Cohort profile: 1970 British Birth Cohort (BCS70).

The 1970 British Birth Cohort Study (BCS70) is an ongoing, multidisciplinary, longitudinal study. It takes as its subjects all those currently living in England, Scotland, and Wales who were born in a single week of 1970. To date there have been seven sweeps of the study, including the original birth survey. BCS70 began as the British Births Survey, when data was collected about the births and social circumstances of over 17 000 babies born in England, Scotland, Wales, and Northern Ireland. Data were collected using a questionnaire completed by the midwife who had been present at the birth and, in addition, information was extracted from clinical records. The original study was sponsored by the National Birthday Trust Fund in collaboration with the Royal College of Obstetricians and Gynaecologists, under the directorship of Roma and Geoffrey Chamberlain. The study aimed to examine the social and biological characteristics of the mother in relation to neonatal morbidity, and to compare the results with those of the 1958 National Child Development Study. When the cohort children were 3.5 yr the study transferred to the Department of Child Health at the University of Bristol where Neville Butler, Professor of Child Health, took over responsibility for the follow-ups at 5 and 10 yr, what came to be known as the Child Health and Education Study. In 1975 and 1980, parents of the children in the study were interviewed by health visitors, and information was gathered from the child’s class teacher and head teacher, from the school health service, and from the children themselves. Cohort members who were born in Northern Ireland were included in the birth survey but dropped from the study in all subsequent sweeps. The main findings on health from the 5 and 10 yr surveys are published in a report by the original team. 1