Childhood mental ability and smoking cessation in adulthood: prospective observational study linking the Scottish Mental Survey 1932 and the Midspan studies

Education, childhood IQ, and occupational social class are associated with mortality and morbidity. One possible cause of these associations is via their impact on health behaviours such as smoking.1 Less educated people are more likely to continue smoking,2 but smoking is more strongly related to occupational social class than to education.3 Childhood IQ is related to education and occupational social class.4 Here we investigate whether mental ability at age 11 is associated with stopping smoking in adulthood. The social and smoking data were from two of the Midspan prospective cohort studies conducted in the 1970s—the Collaborative study and the Renfrew/Paisley study. Participants completed a questionnaire and attended a physical examination.5 Occupational social class was coded according to the registrar general’s classification.6 The home address of the participants at the time of screening was retrospectively postcoded to allow deprivation category as defined by Carstairs and Morris to be ascertained.7 This is an area based measure obtained from four census variables—male unemployment, overcrowding, car ownership, and the proportion of heads of households in social classes IV and V. …