To investigate the impact of employment characteristics on the occurrence of long-term sickness absence taking socioeconomic covariates into account. A longitudinal analysis was conducted for 62,745 employees aged 18 to 64 during 1990-1999. A nonlinear random-effects model was used. In particular, the missing data patterns and their relationship with sickness absence were studied. Strong relationship of socioeconomic background with occurrence of long-term sickness absence (≥ 3 days) was found. The missing data patterns significantly predicted sickness absence for female employees. In subsequent analysis, the discontinuous employment history with high occurrence of short-term sickness absence (<3 days) appeared to be strongly linked to long-term sickness absence in young women. An investigation of missing values and short-term sickness absence as predictors for long-term sickness absence uncovered that young women with irregular employment history constituted high-risk employees.