Use of welfare benefits in multiple chemical sensitivity when compared to a general population - A registry and population-based cohort study

Background Multiple chemical sensitivity (MCS), characterized by adverse responses to extremely low levels of airborne chemicals, is often considered a functional somatic disorder (FSD). No standardized treatment exists and MCS individuals often cope by avoidance behaviour including adjustments in occupational life. Using Danish registry data, the aim was to investigate the use of welfare benefits in a 14-year period among Danish individuals with MCS. Methods Based on the Danish Study of Functional Disorders (DanFunD, 2011–2015), 177 MCS cases were identified via standardized validated questionnaires. The remaining study population without a FSD was regarded the reference as population (n  = 7578). Data on welfare benefits was assessed from the Danish Register for Evaluation of Marginalization. Comparisons were made between the two groups, 10 years retrospectively, and 4 years prospectively from participation in DanFunD. A secondary comparison group was individuals with type 2 diabetes. Results Retrospectively, a higher proportion of individuals with MCS received sickness benefit (29 % vs 48 %, p  < 0.05), disability pension (2 % vs 14 %, p < 0.05), and unemployment benefits (21 % vs 29 %, p < 0.05). 4 years prospectively, individuals with MCS had a higher relative risk (RR) of disability pension (RR: 2.73, 95 % CI 1.45, 5.16). Similar differences were seen when comparing with type 2 diabetes individuals. Conclusions During a 14-year period, compared to the general population, use of welfare benefits was higher in individuals with MCS primarily due to increased sickness leave and work disability. MCS has substantial influence on the individuals' occupational situation and is potentially a high burden on society.