Smoking may increase lifetime risk for abdominal aortic aneurysms, according to data from a long-term prospective study.
“Although risk factors for AAA incidence have been reported in several prospective, epidemiological studies, data are scare on the lifetime risk of AAA, which is defined as the cumulative incidence of AAA between an index age and death, because lifetime risk estimation requires substantial follow-up duration,” Weihong Tang, MD, PhD, associate professor of epidemiology and community health at the University of Minnesota, and colleagues wrote. “Although smoking is the most important risk factor for AAA, there are limited data on how smoking cessation contributes to the reduction of AAA risk in smokers.”
Tang and colleagues analyzed 15,792 participants from the ARIC cohort study from visit 1 in 1987-1989 and followed up in 2011-2013. Longitudinal smoking status was determined using smoking behavior at visit 1 to visit 4 (1996-1998).
Researchers identified 590 incident clinical AAAs using hospital discharge diagnoses, Medicare outpatient diagnoses or death certificates through 2011. In the 5,911 participants still alive in 2011, abdominal ultrasounds were conducted in 2011-2013 and 75 asymptomatic AAAs were identified.
At age 45 years, the lifetime risk for clinical AAA was 5.6% (95% CI, 4.8-6.1). Lifetime risk was higher in men (8.2%; 95% CI, 6.9-9), white participants (6.5%; 95% CI, 5.6-7.1), current smokers (10.5%; 95% CI, 7.7-11.7) and those who had 15.3 to 33.9 pack-years of smoking (9%; 95% CI, 6.5-10.4) and 34 to 243 pack-years of smoking (11.1%; 95% CI, 8.7-12.4). The lifetime risk for rupture or medical intervention was 1.6% (95% CI, 1.2 to 1.8).
Participants who quit smoking after visit 1 for at least 3 to 8 years had a 29% lower lifetime risk for AAA than current smokers. The quitters still had a higher risk than those who had never smoked or quit before baseline, according to Tang and colleagues.
The U.S. Preventive Services Task Force recommends a one-time ultrasound screening for AAA in male smokers aged 65 to 75 years and selective screening for male nonsmokers in the same age group, but makes no recommendations for women the same age and smoking status. According to the researchers, lifetime risk for clinical AAA in women who were current smokers (8.2%; 95% CI, 4.8-9.9) was similar to men who were former smokers (8.1%; 95% CI, 6.4-9.3) and higher than in men who were never smokers (3.9%; 95% CI, 1.8-5.2).
“Our data also indicate that physicians may need to pay similar attention in monitoring female current smokers for the occurrence of AAA as to male ever smokers after they pass middle age,” Tang and colleagues wrote. “By all means, the best preventive strategy to reduce AAA risk in smokers is to stop smoking.” – by Cassie Homer
Disclosure: The researchers report no relevant financial disclosures.