Surgery and Risk for Multiple Sclerosis

A Systematic Review and Meta-analysis of Case-Control Studies

Carole Lunny; Jennifer A Knopp-Sihota; Shawn N Fraser

Disclosures

BMC Neurol. 2013;13(41) 

In This Article

Abstract

Background: Although the precise etiology of multiple sclerosis is largely unknown, there is some speculation that a prior history of surgery may be associated with the subsequent risk for developing the disease. Therefore, we aimed to examine surgery as a risk factor for the diagnosis of multiple sclerosis.

Methods: We searched for observational studies that evaluated the risk for developing multiple sclerosis after surgery that occurred in childhood (≤ 20 years of age) or "premorbid" (> 20 years of age). We specifically included surgeries classified as: tonsillectomy, appendectomy, adenoidectomy, or "surgery". We performed a systematic review and meta-analyses and calculated odds ratios (OR) and their 95% confidence intervals (CIs) using a random effects model.

Results: We identified 33 case–control studies, involving 27,373 multiple sclerosis cases and 211,756 controls. There was a statistically significant association between tonsillectomy (OR = 1.32, 95% CI 1.08–1.61; 12 studies, I2 = 44%) and appendectomy (OR = 1.16, 95% CI 1.01–1.34; 7 studies, I2 = 0%) in individual's ≤ 20 years of age and the subsequent risk for developing multiple sclerosis. There was no statistically significant association between risk for multiple sclerosis and tonsillectomy occurring after age 20 (OR = 1.20, 95% CI 0.94–1.53; 9 studies, I2 = 32%), in those with appendectomy at > 20 years (OR = 1.26, 95% CI 0.92–1.72; 5 studies, I2 = 46%), and in those with adenoidectomy at ≤ 20 years of age (OR = 1.06, 95% CI 0.68–1.68; 3 studies, I2 = 35%). The combined OR of 15 studies (N = 2,380) looking at "surgery" before multiple sclerosis diagnosis was not statistically significant (OR = 1.19, 95% CI 0.83–1.70; I2 = 71%).

Conclusions: We found a small but statistically significant and clinically important increased risk for developing multiple sclerosis, in those with tonsillectomy and appendectomy at ≤ 20 years of age. There was no convincing evidence to support the association of other surgeries and the risk for multiple sclerosis. Well-designed prospective etiological studies, pertaining to the risk for developing multiple sclerosis, ought to be conducted and should include the examination of various surgeries as risk factors.

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