Objectives Socioeconomic position (SEP) in childhood and in adulthood, and work environment factors are predictors of sickness absence (SA). Our objective was to examine the relationships between these factors in a life-course perspective, which has hardly been done previously.

Method Our study sample was all employed individuals who partook in the HUNT study and who were born between 1967 and 1976 (N = 4530). Outcome was the risk of at least one SA episode in 2009. Educational attainment (5 categories) served as indicator of adult SEP, whereas highest parental education level and father’s average income during early childhood (0–6 years) were indicators of childhood SEP. Work factors were job control, physically demanding work and shift work. Risk ratios (RRs) were estimated using Poisson regression.

Results 29% of the women and 17% of the men had SA during follow-up. There was a strong gradient according to adult SEP for both genders. The age-adjusted RR for having an SA episode, comparing highest and lowest educational levels, was 2.83 for women and 3.85 for men. The RR was marginally weakened in women (-4%) and strengthened in men (+18%), after adjusting for childhood SEP (Model 2). Including all work factors in the model reduced the RRs by 20% compared to Model 2 (RR 2.20 and 3.62, respectively), the largest impact for physically demanding work (15% reduction in RR).

Conclusions There were strong social gradients in SA, partly mediated through work environment factors in a life-course perspective. We found gender differences that are difficult to explain.