Risk factors for microvascular complications in childhood-onset type 1 diabetes: impact of perinatal factors, age at onset and glycemic control over more than 30 years of follow-up

AIMS: To examine impact of perinatal factors, age at diabetes onset, and glycaemic control on development of microvascular complications in childhood-onset type 1 diabetes (T1D) over 30 years of follow-up. METHODS: 94 individuals diagnosed with T1D at 0-14 years in Sweden (1981-1992). Follow-up through March 2022 via national registers. Outcomes were diabetic retinopathy (DR), proliferative DR (PDR), and diabetic nephropathy (DN), assessed as albuminuria and macroalbuminuria. Cox proportional hazards, Poisson regression, and mixed-effects models were applied. Age at onset was stratified as prepubertal or pubertal. RESULTS: Median follow-up was 33 years (range 9-40). 85% developed DR, 19% PDR, 45% albuminuria and 12% macroalbuminuria. Higher HbA1c predicted albuminuria (HR 1.02), DR (HR 1.02), and PDR (HR 1.05). Prior DR was associated with albuminuria (HR 2.07) and prior albuminuria with DR (HR 1.74). Female sex predicted PDR (HR 3.28). Poisson models showed that age predicted albuminuria, whereas diabetes duration predicted DR. Diastolic blood pressure (BP) predicted albuminuria (HR 1.07) and smoking macroalbuminuria (HR 4.81). Both systolic (HR 1.03) and diastolic BP (HR 1.08) predicted DR. Perinatal factors were not associated with any of the outcomes. CONCLUSIONS: During more than 30 years of follow-up microvascular complications were frequent although severe outcomes were infrequent. diabetic retinopathy (DR) and nephropathy (DN) had differential temporal patterns of development and known modifiable risk factors are important.