The MRC National Survey of Health and Development (NSHD) has informed UK health care, education and social policy for more than 50 years and is the oldest and longest running of the British birth cohort studies. Today, with study members in their seventies, the NSHD offers a unique opportunity to explore the long-term biological and social processes of ageing and how ageing is affected by factors acting across the whole of life. From an initial maternity survey of 5362 births recorded in England, Scotland and Wales during one week of March 1946, a socially stratified sample of singleton babies born to married parents was selected for follow-up. These participants have been studied over twenty times throughout their life. During their childhood, the main aim of the NSHD was to investigate how the environment at home and at school affected physical and mental development and educational attainment. During adulthood, the main aim was to investigate how childhood health and development and lifetime social circumstances affected their adult health and function and their change with age. Now, as participants have reached retirement, the research team is developing the NSHD into a life course study of ageing.
Study members were asked to provide a peripheral blood and buccal sample at a home visit at age 53. Using both blood and buccal samples at age 53, a subset of women were selected to be analysed using the Illumina 450k array (>480,000 CpG sites). Buccal DNA methylation: 790 women were selected from those who provided both a peripheral blood and a buccal cell sample at the age of 53 years in 1999, who had not previously developed any cancer and who had complete information on epidemiological variables of interest and follow-up. Blood DNA methylation: Matched blood samples were analysed from 152 women - 75 had developed cancer after age 53 years and 77 controls.