*Univariate odds ratio (OR) not reported but calculated from the figures given; †pooled univariate OR using the Mantel-Haenszel estimate; ‡pooled adjusted OR using ln (effect size) and SE (ln (effect size)); §adjusted for infant age, gender, race, time of death, geographic location, season, sleeping position, birthweight, gestation, admission to special care baby unit, maternal age, attendance at antenatal class, maternal smoking, breastfeeding, marital status, parity, socio-economic status and occupation; ¶adjusted for gender, gestational age, parity, birthweight, sleeping position, routine co-sleeping, use of prescription drugs or illness in the previous week, usually found sweaty on waking, history of changing position during sleep, swaddling, tog value of bed covers, age of mattress, use of cot bumper, maternal age, whether breastfed, marital status, parental smoking, maternal schooling, deprivation score, social class and previous infant death.