A life course study of genetic and environmental influences on sustainable working life.

Genetics plays a role in short- and long-term sustainable working life (i.e., not having interruptions due to sickness absences (SA), disability pensions (DP), or unemployment), but the life course effects are not known. Thus, we aimed to investigate the age-specific genetic and environmental influences on sustainable working life from young adulthood until old-age pension. We used classical twin modeling based on the genetic relatedness of mono- and dizygotic twins in a longitudinal design. The final sample (n =  49 372) of Swedish same-sex twins with known zygosity born between 1929 and 1990 (52.8% women) with detailed national register data of employment, SA, DP, unemployment, old-age pension, emigration, and death. Genetic influences for sustainable working life were 54% at ages 18-27 years, 59% at 28-37 years, 37% at 38-47 years, 69% at 48-57 years, and 34% at 58-65 years. We observed genetic influences transferred from 18-27 years to 28-37 years and to 38-47 years explaining 28% and 17% of the variance, respectively, from 28-37 years to 38-47 years 60%, and from 48-57 years to 58-65 years 47%. Unique environmental influences were 57-72% in five age groups. Age group-specific common environment explained 63% of the variance for 18-27 years, 27% for 28-37 years, 12% for 48-57 years, and 25% for 58-65 years (none for 38-47 years). From age 48-57 years, the common environment explained 24% of the variance among those aged 58-67. To conclude, stability and change in genetic effects are important for a sustainable working life across the life course. The unique environmental effects were important for the middle age groups between 28 and 57 years. Thus, society and workplaces should support health and well-being to promote a sustainable working life.