Background Much of the information on the relationship between socioeconomic status (SES) and ischaemic heart disease (IHD) comes from ecological, cross-sectional and longitudinal mortality studies.

Such studies may present methodological problems which affect cohort studies and case-control studies to a lesser degree.

Methods A systematic review was conducted into the relationship between SES and IHD, as reported by cohort and case-control studies in which SES had been measured by education or occupation.

A bibliographic search, covering the period 1960-1993, was carried out using Index Medicus, MEDLINE, Sociological Abstracts, Social Scisearch and the references cited in papers identified in such databases.

Finally, 34 studies were selected, with data being extracted separately by two reviewers working independently.

Where differences of opinion arose, these were resolved by discussion between the two.

Multiple linear regression analysis was used to identify determinants of inter-study heterogeneity.

Results Risk of IHD was inversely related to educational level in the period 1982-1993.

There was a lower risk of IHD among manual workers versus non-manual workers until approximately 1970 ; thereafter the relationship became inverted.

The odds ratio for IHD in manual workers rose progressively over the period 1960-1993, something that could not be explained by study design, study size, study country or control for confounding factors. (...)