Sex and Gender Differences in Overlap Syndrome of Functional Gastrointestinal Disorder and Effect of Genetic Polymorphisms in South Korea: A Long-term Follow-up Study.

Background/aims: Overlap functional gastrointestinal disorder (FGID) is associated with more severe gastrointestinal symptoms and lower quality of life. The aim of this study is to evaluate clinical features of non-erosive reflux disease (NERD), functional dyspepsia, irritable bowel syndrome, their overlap in terms of sex and gender, and to assess the risk factors, including genetic polymorphisms.

Methods: A total of 494 FGIDs and 239 controls were prospectively enrolled between 2004 and 2020. FGIDs were diagnosed based on the Rome III criteria and symptoms were evaluated using a questionnaire. Follow-up questionnaires were conducted to determine the change of symptoms during the 75.8-month mean observation period. Risk factors including genetic polymorphisms in neurotransmitter receptor (, and ) and cytokine ( and ) genes.

Results: NERD was more prevalent in men, and functional dyspepsia in women. Overlap FGIDs (n = 239) were more prevalent than nonoverlap FGIDs (n = 255) in women ( = 0.019). Anxiety and depression scores were higher in the overlaps ( = 0.012 and < 0.001, respectively). Symptoms were more frequent and severe in the overlap FGIDs than in the non-overlaps ( < 0.001). During followup, symptoms progressed more frequently in the overlap FGIDs, especially in patients with the L/S genotype of and anxiety/depression.

Conclusions: Overlap FGID patients need attention given their association with anxiety/depression and more severe symptoms, especially in women. Genetic polymorphisms also may be associated with certain symptoms of overlap FGIDs.