This study investigated the relationship between the development of diabetic retinopathy and pubertal status at onset of diabetes in 521 Type 1 diabetic patients diagnosed between 1950 and 1985. Pubertal status was based on age at onset (girls > or = 11 years and boys > or = 12 years). Retinopathy (all forms) developed in 112 patients (21.5%; 65 background and 47 proliferative retinopathy). For subjects diagnosed in either the prepubertal or postpubertal period, a similar proportion survived without developing retinopathy for any given duration of diabetes (chi 2 = 0.3822, p = 0.54). However, if only the postpubertal duration of diabetes is considered, then the proportion of patients surviving without retinopathy was significantly less for those diagnosed in the prepubertal period (chi 2 = 14.2, p = 0.002). This study suggests that the prepubertal duration of diabetes is an important phase and that the years prior to puberty do contribute to the risk of developing microvascular injury.