Association between Appendectomy and Demyelinating Disorders in Subjects 40 Years and Older

Area of Science:

• Neurology
• Immunology
• Gastroenterology

Background:

• The relationship between appendectomy and neurological disorders like multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) is not well understood.
• This study investigates potential associations between prior appendectomy and the incidence of MS and NMOSD.

Purpose of the Study:

• To determine if there is an association between appendectomy and multiple sclerosis (MS).
• To investigate the association between appendectomy and neuromyelitis optica spectrum disorder (NMOSD).

Main Methods:

• A case-control study was conducted in Malaysia involving patients diagnosed with MS or NMOSD (aged over 40) and healthy controls.
• Data on appendectomy history were collected via interviews, with diagnoses confirmed using established criteria (Revised McDonald 2010 for MS, Wingerchuk 2015 for NMOSD).
• The age criterion (over 40) was used to differentiate risk as appendicitis incidence decreases significantly after this age.

Main Results:

• The study included 49 MS patients, 71 NMOSD patients, and 880 controls.
• Appendectomy rates were significantly higher in the MS group (18.37%) compared to both the NMOSD group (5.6%) and controls (6.7%) (P = 0.007 for MS vs. controls).
• Multiple sclerosis was identified as an independent risk factor for appendectomy (OR 2.938, P = 0.009), while NMOSD showed no significant association.

Conclusions:

• Multiple sclerosis is positively associated with a history of appendectomy.
• Unlike ulcerative colitis, which shows a negative association with appendectomy, MS demonstrates a positive link.
• A shared microflora composition between individuals with MS and those who have undergone appendectomy is hypothesized.