Nicotine May Be Bad for Arteries
Study Links Nicotine Exposure, Even From Low-Nicotine Cigarettes, to Hardening of Arteries in Mice
Sept. 14, 2007 -- New research shows that nicotine from cigarette smoke may
promote hardening of the arteries (atherosclerosis), even with low-nicotine
Atherosclerosis makes heart attacks more likely.
The new study focuses on mice, not people. But the researchers say the
findings may help explain why smoking
is a risk factor for heart disease.
"The best thing to do is quit" smoking, says Daniel Catanzaro, PhD,
of Cornell University's Weill Medical College, in a news release.
That's easy to say but often hard to do. If you're one of the many smokers
who want to quit
smoking, experts say it may take several attempts to kick the habit, but
it's worth the effort.
Catanzaro and colleagues studied five groups of male mice.
One group of mice was exposed to smoke from cigarettes made for research
purposes (and which aren't on the market) that deliver 1 milligram of nicotine
Another group of mice was exposed to smoke from Quest 1 cigarettes, which
deliver 0.6 milligram of nicotine per cigarette.
A third group of mice was exposed to smoke from Quest 3 cigarettes, which
deliver 0.05 milligram of nicotine per cigarette.
A fourth group of mice was exposed to smoke from Eclipse cigarettes, which
deliver 0.2 milligram of nicotine per cigarette.
The fifth group of mice wasn't exposed to any cigarette smoke.
Obviously, mice don't smoke cigarettes. So the researchers placed the mice
in a cage and piped in cigarette smoke for an hour a day (10-12 cigarettes
burned per session) for eight to 12 weeks. The "nonsmoking" mice spent
the same amount of time in that cage, but without any smoke exposure.
Nicotine Study's Results
The mice exposed to smoke from cigarettes with higher levels of nicotine
developed more plaque buildup in their arteries than the mice exposed to smoke
from low-nicotine cigarettes.
But the mice exposed to smoke from low-nicotine cigarettes still had more
plaque buildup in their arteries than mice not exposed to tobacco smoke.
Plaque buildup can lead to atherosclerosis, which can lead to heart
"While our study seems to suggest that low-nicotine cigarettes are safer
[than higher-nicotine cigarettes], we also know that smokers adjust their
smoking habits to maintain their levels of nicotine," Catanzaro says in a
"In other words, if you switch to a low-nicotine product, you will
probably increase the number of cigarettes you smoke, or change the way you
smoke to get more nicotine out of each cigarette," he explains.
The study has some limits. The mice were only exposed to smoke for an hour a
day, but people tend to smoke throughout the day, and the researchers can't be
certain that cigarettes' tar (or other chemicals) didn't affect the results.
The study only featured nicotine from cigarettes, not other sources.
Catanzaro and colleagues call for further studies on the topic.