The Scottish mental survey 1932 linked to the Midspan studies: a prospective investigation of childhood intelligence and future health.

The Scottish mental survey of 1932 (SMS1932) recorded mental ability test scores for nearly all children born in 1921 and at school in Scotland on 1 June 1932. The Collaborative and Renfrew/Paisley studies, two of the Midspan studies, obtained health and social data by questionnaire and a physical examination in the 1970s. Some Midspan participants were born in 1921 and may also have taken part in the SMS1932, so there was a possibility that their mental ability data from childhood would be available. The 1921 born Midspan participants were matched with the computerized SMS1932 database, and in total, 1032 of 1251 people (82.5%) were matched successfully. Of those matched, 938 (90.9%) had a mental ability test score recorded. The mean score of the matched sample was 37.2 (standard deviation (SD) 13.9) out of a possible score of 76. The mean (SD) for the boys and girls was 38.3 (14.2) and 35.7 (13.9), respectively. This compared with 38.6 (15.7) and 37.2 (14.3) for boys and girls in all of Scotland. Graded relationships were found between mental ability in childhood, and social class and deprivation category of residence in adulthood. Being in a higher social class or in a more affluent deprivation category was associated with higher childhood mental ability scores, and the scores reduced with increasing deprivation. Future plans for the matched data include examining associations between childhood mental ability and other childhood and adult risk factors for disease in adulthood, and modelling childhood mental ability, alongside other factors available in the Midspan database, as a risk factor for specific illnesses, admission to hospital and mortality.