The aim of this doctoral thesis is to study early life exposures in relation to adult health in Sweden during 250 years. The early life exposures investigated are the foetal origins (nutrition) and the inflammation hypotheses. Longitudinal individual and household data are combined with local area data on food costs (rye prices) and disease load (infant mortality rate, IMR) using a Cox regression framework to analyse the 55-80 year mortality in four parishes in Scania, southern Sweden, in the 18th and 19th centuries. Register based cohort data on individuals in late 20th century Sweden born in eleven countries in 1921-1939 are analysed in Cox regressions of adult mortality, including IMR and GDP per capita in the year and country of birth. A survey (2008) in Scania is used to analyse self-reported early life socioeconomic data and IMR in the birth year in relation to adult self-rated health (SRH). Results from the historical studies suggest that cohorts exposed to high IMR have high mortality in ages 55-80 specifically from airborne infectious diseases and that a high disease load of airborne infectious diseases in infancy has a strong impact on later life mortality, while hypotheses concerning food costs (nutrition) and disease load during pregnancy are not supported. Essentially no adult socioeconomic mortality differences are observed. In the two modern time studies individual adult and early life socioeconomic conditions are associated with adult mortality and SRH, respectively, while IMR and GDP per capita are mostly not.