Prospective register-based study of the impact of immigration on educational inequalities in mortality in Norway

BACKGROUND Differences in mortality with regard to socioeconomic status have widened in recent decades in many European countries, including Norway. A rapid upsurge of immigration to Norway has occurred since the 1990s. The article investigates the impact of immigration on educational mortality differences among adults in Norway. METHODS Two linked register-based data sets are analyzed; the first consists of all registered inhabitants aged 20-69 in Norway January 1, 1993 (2.6 millions), and the second of all registered inhabitants aged 20-69 as of January 1, 2008 (2.8 millions). Deaths 1993-1996 and 2008-2011, respectively, immigrant status, and other background information are available in the data. Mortality is examined by Cox regression analyses and by estimations of age-adjusted deaths per 100,000 personyears. RESULTS Both relative and absolute educational inequality in mortality increased from the 1993-1996 period to 2008-2011, but overall mortality levels went down during these years. Immigrants in general, and almost all the analyzed immigrant subcategories, had lower mortality than the native majority. This was due to comparatively low mortality among lower educated immigrants, while mortality among higher educated immigrants was similar to the mortality level of highly educated natives. CONCLUSIONS The widening of educational inequality in mortality during the 1990s and 2000s in Norway was not due to immigration. Immigration rather contributed to slightly lower overall mortality in the population and a less steep educational gradient in mortality.