Small intestinal bacterial overgrowth in Parkinson's disease

Ai Huey Tan, Sanjiv Mahadeva, Abdul Malik Thalha, Peter Raymond Gibson, Chiun Khang Kiew, Chia Ming Yeat, Sheang Wen Ng, Sheau Phing Ang, Siew Kian Chow, Chong Tin Tan, Hoi Sen Yong, Connie Marras, Susan H Fox, Shen-Yang Lim

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Recent studies reported a high prevalence of small intestinal bacterial overgrowth (SIBO) in Parkinson s disease (PD), and a possible association with gastrointestinal symptoms and worse motor function. We aimed to study the prevalence and the potential impact of SIBO on gastrointestinal symptoms, motor function, and quality of life in a large cohort of PD patients. Methods: 103 Consecutive PD patients were assessed using the lactulose-hydrogen breath test; questionnaires of gastrointestinal symptoms and quality of life (PDQ-39); the Unified PD Rating Scale (UPDRS) including on -medication Part III (motor severity) score; and objective and quantitative measures of bradykinesia (Purdue Pegboard and timed test of gait). Patients and evaluating investigators were blind to SIBO status. Results: 25.3 of PD patients were SIBO-positive. SIBO-positive patients had a shorter mean duration of PD (5.2?4.1 vs. 8.1?5.5 years, P=0.007). After adjusting for disease duration, SIBO was significantly associated with lower constipation and tenesmus severity scores, but worse scores across a range of on -medication motor assessments (accounting for 4.2-9.0 of the variance in motor scores). There was no association between SIBO and motor fluctuations or PDQ-39 Summary Index scores. Conclusions: This is the largest study to date on SIBO in PD. SIBO was detected in one quarter of patients, including patients recently diagnosed with the disease. SIBO was not associated with worse gastrointestinal symptoms, but independently predicted worse motor function. Properly designed treatment trials are needed to confirm a causal link between SIBO and worse motor function in PD.
Original languageEnglish
Pages (from-to)535 - 540
Number of pages6
JournalParkinsonism & Related Disorders
Issue number5
Publication statusPublished - 2014

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