Monday, 13 May 2013

Risk of MS after surgery

Tonsillectomy and appendectomy before the age of 21 is associated with a higher risk of MS. #MSBlog #MSResearch

"Tonsillectomy and appendectomy before the age of 21 is associated with a higher risk of MS. Why? Could it be a simple association with infection? People who have tonsillectomies typically have a history of recurrent sore throats. Similarly, appendectomy or removal of the appendix is for infection of the appendix or appendicitis. May be the risk factor is infection. We know that about a third of relapses are triggered by symptomatic infections occurring in the 4-6 week period prior to the onset of the relapse; presumably this applies to the initial relapse at symptomatic onset of MS. How infections trigger relapses is unknown, but are speculated to non-specifically boost or stimulate the immune system. This is why it makes sense to try and avoid infections as much as possible. This is easier said than done."

Epub: Lunny et al. Surgery and risk for multiple sclerosis: a systematic review and meta-analysis of case--control studies. BMC Neurol. 2013 May 6;13(1):41.

BACKGROUND: Although the precise aetiology of MS 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, this study aimed to examine surgery as a risk factor for the diagnosis of MS.

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

RESULTS: They identified 33 case--control studies, involving 27,373 MSers 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 MS. There was no statistically significant association between risk for MS 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 MS diagnosis was not statistically significant (OR = 1.19, 95% CI 0.83-1.70; I2 = 71%).


CONCLUSIONS: They found a small but statistically significant and clinically important increased risk for developing MS, 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 MS. Well-designed prospective etiological studies, pertaining to the risk for developing MS, ought to be conducted and should include the examination of various surgeries as risk factors.


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