Early menopause, low body mass index, and smoking are independent risk factors for developing giant cell arteritis

Objective: To assess female sex hormone related variables in a group of women with biopsy positive giant cell arteritis and a control group. Methods: 49 women with biopsy positive giant cell arteritis, aged 50 to 69 years at the time of diagnosis, answered a questionnaire on hormonal and reproductive factors. The same questions were answered by a large population of women from the same geographical area in connection with routine mammograms. The results were tested statistically, using logistic regression analysis of each variable adjusted for age, and a multivariate logistic regression analysis including age and the variables which differed significantly between giant cell arteritis and controls. Results: From the multivariate logistic regression analysis, three independent variables were associated with an increased risk of having giant cell arteritis: smoking and being an ex-smoker (odds ratio (OR) = 6.324 (95% confidence interval (CI), 3.503 to 11.418), p<0.0001); body mass index (a reduction of 1.0 kg/m(2) increased the risk by 10% (OR = 0.898 (0.846 to 0.952), p = 0.0003); and menopause before the age of 43 (OR = 3.521 (1.717 to 7.220), p = 0.0006). Conclusions: There was a significant association between hormonal and reproduction related factors and the risk of developing giant cell arteritis in women given the diagnosis before the age of 70. The results suggest a possible role of oestrogen deficiency in the pathogenesis of giant cell arteritis. To confirm the results, an extended study will be needed, including women older than 70.