Table 1

Characteristics of patients with idiopathic inflammatory myopathies (IIMs) and individuals without IIM*

Patients with IIM (n=1620)Individuals without IIM (n=7797)
Women, n (%)951 (59)4639 (60)
Birth year, median (Q1–Q3)1949 (1941–1964)1949 (1941–1964)
Living in Southern Sweden, n (%)1342 (83)6455 (83)
Age at inclusion, median (Q1–Q3)57 (44–66)57 (44–65)
IIM subtypes, n (%)
 Juvenile IIM†128 (8)
 Dermatomyositis‡501 (31)
 Other IIM§991 (61)
  • *Q1: the first quartile; Q3: the third quartile.

  • †Age at diagnosis ≤18 years of age.

  • ‡With diagnostic code M33.1 and age at diagnosis >18 years of age.

  • §With diagnostic code M33.2, M33.9 or G72.4 and age at diagnosis >18 years of age.