Recovery and recurrence of mental sickness absence among production and office workers in the industrial sector.

BACKGROUND Manual workers in the public sector have previously been found to be at risk of mental sickness absence (SA). As the impact of mental illness differs across economic sectors, this study investigated mental SA in the industrial sector, differentiating between office and production workers. METHODS Ten-year observational cohort study including 14 369 (8164 production and 6205 office) workers with a total of 101 118 person years. SA data were retrieved from an occupational health register. Mental SA episodes were medically certified as emotional disturbances [10th version of the International Classification of Diseases (ICD-10 R45)] or mental and behavioural disorders (ICD-10 F00-F99). The first mental SA episode since baseline was called index mental SA. Recurrences were defined as any mental SA episode occurring >28 days after recovery from index mental SA. RESULTS The incidence of mental SA was higher in production workers than in office workers, but office workers needed longer time to recover from mental SA. Mental SA recurred as frequently in production workers as in office workers. The median time to recurrence was 15.9 months and tangibly shorter in office workers (14.9 months) than in production workers (16.7 months). Production and office workers aged >55 years were at increased risk of recurrent mental SA within 12 months of recovery from index mental SA. CONCLUSIONS The incidence of mental SA was higher in production workers than in office workers, whereas recurrence rates did not differ between them. Occupational health providers should pay special attention to older workers as they are at increased risk of recurrent mental SA.