMI standard deviation score after initial stabilization were examined by age group (<5 years, 5 to <10 years, 10 to 16 years) and time period of diagnosis (T1: 1990-1994, T2: 1995-1999; T3: 2000-2004 and T4: 2005-2009). Factors associated with BMI standard deviation score (time period, age group, gender and socio-economic status) were examined using multivariable linear regression. RESULTS: The mean BMI standard deviation score (±sd) increased between T1 and T2 (0.54 ± 1.14 vs 0.81 ± 1.14, P = 0.002), but remained steady thereafter (T3: 0.85 ± 1.11, T4: 0.87 ± 1.09; T2 to T4: P = 0.40). Similarly, the prevalence of overweight and obesity increased from T1 to T2 (26 to 35%, P = 0.01), but was unchanged thereafter (T3: 34%, T4: 34%; T2 to T4: P = 0.90). On multivariable regression analysis, a higher BMI standard deviation score was associated with younger age (≥5 years vs <5 years, ß=-0.40, 95% CI -0.51 to -0.28, P < 0.001), later time period (T2 to T4 vs T1, ß=0.30, 95% CI 0.16-0.45, P < 0.001) and male gender (ß=0.25, 95% CI 0.15-0.34, P < 0.001). CONCLUSION: The prevalence of overweight and obesity has remained unchanged in children at diagnosis of Type 1 diabetes over 15 years. These findings suggest that higher adiposity alone cannot account for the continued rising incidence of Type 1 diabetes in recent years.