Are gastrointestinal, gynecological and urogenital chronic overlapping pain conditions (COPCs) predisposing or perpetuating factors for orofacial pain (OFP)? A systematic review.

Orofacial pain (OFP) is a multidimensional clinical problem that includes conditions such as temporomandibular disorders (TMD). It is often associated with chronic overlapping pain conditions (COPCs), including gastrointestinal, gynecological and urogenital disorders. Despite previous reviews, uncertainty remains regarding temporality, the effect size and evidence certainty. This systematic review and meta-analysis, registered in PROSPERO, synthesized observational studies assessing the association between COPCs and OFP. Twenty-two studies met the inclusion criteria, of which 12 were eligible for quantitative synthesis. The risk of bias (RoB) was assessed with the Quality in Prognosis Studies (QUIPS) tool, and the certainty of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Longitudinal studies demonstrated, with moderate certainty, that irritable bowel syndrome (IBS) increases the risk of both first-onset and chronic OFP, including TMD and burning mouth syndrome. Cross-sectional evidence revealed associations of moderate magnitude between gastroesophageal reflux disease (GERD) and TMD, and large effects between polycystic ovary syndrome (PCOS) and TMD, though with lower certainty due to methodological limitations. Other conditions, such as interstitial cystitis (IC), gastritis, inflammatory bowel disease (IBD), and endometriosis, were supported by limited and low-certainty evidence. Overall, findings underscore the importance of considering COPCs in the clinical evaluation of OFP and support multidisciplinary approaches to management. Further high-quality longitudinal research is needed to establish causal relationships and inform mechanism-based treatment strategies.