Etiologic factors in renovascular fibromuscular dysplasia

Abstract

The role of several factors that have been suggested as being of etiologic importance in renovascular fibromuscular dysplasia was examined in a case-control study of 33 patients with angiographically demonstrated fibromuscular dysplasia and 61 renal transplant donor control subjects with normal renal arteries. The factors studied included use of oral contraceptive agents or markers of sex hormone dysfunction, mechanical stress to the renal artery wall, human lymphocytic antigen (HLA) type, cigarette smoking, history of hypertension for more than 5 years, and family history of cardiovascular disease. The risk of fibromuscular dysplasia was significantly (p=0.003) increased (odds ration= 4.1, 95% confidence interval=1.5-10.9) among cigarette smokers. A significant (p<0.001) dose response relation was noted between cigarette use and the risk of fibromuscular dysplasia developing (odds ratio=8.6 for those who had smoked more than 10 pack-years). Personal history of hypertension more than 5 years was also associated (odds ratio=5.0, 95% confidence interval=1.1-22.8) with a significantly (p=0.036) increased risk for the development of fibromuscular dysplasia. HLA-DRw6 antigen was more common in the 33 fibromuscular dysplasia patients than in the 61 renal transplant donor control subjects (odds ratio=3.00, p=0.067) or a second group of 934 ambulatory control subjects (odds ratio=2.51, p=0.031). Adjustment for cigarette smoking increased the odds ratio to 5.0 (95% confidence interval=1.3-19.6). There was a positive though not statistically significant (odds ratio=1.7, p=0.175) association noted between family history of cardiovascular disease and fibromuscular dysplasia. No evidence of an etiologic association between the occurrence of fibromuscular dysplasia and prior oral contraceptive use, endogenous sex hormone abnormality, or increase in renal mobility was noted. Our results suggest that cigarette smoking and genetic predisposition are of etiologic importance in fibromuscular dysplasia. However, they fail to support the putative role of other previously suggested causal factors such as oral contraceptive use and excessive renal mobility.