Swedish registers - a gold mine for medical research

Håkan Sjöberg, Statistics Sweden
Andreas Blomquist, Statistics Sweden

The detailed comprehensive registers with information on all the registered population held by authorities in Sweden and other Nordic countries are of great value for Swedish research institutions and often yield competitive advantages towards researchers outside of the Nordic countries, unable to access similar data. Comprehensive national data registers and a system with unique personal identification numbers makes it possible to track individuals over long periods of time in longitudinal studies. Statistics Sweden hold total population registers from1968 onwards, both stocks and flows with information on various demographic aspects. The population registers can be linked to other comprehensive records on generational relationships, labour market, welfare, income, education, geography etc. By collaboration with other authorities such as The National Board of Health and Welfare, Statistics Sweden can administer the compilation of databases on health, risk factors and background variables to be used in medical research. A study population, or cohort, may be defined as a cross section of the population, a randomized sample or be derived using specific characteristics such as age, sex, residential area, etc. using population registers. Study populations derived from diagnosed disease or special risk factors yields collaboration with other authorities. In case control studies two existing groups, differing in outcome or exposure, are identified and compared on the basis of some supposed causal attribute. Due to the population registers, it is possible to match cases and control individuals by age, sex and residential area at the time of outcome. Data on the spatial patterns of disease and exposure can provide useful tools for analysis. The Geographical information database at Statistics Sweden enable linkage of all residents and most workplaces in Sweden to coordinates and enable the use of Geographic information systems (GIS). In short, registers held at Statistics Sweden and other authorities present vast opportunities for research.