Is there an interaction between self-rated health and medication with analgesics and hypnotics in the prediction of disability pension?

Aims: Several studies have shown that self-rated health (SRH ) is associated with drug use. The aim of this study was to investigate the possible interaction between SRH and use of analgesics and hypnotics and its ability to predict disability pension. Methods: In 1974-78, complete birth-year cohorts of middle-aged male residents in Malmö, Sweden, were invited to a health screening, and the cohort in this study comprised 5,798 men with complete data followed up for 11 years. Results: At inclusion, 27% rated their health as less than perfect, 11% used analgesics, 3% used hypnotics and, during follow-up, 12% received a disability pension. The adjusted hazard ratios of disability pension were 3.1 (CI: 2.6, 3.6) for those who had rated their health as less than perfect and 2.7 (2.3, 3.2) for subjects who used analgesics and/or hypnotics. For subjects with the combined risk of poor SRH and medication, the hazard ratio was 5.5 (4.6, 6.5). The granting of disability pension attributable to the interaction between poor SRH and medication was estimated at 47%, which was statistically significant. Conclusions: Disability pension among middle-aged men was associated with self-rated health as well as medication and clear evidence of synergism between the two factors was found, while there were no indications of medication acting as a causal link between poor SRH and disability pension. Several mechanisms may contribute to the findings, but the information gained may be used as means to identify those at risk for disability pension