Allergy and multiple sclerosis: a population-based case-control study.
BACKGROUND
Epidemiological studies on the association between allergic disorders, T-helper type 2 (Th2) mediated, and multiple sclerosis (MS), a T-helper type 1 (Th1)/Th17-mediated disease, provided conflicting results.


OBJECTIVE
The aim of this study was to further examine the association between allergic disorders and MS.


METHODS
The association between MS and previous medical history of any type of allergy has been investigated in a population-based case-control study conducted in Northern Italy, based on telephone interviews to 423 cases and 643 population controls (refusal rates 3.7% and 9.4%, respectively). Controls were a random sample of the general population.


RESULTS
A history of atopic allergies seems to confer protection against MS (odds ratio [OR], 0.58; 95% confidence interval [CI], 0.38-0.89; P = 0.012). In particular, the prevalence of allergic asthma was 4.9% in people with MS and 12% in control subjects (OR = 0.38; 95% CI 0.22-0.66, P < 0.01). No association was found between MS and nonatopic allergies.


CONCLUSIONS
Our findings are confirmatory of the putative protective effect of Th2-mediated disorders on Th1 immune responses associated with MS. A unifying theory on the mechanisms by which previous history of atopic allergies may modify the risk of MS is still lacking.
Pedotti
R
R
Neurological Institute Foundation IRCCS Carlo Besta, Milan, Italy. rpedottie@istituto-besta.it
Farinotti
M
M
Falcone
C
C
Borgonovo
L
L
Confalonieri
P
P
Campanella
A
A
Mantegazza
R
R
Pastorello
E
E
Filippini
G
G
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology* / Q000276:immunology; D007558:Italy / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D016017:Odds Ratio; D011159:Population Surveillance; D015995:Prevalence; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D055815:Young Adult