Socioeconomic conditions in childhood and ischaemic heart disease during middle age OBJECTIVE--To examine the association between socioeconomic conditions in childhood and ischaemic heart disease in middle aged men, including the role of physiological and behavioural risk factors. DESIGN--Prevalence study with extensive examination and testing and with recall of childhood conditions. SETTING--Population based study in Kuopio, Finland. SUBJECTS--Representative sample of 2679 men aged 42, 48, 54, and 60. MAIN OUTCOME MEASURES--Ischaemic findings on progressive maximal exercise test. RESULTS--Low socioeconomic style in childhood was associated with significantly higher prevalence of findings indicating ischaemias. Compared with those in the highest tertile of childhood socioeconomic conditions, the age adjusted odds ratio for subjects in the lowest tertile was 1.44 and for those in the middle tertile 1.35. Adjustment for years of cigarette smoking times the average number of cigarettes smoked, ratio of high density lipoprotein to low density lipoprotein cholesterol, fibrinogen and serum selenium concentrations, and adult height did not appreciably weaken the association. Adjustment for adult socioeconomic state resulted in a 16% decline in the association. The association was reduced to non-significance by adjustment for measures of prevalent cardiovascular illness. CONCLUSIONS--Socioeconomic state in childhood was significantly associated with ischaemic heart disease in middle aged men. Levels of risk factors measured at middle age did not account for this association, nor did adult height. Because childhood socioeconomic conditions precede the development of ischaemic heart disease the substantial impact of prevalent illness on the observed association suggests that ischaemic heart disease develops earlier in those with lower socioeconomic state during childhood. 