Mortality from birth to adult life: a longitudinal study of twins

We have examined mortality from birth through adult life in a cohort of 256 2 twins born in Birmingham, UK, between 1950 and 1954. Their birthweights a nd obstetric details had been recorded as part of a longitudinal study of b irths in Birmingham. There were a total of 151 perinatal deaths (perinatal mortality rate = 116 per 1000 births) and 227 infant deaths (infant mortali ty rate = 94 per 1000 live births). 70 deaths occurred after the age of one year. In comparison with national mortality rates in the UK, overall morta lity in the twins was high (standard mortality rate, SMR = 259, 95% CI 221- 300). Mortality was highest in the first year of life and, although it then declined progressively, it remained significantly higher that that of the general population until age 5 years. The excess mortality was largely due to conditions originating in the perinatal period but there were excess rat es of congenital abnormalities, diseases of the respiratory system, digesti ve system and nervous and sensory organs. A Cox proportional Hazards analys is showed that the risk of death was related to low birthweight, prematurit y and male sex. Death of the co-twin was highly predictive of mortality thr oughout the period of follow up. These studies not only underline the exces s mortality associated with twin birth but show for the first time that thi s excess mortality extends into childhood. (C) 1998 Elsevier Science Irelan d Ltd. All rights reserved.