Larsson K et al. (2006) Early menopause, low body mass index, and smoking are independent risk factors for developing giant cell arteritis. Ann Rheum Dis 65: 529–532

Results of a case–control study in Sweden suggest that pathogenesis of the chronic, inflammatory disorder giant cell arteritis (which has a high incidence in Scandinavian ethnic groups), is affected by levels of female sex hormones. Larsson and colleagues found that low BMI, menopause before the age of 43, smoking, and longer duration of breast feeding were all independent risk factors associated with giant cell arteritis.

The authors identified 65 cases of biopsy-proven giant cell arteritis in women aged 50–69 years at diagnosis; the 49 women who responded to a questionnaire on hormonal and reproductive factors were included in the study. Controls were 10,405 women who had responded to the same questionnaire as part of a Swedish national breast-cancer prevention program.

Giant cell arteritis mainly affects postmenopausal women, who experience an age-related decline in production of adrenal steroids and gonadal hormones. Larsson and colleagues suggest that extended periods of low production of female sex hormones suppress the hypothalamic–pituitary–gonadal axis and blunt the responsiveness of the hypothalamic–pituitary–adrenal axis, thereby exacerbating inflammatory processes.

Postmenopausal women with low BMI have high levels of sex-hormone-binding globulin and low levels of estrone (the principal estrogen in postmenopausal women, which is produced mainly in adipose tissue). Interestingly, smoking is known to reduce BMI and decrease estrone synthesis, and is also associated with early onset of menopause, but was an independent risk factor for giant cell arteritis in this study.