The Lothian Birth Cohort 1936: a study to examine influences on cognitive ageing from age 11 to age 70 and beyond

The study is designed as a follow-up cohort study. The participants comprise surviving members of the Scottish Mental Survey of 1947 (SMS1947; N = 70,805) who reside in the Edinburgh area (Lothian) of Scotland. The SMS1947 applied a valid test of general intelligence to all children born in 1936 and attending Scottish schools in June 1947. A total of 1091 participants make up the Lothian Birth Cohort 1936. They undertook: a medical interview and examination; physical fitness testing; extensive cognitive testing (reasoning, memory, speed of information processing, and executive function); personality, quality of life and other psycho-social questionnaires; and a food frequency questionnaire. They have taken the same mental ability test (the Moray House Test No. 12) at age 11 and age 70. They provided blood samples for DNA extraction and testing and other biomarker analyses. Here we describe the background and aims of the study, the recruitment procedures and details of numbers tested, and the details of all examinations.The principal strength of this cohort is the rarely captured phenotype of lifetime cognitive change. There is additional rich information to examine the determinants of individual differences in this lifetime cognitive change. This protocol report is important in alerting other researchers to the data available in the cohort.There are increasing numbers of elders in the UK population, and the problems of ageing are deservedly attracting more research interest [1]. Cognitive decline is the single most feared aspect of growing old [2]. Identifying the cerebral basis for age-related cognitive decline is amongst the greatest challenges to improving the health of older people [3]. Age-related cognitive decline reduces quality of life, is an increasing burden to sufferers and their families, and places a massive financial load on society [4]. The spectrum of decline ranges from normal cognitive ageing, through Mild Cognitive Impairment, to the dementias [5]