Predictors of new onsets of Irritable Bowel Syndrome, Chronic Fatigue Syndrome and Fibromyalgia: The Lifelines study, by Rei Monden, Judith G Rosmalen, Klaas Wardenaar, Francis Creed, Manuscript Number: THELANCET-D-19-04796 (July 26, 2019). at SSRN:
It is unclear whether the functional somatic syndromes share a common etiology or have distinct syndrome-specific mechanisms. This prospective population-based study assessed whether the same variables predict new onsets of self-reported Irritablebowel syndrome (IBS), Chronic Fatigue Syndrome (CFS) and Fibromyalgia (FM).
The study included adults participating in the Dutch Lifelines population-based study who reported the presence/absence of IBS, CFS or FM at baseline and follow-up (N=152,180). They were screened at baseline for physical and psychological disorders, ociodemographic, psycho-social and behavioral variables. At follow-up (mean 2.4 years) we identified new onsets of each syndrome by self-report. We performed separate analyses for the three syndromes, including only those participants who, at baseline, were free of the relevant syndrome or its key symptom. LASSO logistic regressions were applied to identify which of the 102 baseline variables predicted new onsets of each syndrome.
The numbers of new onsets were 1,595 (1.2%), 296 (0.2%) and 692 (0.5%) for IBS, CFS, and FM respectively. LASSO logistic regression selected 26, 7 and 19 predictors for IBS, CFS and FM respectively. Four predictors were shared by all three syndromes: somatic symptoms, disturbed sleep, recent chronic illness and negative health perception. Female sex, allergies, gastrointestinal disorders, high BMI and low alcohol consumption predicted both IBS and FM; recent stress predicted both IBS and CFS but 28 predictors were specific to a single syndrome. CFS was more distinct from IBS and FM, which predicted each other.
Syndrome-specific predictors were more common than shared ones. Such specific predictors might form a better starting point to unravel the heterogeneous etiologies of these syndromes than the current approach based on symptom patterns. The close relationship between IBS and FM is striking and the shared role of allergies, gastrointestinal and other medical disorders and medications needs further investigation.