Background: Sickness absence (SA) is becoming a major economic problem in many countries. Our aim was to investigate whether type of employment, including temporary employment or part-time employment, is associated with SA while controlling for familial factors (genetic and shared environment). Differences between men and women and across employment sectors were explored.

Methods: This is a prospective twin study based on 21 105 twins born in Sweden 1959-85. The participants completed a survey in 2005 with follow-up of SA (≥15 days), using register data, until end of 2013. The data were analyzed with logistic regression, with results presented as odds ratios (OR) with 95% confidence intervals (CI).

Results: Temporary employment involved higher odds of SA (OR=1.21 95% CI=1.04-1.40) compared to full-time employment. Both part-time workers (OR=0.84 95% CI=0.74-0.95) and the self-employed (OR=0.77 95%CI=0.62-0.94) had lower odds of SA. Stratifying by sex showed lower odds for part-timers (OR=0.82 95% CI=0.73-0.94) and self-employed women (OR=0.65 95% CI=0.47-0.90), but higher odds for men in temporary employment (OR=1.33 95% CI=1.03-1.72). Temporary employees in county councils (OR=1.73 95% CI=1.01-2.99) and municipalities (OR=1.41 95% CI=1.02-1.96) had higher odds while part-timers employed in the private sector had lower odds (OR=0.77 95% CI=0.64-0.93). Familial factors did not confound the association between employment type and SA.

Conclusions: Employment type is associated with SA, with temporary employment involving a higher risk compared to permanent full-time employment while both part-time employment and self-employment involved a lower risk. The associations vary between women and men and across sectors.