Socioeconomic disparities in morbidity and mortality have become a topic of major interest in public health. Voluminous evidence demonstrates the importance of socioeconomic status (SES) for an impressive range of health conditions: obesity, depression, cardiovascular disease, chronic headache, etc. In the April issue of the journal, Kaila-Kangas and colleagues¹ reported on SES differences in first hospitalisation for back disorders.

There is little consensus about the mechanism of the SES–health gradient. Proposed causal pathways—not necessarily mutually exclusive—include material deprivation, adverse “lifestyle” conditions (smoking, poor nutrition, etc), inadequate access to health information, and relative deprivation leading to social mistrust.²

Debate has also arisen over the “best” indicator of SES,^3,4 and especially whether it should be assessed in terms of an individual’s social status or prestige (often in terms of personal access to goods, services, and knowledge) or at the level of a group’s social and economic control of resources.^5,6

While key variables such as education, grade of …