Additional analyses of very large population-based studies, primarily conducted in Scandinavian countries and Taiwan, support the estimates from the family studies [7–12]. In line with the studies that did meet our inclusion criteria, the risk for OCD in these population-based studies varied from 4.7 [7] to 7.64 [12] for parents, 4.82 [11] to 8.95 [12] for full siblings, and 4.54 [8] to 8.95 [12] for the offspring. Because these population studies had superior statistical power and less risk of selection bias, we conclude that the familial risk estimates are generalizable to the general population.
