Earlier type 1 onset, heavier lifetime risk: childhood diagnosis tripled mortality

Design

Retrospective nationwide cohort with matched population controls

Population

34,155 adults with type 1 diabetes and 150,026 controls, Sweden, 1998 to 2020

Primary outcome

All-cause, cardiovascular and non-cardiovascular mortality by age at onset

Effect

HR 0.98 (0.98 to 0.99) per later year of onset; onset age 0 to 10 vs controls HR 3.23 all-cause, 5.73 cardiovascular

A Swedish National Diabetes Register cohort followed 34,155 adults with type 1 diabetes and 150,026 matched population controls from 1998 to 2020, modelling risk per year of age at diagnosis.

Each later year of onset was associated with lower all-cause mortality (hazard ratio 0.98, 95% CI 0.98 to 0.99), about 8% lower per five years. The gradient was steeper for cardiovascular death (0.97 per year). Compared with controls, people diagnosed between birth and ten years had an all-cause mortality hazard of 3.23 and a cardiovascular mortality hazard of 5.73.

The practical reading is that duration of exposure matters. A young adult diagnosed in early childhood may already carry two decades of glycaemic exposure, and cardiovascular risk calculators built on age will understate it. This is observational, so it describes who is at risk rather than proving that delaying onset would help.

• Record age at diagnosis, not just current age, in every adult with type 1 diabetes.
• Consider earlier statin discussion in young adults diagnosed in early childhood.
• Do not rely on age-based cardiovascular risk scores in childhood-onset type 1 diabetes.
• Screen for kidney disease and retinopathy by diabetes duration as well as age.

Why it matters

A 30-year-old diagnosed at five is not cardiovascularly a 30-year-old, and age-based prevention thresholds miss that.

Don't overread it

This was a register association; it cannot show that delaying onset would lower risk.

The statistics, in plain English

A hazard ratio of 0.98 per year sounds tiny, but it compounds: over five years it adds up to about an 8% lower death rate. The hazard of 5.73 for cardiovascular death in childhood-onset disease means roughly five to six times the rate of matched people without diabetes. Both are associations adjusted for measured factors, not proof of cause.

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