The influence of observed and unobserved family background on mortality – evidence from Finnish register data on siblings and their parents

Hannes Kröger, European University Institute
Lasse Tarkiainen, University of Helsinki
Pekka Martikainen, University of Helsinki
Rasmus Hoffmann, European University Institute

In this study, we address the question how much socioeconomic position of siblings and their parents contributes to the explanation of differences in mortality risk between families. We provide three estimates of the overall family influence on mortality that are based on the family level variance in survival analytic regression model using siblings nested in families as the units of analysis. The study uses a sample of Finnish siblings born between 1936 and 1950 obtained from Finnish census data. Individuals are followed from age 35 up to age 72. To explain family influence on mortality, demographic background factors, the socioeconomic position of the parents and the siblings’ own socioeconomic position at age 35 are used as predictors of all-cause and cause-specific mortality. Results show that family influence is higher for alcohol, CVD, accidents, lung cancer related deaths than for all-cause mortality and mortality related to other forms of cancer than lung cancer. Jointly, demographic and socioeconomic factors, including region, number of siblings, native language, education and occupation of parents, income, occupation, tenancy status and education of the siblings explain between 10 and 25% of the total family influence on mortality. Socioeconomic variables of the siblings make the largest contribution in explaining family influence for all causes of mortality. However, a large portion of the influence of the family on mortality is not explained by individual and parental socioeconomic position highlighting the need to investigate family influence on mortality in comprehensive framework including demographic, social, behavioral and genetic information.