Giant cell arteritis and polymyalgia rheumatica: are pregnancies a protective factor? A prospective, multicentre case-control study. GRACG (Groupe de Recherche sur l'Artérite à Cellules Géantes).
OBJECTIVE
To assess the potential role of allo-immunization, either by former pregnancies, or by a history of blood transfusion, in the pathogenesis of giant cell arteritis and polymyalgia rheumatica.


METHODS
Two hundred and eighty-five incident female cases and 186 age-matched, population-based female controls were prospectively included in a multicentre case-control study.


RESULTS
The number of pregnancies was significantly lower in cases than in controls (nulliparous: 21.55% vs 12.90%; > or =4 pregnancies: 16.25% vs 27.42%; Wilcoxon rank sum test: P = 0.0019) in biopsy-proven or negative temporal arteritis and, to a lesser extent, in polymyalgia rheumatica. No difference was found for history of blood transfusion. Pregnancies remained negatively associated with the disease in a multivariate analysis including cardiovascular risk factors such as smoking or a pre-existing peripheral vascular disease.


CONCLUSIONS
Former pregnancies are not a risk factor for giant cell arteritis. Pregnancies may be protective thanks to an effect of the associated hyperoestrogenic state against alterations of the artery wall, as suggested in animal models.
Duhaut
P
P
Department of Internal Medicine, Edouard Herriot Hospital, Lyon, France.
Pinède
L
L
Demolombe-Ragué
S
S
Dumontet
C
C
Ninet
J
J
Seydoux
D
D
Loire
R
R
Pasquier
J
J
D000368:Aged; D002318:Cardiovascular Diseases / Q000150:complications; D016022:Case-Control Studies; D005260:Female; D013700:Giant Cell Arteritis / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D011111:Polymyalgia Rheumatica / Q000209:etiology* / Q000503:physiopathology; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects