102 centenarians (10 men, 92 women) in eastern Massachusetts, 77 controls (28 men, 49 women) born in 1896 but died age 73

centenarians had 456 sibs (233 men, 223 women), controls had 240 sibs (121 men, 119 women)

RR higher after age 70

For any age after 65, siblings of centenarians had a 42·4% lower hazard of death (95% CI 0·334–0·538, p<0·0005).