Table 2.

Mean Number of First- or Second-Degree Family Members With Autoimmune Disorders per Family and Number of Families in Each Group With a Specific Autoimmune Disorder*

PDDAutoimmuneHealthy
Mean Number per Family1.87 ± 1.61.44 ± 1.5§0.93 ± 1.1
Hypothyroidism/ Hashimoto’s thyroiditis361114
Rheumatic fever23#106
Multiple sclerosis721
  • * Each group consists of 101 families.

  • Compared with autoimmune: t = 2.03; P = .03.

  • Compared with healthy: t = 4.90; P = .000003.

  • § Compared with healthy: t = 2.72; P = .01.

  • Compared with autoimmune: χ2 = 18.06; P = .00002.

  • Compared with healthy: χ2 = 13.21; P = .0003.

  • # Compared with healthy: χ2 = 12.31; P = .0005.