The contribution of smoking and obesity to income-related inequalities in health in England

Reducing avoidable inequalities in health is a priority in many health care systems, including the NHS in Great Britain. Evidence suggests that lifestyle factors may play a role in explaining socioeconomic inequalities in health. In this paper we measure the contribution of smoking and obesity to income-related inequality in health. We use the corrected concentration index to measure inequality across time and areas of England, and decomposition methods to quantify directly the contribution of smoking and obesity to income-related inequality. Instrumental variables regression is used to test the endogeneity of smoking and obesity. We use data from nine rounds of the Health Survey for England (1998-2006). The results show that there are significant income-related health inequalities in England, that the extent of the inequality varies by area, and that in some areas it has increased over time. Nationally, smoking and obesity make a significant but modest contribution to income-related inequality in health (2.3% and 1.2%, respectively). Despite the reduction in smoking prevalence, the contribution of smoking has slightly increased over time, due to its increasing concentration among the poor and its negative effect on health. While the prevalence of obesity is increasing, it is more equally distributed across society. The prevalence of these problems varies between areas, and so does the contribution they make to income-related inequalities in health.