Bodily distress syndrome (BDS) has been shown to encompass a range of functional somatic syndromes (FSS) such as irritable bowel syndrome (IBS), fibromyalgia (FM), and chronic fatigue syndrome (CFS) in clinical samples. This study aimed to explore symptom clusters and test classification of individuals with illness similar to the BDS criteria in a general population sample.
A stratified subsample of 1590 individuals from the DanFunD part two cohort was included. Symptoms were assessed with the Research Interview for Functional somatic Disorders, performed by trained physicians. In 44 symptoms pooled from criteria of IBS, FM, CFS, and BDS, symptom clusters were explored with explorative factor analysis. Confirmation of symptom clusters of BDS in the previously described 25- and 30-item BDS checklists was performed with confirmatory factor analysis. Classification of individuals into illness groups was investigated with latent class analysis.
Four symptom clusters (cardiopulmonary, gastrointestinal, musculoskeletal, general symptoms/fatigue) corresponding to the BDS subtypes and their corresponding FSS were identified and confirmed. A three-class model including 25 BDS items had the best fit for dividing participants into classes of illness: One class with low probability, one class with medium probability, and one class with high probability of having ≥4 symptoms in all symptom clusters.
The BDS concept was confirmed in the general population and constitutes a promising approach for improved FSS classification. It is highly clinical relevant being the only diagnostic construct defining the complex multi-organ type.