Socio-economic status and risk for suicide by immigration background in Norway: A register-based national study.

The relative importance of socio-economic factors on risk for suicide in the immigrant population may differ from that for the native population; however, few studies have addressed this issue on a national basis. With a nested case-control design and data from Norwegian population registers we identified 11,409 suicide cases in the years 1992-2012 and 191,785 sex-birthdate-matched controls. The influence of socio-economic factors on the risk for completed suicide was assessed through conditional logistic regression. Among 11,409 suicides, 1139 (10%) were individuals with an immigration background of either themselves or their parent(s). Suicide cases, as well as the controls, with an immigration background differed in several aspects of their socio-economic status from those without such a background. Being single or separated, divorced or widowed, was, however, associated with an increased risk of suicide regardless to the subjects' immigration background. Low level of education and low annual income significantly increased the risk for suicide in almost all the study subgroups. Living in the capital area was associated with a reduced risk of suicide in first-generation immigrants but an increased risk in native Norwegians. In conclusion, persons with an immigration background, as well as native Norwegians, shared most common risk factors for suicide, but the strength of associations between socio-economic factors and risk for suicide can differ by immigration background.