Early menopause, low body mass index (BMI), and smoking are all independent risk factors for developing giant cell arteritis (GCA), according to new research published in the online version of the Annals of Rheumatic Disease.¹ Also known as temporal arteritis and cranial arteritis, GCA causes swelling of the temporal arteries as well as arteries in the neck and arms. Women are twice as likely as men to develop GCA, which currently affects an estimated 200 per 100,000 people over the age of 50.

In the new study, women with biopsy-positive GCA who were between 50 and 69 years of age at time of diagnosis were given a questionnaire addressing hormonal and reproductive factors. The answers were compared statistically with those from a large population of non-GCA controls using logistic regression analysis and multivariate logistic regression analysis.

"The aim of our study was to learn more about the etiopathogenesis of GCA; [namely,] are there any indications that female sex hormones are involved? Our observations indicate that this may be so," said lead researcher Claes Nordborg, MD, PhD, of the department of pathology at Sahlgrenska University Hospital in Göteborg, Sweden.

According to the study results, women who had smoked were more than six times as likely to have GCA, compared with their counterparts who never smoked. Moreover, a reduction of 1.0 kg/m² in BMI was shown to increase the risk of developing GCA by 10%. "A low BMI implies a reduction in adipose tissue, which will have an impact on estrogen synthesis," the authors note.

Low hormone production a possible risk

Women who entered menopause before age 43 were almost four times as likely to have GCA as their counterparts who began menopause later, the study showed. The study also found that each month of breast feeding slightly increased the risk of developing GCA.

"Early menopause and extended breast feeding implies longer periods of reduced influence from female sex hormones," the authors point out. "The results may consequently indicate a relationship between low female sex hormone production and the risk of developing GCA." To confirm the results, an extended study that includes women over age 70 is needed.

Results too preliminary to draw conclusions

The study authors assert, however, that there is not enough information to specifically identify those at risk or to recommend particular treatments. "At present, there are no reliable prognostic parameters when it comes to the evaluation of risk for vascular complications in GCA. Red-flagging of high-risk patients is therefore not possible, since we do not know how to identify them," Dr. Nordborg says, adding that it is also too early to determine possible treatments. "We do not believe that any recommendations concerning treatment could be based on our observations. We did not find any support for the contention that hormone replacement therapy [would reduce] the risk of getting GCA."

Going forward, the study team is investigating the significance of various morphological phenomena as seen in temporal artery biopsies.

Reference

1. Larsson K, Mellström D, Nordborg C, Oden A, Nordborg E.  Early menopause, low body mass index and smoking are independent risk factors for developing giant cell arteritis. Ann Rheum Dis [serial online]. August 26, 2005.