Asthma and multiple sclerosis: an inverse association in a case‐control general practice population

• Published in: QJM : An International Journal of Medicine Vol. 95; no. 11; pp. 753 - 756
• Main Authors: Tremlett, H.L., Evans, J., Wiles, C.M., Luscombe, D.K.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-11-2002; Oxford Publishing Limited (England)
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Arthritis, Rheumatoid - epidemiology; Asthma - complications; Asthma - epidemiology; Asthma - immunology; Biological and medical sciences; Case-Control Studies; Chronic obstructive pulmonary disease, asthma; Diabetes Mellitus, Type 1 - epidemiology; Eczema - epidemiology; Family Practice; Female; Humans; Inflammatory Bowel Diseases - epidemiology; Male; Medical sciences; Middle Aged; Multiple Sclerosis - complications; Multiple Sclerosis - epidemiology; Multiple Sclerosis - immunology; Pneumology; Retrospective Studies; Risk Factors; Wales - epidemiology; Wales; Human; Nervous system diseases; Correlation; Multiple sclerosis; Respiratory disease; Central nervous system disease; Obstructive pulmonary disease; Epidemiology; Public health; Inflammatory disease; Asthma
• ISSN: 1460-2725; 1460-2393; 1460-2393
• DOI: 10.1093/qjmed/95.11.753

Background: Th1/Th2 imbalance is hypothesized to up‐regulate some diseases and down‐regulate others. Compared to controls, multiple sclerosis (MS) (Th1‐mediated) has been linked to a reduced risk of allergy and asthma (Th2‐mediated), based on patient questionnaire studies and a review of asthma medication. Aim: To investigate whether MS is associated with a reduced risk of Th2‐associated diseases and an increased risk of Th1‐associated diseases. Design: Retrospective matched case‐control study. Methods: Three hundred and twenty MS patients and controls matched for age, gender, location and smoking were selected from the Welsh General Practice Morbidity Database from 1995–99. Case and control records were assessed for Th1‐mediated and Th2‐mediated diseases. Results: Overall, 346 MS patients were identified, giving a prevalence of 127 per 100 000. There was an inverse relationship between multiple sclerosis (MS) and asthma (OR 0.33; 95%CI 0.15–0.77). No statistically significant relationships emerged between other Th2‐associated (eczema, dermatitis) or any Th1‐associated (rheumatoid arthritis, thyroid disorders, inflammatory bowel disease [IBD], type 1 diabetes) diseases and MS, although no patient in either group had treated type 1 diabetes. A trend existed for IBD, with 5/320 of cases affected and no controls; OR ∞; 95%CI 1.30–∞; p=0.063. Discussion: This inverse association between MS and asthma is compatible with a Th1/Th2 imbalance. Although the Th1/Th2 theory is probably an over‐simplification in MS, a shift from Th1 cytokine dominance towards Th2 may provide drug‐targeting routes for MS.