- Design
- Nationwide register-based matched cohort
- Population
- 2,932 adults with JIA vs 29,097 matched comparators, Norway
- Primary outcome
- 5-year comorbidity prevalence and all-cause mortality
- Effect
- Mortality 2.4 vs 1.8 per 1,000 person-years; hypertension 3.6% vs 1.4%
This Norwegian register study, published 15 September in Rheumatology, matched 2,932 adults with juvenile idiopathic arthritis seen in specialist care between 2009 and 2024 to 29,097 general-population comparators by age, sex and county.
Adults with JIA had higher prevalence of hypertension (3.6% vs 1.4%), ischaemic heart disease without infarction (1.0% vs 0.6%), chronic kidney disease (0.5% vs 0.2%), type 1 diabetes (1.7% vs 0.7%), coeliac disease (1.4% vs 0.7%), autoimmune thyroiditis and alopecia. All-cause mortality was higher (2.4 vs 1.8 per 1,000 person-years). Comorbidity and mortality were similar whether or not patients had recent DMARD exposure.
JIA does not stay in childhood. The transition to adult care is the point to start cardiovascular and autoimmune screening, which paediatric follow-up often does not include.
- Check blood pressure at every visit for adults with JIA.
- Screen adults with JIA for coeliac and thyroid disease if symptoms suggest it.
- Assess cardiovascular risk from the time of transition to adult care.
- Recent DMARD use was not associated with the excess comorbidity.
Why it matters
Challenges the idea that JIA is a childhood disease with no adult consequences beyond the joints.
Don't overread it
Register prevalence from coded diagnoses; it cannot show JIA or its treatment caused the comorbidities.
The statistics, in plain English
Absolute differences are small — for example, 3.6% versus 1.4% for hypertension — but they appear in young adults who should have very low rates.
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