An Inverse Relationship Between Age of Type 2 Diabetes Onset and Complication Risk and Mortality: The Impact of Youth-Onset Type 2 Diabetes

OBJECTIVE This study compared the prevalence of complications in 354 patients with T2DM diagnosed between 15 and 30 years of age (T2DM(15-30)) with that in a duration-matched cohort of 1,062 patients diagnosed between 40 and 50 years (T2DM(40-50)). It also examined standardized mortality ratios (SMRs) according to diabetes age of onset in 15,238 patients covering a wider age-of-onset range. RESEARCH DESIGN AND METHODS Complication status was assessed according to a standard protocol and extracted from our electronic database. Survival status was ascertained by data linkage with the Australian National Death Index. SMRs were calculated in comparison with the background Australian population and analyzed according to age of onset. RESULTS After matching for duration, despite their younger age, T2DM(15-30) had more severe albuminuria (P = 0.004) and neuropathy scores (P = 0.003). T2DM(15-30) were as commonly affected by metabolic syndrome factors as T2DM(40-50) but less frequently treated for hypertension and dyslipidemia (P < 0.0001). An inverse relationship between age of diabetes onset and SMR was seen, which was the highest for T2DM(15-30) (3.4 [95% CI 2.7-4.2]). SMR plots adjusting for duration show that for those with T2DM(15-30), SMR is the highest at any chronological age, with a peak SMR of more than 6 in early midlife. In contrast, mortality for older-onset groups approximates that of the background population. CONCLUSIONS The negative effect of diabetes on morbidity and mortality is greatest for those diagnosed at a young age compared with T2DM of usual onset. These results highlight the growing imperative to direct attention toward young-onset T2DM and for effective interventions to be applied before middle age.