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 An abdominal aortic aneurysm (AAA) occurs when the aorta, the main
vessel supplying blood to the lower body, becomes enlarged or bulges
due to weakening of its walls. The problem can be treated if it’s
detected - but if a tear or rupture happens, only about one in five
people will survive, according to the National Library of Medicine.
“We already knew that smoking is a very strong risk factor for AAA,”
said lead author Dr. Weihong Tang of the University of Minnesota in
Minneapolis. “This study adds to the literature by reporting AAA
lifetime risk from a community-based cohort with long follow-up,”
Tang told Reuters Health by email.
The researchers used data from more than 15,000 middle-aged people
who were at risk of developing AAA based on an initial assessment
between 1987 and 1989. The participants made three subsequent visits
for exams and assessments through 1998.
Nearly 6,000 people were still alive between 2011 and 2013 and
underwent an ultrasound exam at a fifth assessment visit then.
Over the 22-year follow-up period, there were 590 diagnosed,
ruptured or repaired AAAs. In 2011, the ultrasound scans found 75
more cases that had gone undetected.
Based on these results, researchers calculated that for participants
who began the study, 1 in 17 would go on to develop an AAA,
including 1 out of every 9 current smokers and 1 out of 12 former
smokers.
People who had quit smoking within eight years of the final
assessment in 2001-2003 had higher risk of aneurysm than those who
had quit earlier, according to the results in Arteriosclerosis,
Thrombosis and Vascular Biology.
“An AAA is a slow and gradually expanding process, and most commonly
goes without any symptoms,” said Dr. Otto Stackelberg of the
Karolinska Institute in Solna, Sweden, who was not part of the new
study.
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“These results should not be interpreted as if it is OK to start
smoking since the risk of AAA eventually decreases anyway if you
quit,” Stackelberg told Reuters Health by email. “Nonetheless,
results in the current study are encouraging in the sense that it is
never too late to quit, given that those who ceased to smoke had, on
average, 29 percent lower risk of developing AAA during their
lifetime as compared with those who continued to smoke.”
There was a steep increase in risk for female smokers, as for male
smokers, but the U.S. Preventive Services Task Force only recommends
ultrasound screening for current or former male smokers between the
ages of 65 and 75, the authors note.
“AAA affects about 5 to 9 percent of Americans who are 65 years or
older,” Tang said. “Smoking may act through activation of chronic
inflammation, which in turn activates enzymes that degrade elastin
and collagen fibers of the aortic wall.”
SOURCE: http://bit.ly/2fG9L3r Arteriosclerosis, Thrombosis and
Vascular Biology, online November 10, 2016.
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