Abdominal aortic aneurysm events in postmenopausal womenBMJ 2008; 337 doi: https://doi.org/10.1136/bmj.a1894 (Published 15 October 2008) Cite this as: BMJ 2008;337:a1894
- 1Vascular Surgery Research Group, Imperial College, Charing Cross Campus, London W6 8RP
- 2School of Surgery, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, WA 6959, Australia
Smoking is the dominant risk factor for abdominal aortic aneurysm in both men and women. In the linked cohort study from the women’s health initiative, Lederle and colleagues assess the potential risk factors for clinically relevant abdominal aortic aneurysm in 161 808 postmenopausal women. They show that current smokers have a four times greater risk of abdominal aortic aneurysm events and all those who have smoked more than 100 cigarettes have a twofold increase in risk, even if they have given up smoking.1
Smoking increases the relative risk of abdominal aortic aneurysm four times in both men and women, and the risk for ischaemic heart disease or peripheral arterial disease is increased twofold.2 Previous studies have associated both early onset of smoking and total duration of smoking with heightened risk of abdominal aortic aneurysm, although in many studies these associations were based on aortic diameter rather than clinical events. The effect of passive smoking has not been reported. In addition, the benefits of stopping smoking are apparent more quickly with regard to ischaemic heart disease than abdominal aortic aneurysm.3
Recent studies in Europe show that although the number of male smokers is decreasing, the number of female smokers continues to increase and has not yet peaked.4 The epidemiology of abdominal aortic aneurysms raises several questions. If abdominal aortic aneurysm follows a lifetime of smoking, is the incidence of abdominal aortic aneurysm in women less than in men because, in the past, fewer women than men have smoked, and smoking became popular in women about three decades after it became popular in men? Or, do oestrogens slow changes in aortic disease, so that women are relatively protected from abdominal aortic aneurysm until after the menopause and develop aneurysms later than men? The role of the sex hormones (oestrogens, progestogens, and androgens) has yet to be clarified.
Lederle and colleagues’ current study is one of the first to look at the effect of hormone replacement therapy on the development of clinically relevant abdominal aortic aneurysms in women.1 The apparent protection from abdominal aortic aneurysm for women taking hormone replacement therapy merits further investigation, even though previous smaller studies from the women’s health initiative indicated that therapy with oestrogen alone may increase the risk of abdominal aortic aneurysm.5 Experimental studies have indicated that oestrogens decrease the risk of aortic aneurysm by reducing aortic matrix metalloproteinase expression and other mechanisms,6 and that androgens may increase the risk by angiotensin receptor dependent mechanisms.7
Intriguingly, Lederle and colleagues confirmed that the negative association between diabetes and abdominal aortic aneurysm seen in men is also present in women.1 However, this association may be less useful for improving the management of abdominal aortic aneurysm than the association seen with sex.
Although abdominal aortic aneurysm is less common in women, the standardised mortality ratio after elective repair of abdominal aortic aneurysm is higher in women than in men, and age standardised mortality is increasing faster in women than in men.8 9 In addition, abdominal aortic aneurysm has a worse prognosis in women than in men.6 10 In women, aneurysms rupture at smaller diameters, the rate of intervention is lower, and mortality after intervention may be higher.
So, what are the implications of the results on clinical practice and policy? Getting women to stop smoking is a public health priority. The problem of high mortality from abdominal aortic aneurysm in men is being tackled by population screening programmes focused on men.11 In the United States screening is in place for women with a strong family history of abdominal aortic aneurysm, but if the incidence of this disorder in women continues to rise, population screening for women who have smoked or continue to smoke might need to be considered.
Cite this as: BMJ 2008;337:a1894
Competing interests: None declared.
Provenance and peer review: Commissioned; not externally peer reviewed.