In many Western countries, despite declining overall mortality from cardiovascular diseases (CVDs) since the 1970s, the relative difference in disease rates between the richest and poorest groups has widened.1 Both stroke and coronary heart disease (CHD), the main contributors to CVD mortality, have a multifactorial aetiology. However, debate continues about the relative importance of a large number of established and putative risk factors.1 2Reducing health inequalities has become an increasingly important policy objective over the past 20 years3 4 and interest has focused on how observed social inequalities in CVD can be reduced.4 5

The study by Bartley et al 6presents an ecological analysis that aims to shed some light on this question. Using data on men aged 20–64 years from two unrelated cross sectional studies 10 years apart they have compared the prevalence and social distribution of a range of behavioural, physiological and other risk factors. To examine the degree of inequality in the distribution of risk factors they used the Erikson-Goldthorpe (E-G) social class schema7 and calculated the relative index of inequality (RII)8 across social categories at each time period for each risk factor. These are relatively new methods that offer some methodological advantages.6

However, such studies …