Chronic respiratory diseases.

If this is true of diet and smoking it is even more true of the social environment: housing, the nature or work, education, social relationships.The research agenda for public health now should not only ask how best to achieve change in unhealthy behaviours but how to identify the social and economic causes of ill health, whether they act by affecting behaviours or by other means related to the environment; whether they act in adulthood or whether they act early in life.16s18Rose's insight on blood pressure and cholesterol applies also to social differences in ill health.People at the lower end of the social distribution, the poor, the homeless and the unem- ployed, have worse health than those better off.But although these individuals are at high risk and require attention, they are a minority within the population, and hence account for a minority of the burden of ill health attributable to social causes.The principal lesson from the study of social variations in ill health is that there is a gradient than runs right across society.'5A strategy for public health must deal with this important fact.