Social inequalities have a pervasive influence in almost all aspects of health and health service use. In many instances, as in smoking and lung cancer, the inequalities are a confounding variable and strategies of preventive action can address the primary cause. In those conditions where aetiology is uncertain, investigation of social inequalities may point to causal hypotheses and lead to successful preventive action.

Until 2001, the measures of social status used were the Registrar General’s Social Class (RGSC) based on levels of occupational skill or the more detailed socioeonomic status (SES) classification that brought together occupations of similar social and economic status.¹ Alternatively, proxy measures for affluence and deprivation based on census enumeration districts were applied to examine the association between incidence and prevalence rates of a large number of diseases. In the majority of instances, the association is an inverse one; the higher the social position or degree of affluence, the lower is the risk of disease.

In population studies of cerebral palsy there has been no consistent association observed. In this issue of Archives, Sundrum and colleagues examine the relation between cerebral palsy and socioeconomic status.² The authors draw attention to this in the summary of these studies shown in table 1 of their paper. However, in this report of a population based study of cerebral palsy in West Sussex, they position themselves clearly on that side of the fence favouring a strong inverse association between RGSC and cerebral palsy prevalence. The …