摘要：To examine th. h.poth.sis th.t bedsh.ring with.an infant is associated with.an increased risk of sudden infant death.syndrome (SIDS). Study design: A 1:2, case:control study in Scotland UK, population 5.1 million, including 123 infants wh. died of SIDS between January 1, 1996 and May 31, 2000, and 263 controls. Th. main outcome measure was sh.ring a sleep surface during last sleep. Results: Sh.ring a sleep surface was associated with.SIDS (multivariate OR 2.89, 95% CI 1.40, 5.97). Th. largest risk was associated with.couch.sh.ring (OR 66.9, 95% CI 2.8, 1597). Of 46 SIDS infants wh. bedsh.red during th.ir last sleep, 40 (87% ) were found in th. parents’ bed. Sh.ring a bed wh.n <11 weeks (OR 10.20, 95% CI 2.99, 34.8) was associated with.a greater risk, P = .010, compared with.sh.ring wh.n older (OR 1.07, 95% CI 0.32, 3.56). Th. association remained if moth.r did not smoke (OR8.01, 95% CI 1.20, 53.3) or th. infant was breastfed (OR 13.10, 95% CI 1.29, 133). Conclusions: Bedsh.ring is associated with.an increased risk of SIDS for infants <11 weeks of age. Sh.ring a couch.for sleep sh.uld be strongly discouraged at any age.