People in lower socio-economic groups are, in general, less healthy than people in higher groups. The size of the inequalities varies by the health indicator used. E.g. for indicators that relate to a biomedical concept of health, such as suffering from a chronic condition, inequalities seem to be smaller than for indicators representing a broader view on health, such as self-perceived health. Which indicators should guide health policy?
Galenkamp Henrike, Stronks Karien, Snijder Marieke B., Derks Eske M. Measurement invariance testing of the PHQ-9 in a multi-ethnic population in Europe: the HELIUS study BMC psychiatry 2017;17 (1):349 [PubMed]