Editorial introduction: Social and spatial inequalities in health and mortality: the analysis of longitudinal register data from selected European countries

Health inequalities—systematic differences in health outcomes between social groups and across spatial units—are ubiquitous, but not necessarily inevitable. They are the product of a complex interplay of social and economic processes operating at various scales. The unequal pattern of infection and death seen in the Covid-19 pandemic has served to highlight the stark social gradient in health that exists within many European countries. Although the complex social determinants of health have been studied for many decades, there is still a great deal of work to do to elucidate explanations for health inequalities across time and space. To rise to the challenge, we need high-quality, representative data capable of capturing multi-scalar longitudinal processes. This special issue brings together eight new studies which all use national population register data linked with various other sources of administrative data (e.g., residence, tax and health records) to investigate different vectors of inequalities in health and mortality, covering spatial, socioeconomic, ethnic and migrant status. This editorial outlines their contributions, argues for the invaluable role of population register data to understand health inequalities and suggests promising future research avenues.