TABLE 3

Relative risk of sarcoidosis associated with having relatives with the disease

Cases exposedControls exposedRelative risk (95% CI)
First-degree relatives
 ≥1 relative#831/20 332 (4.1)1907/164 628 (1.2)3.73 (3.43–4.06)
 ≥2 relatives#28/20 332 (0.1)49/164 628 (<0.1)4.69 (2.93–7.51)
 Parents271/28 835 (0.9)638/245 054 (0.3)3.68 (3.23–4.19)
 Full siblings330/24 104 (1.4)696/203 989 (0.3)4.08 (3.45–4.83)
 Offspring262/33 197 (0.8)623/264 665 (0.2)3.23 (2.78–3.76)
Second-degree relatives
 Half siblings44/7511 (0.6)49/15 202 (0.3)1.50 (0.98–2.30)

Data are presented as n/N (%), unless otherwise stated. The confidence intervals were adjusted for autocorrelation arising from family clustering using robust estimates of the variance. #: for these analyses, an indicator for having more than one or two first-degree relatives with sarcoidosis was created for each case and control; : for these analyses, each proband–relative relationship contributed a unique observation in the dataset.