Objective: To assess the role of cardiovascular risk factors, measured at the time of diagnosis, in the pathogenesis of giant cell (temporal) arteritis (GCA).
Methods: Four hundred new patients with GCA or polymyalgia rheumatica (PMR) and population-based, individually age- and sex-matched controls were included in this multicenter, prospective case-control study. Each participant was evaluated by review of the medical history and by clinical and laboratory assessments.
Results: Among women, smoking was associated with a 6-fold increase in risk (P = 0.00006, 95% confidence interval [95% CI] 2-17), heavy smoking with a 17-fold increase in risk, and previous atheromatous disease with a 4.5-fold increase in risk (P = 0.0003, 95% CI 2-11) of GCA in both the biopsy-positive and biopsy-negative GCA groups; only smoking appeared to be a risk factor for PMR in women (odds ratio 3.64, 95% CI 1.07-12.40). Among men, no risk factor was found to be significant.
Conclusion: Smoking and previous arterial disease were independently associated with GCA in women. In order to avoid matching bias, risk factors for diseases with an unbalanced sex distribution should be studied separately in each sex, using a sex-matched, case-control study design.