The percentages of survivors and siblings with self-reported performance limitations or participation restrictions and the standardized RRs adjusted for age, sex, and intrafamily correlation with 95% CIs are shown in Table 2. After adjustment for age and sex, survivors (19.6%) were nearly twice as likely to report performance limitations when compared with siblings (11.8%) (RR, 1.8 [CI, 1.7 to 2.0]). When evaluated as a continuous variable, after adjustment for age and sex, mean physical performance score also differed between survivors (mean, 16.6 [SD, 2.8]) and siblings (mean, 17.2 [SD, 2.1]) (P < 0.001). Participation restrictions were less common than performance restrictions among survivors (range, 2.9% to 7.9%) and siblings (range, 0.5% to 1.5%); however, survivors were 4.7 times (CI, 3.0 to 7.2 times) more likely than siblings to report restricted abilities to perform personal care or routine activities like shopping or housework (RR, 4.7 [CI, 3.6 to 6.2]). Survivors were 5.9 times (CI, 4.5 to 7.6 times) more likely to report that poor health prevented them from attending school or work compared with siblings. Similar to findings in our overall analysis, a matched analysis that included only those survivors with complete data who had a sibling in the comparison group yielded RRs of 1.6 (CI, 1.4 to 1.9) for performance limitations, 5.2 (CI, 2.8 to 9.5) for restricted personal care skills, 4.0 (CI, 2.7 to 5.9) for restricted routine activities, and 5.2 (CI, 3.5 to 7.7) for poor health preventing school or work attendance.