Among 24 healthy young adults in the study, the combination of smoking and
caffeine consumption temporarily increased stiffness in the aorta -- the main
artery carrying blood from the heart to the rest of the body -- more than either
caffeine or smoking did alone.
In fact, the effect of the cigarette-caffeine combo was more than just the
sum of the effects of each, according to findings published in the Journal of
the American College of Cardiology.
This means that tobacco and caffeine may act interact and work in a
synergistic manner to harm the arteries over the long run, the study authors
conclude.
Indeed, a second phase of the study, involving 160 healthy adults, found that
those who were regular smokers and caffeine consumers showed the greatest
stiffness in the aorta. This suggests that the combination does pose a
particular threat to the arteries over time, according to lead study author Dr.
Charalambos Vlachopoulos of the Athens Medical School in Greece.
The aorta is the largest artery in the body, and stiffness in the large
arteries contributes to high blood pressure and forces the heart to work harder
to meet the body's needs. Over time, this can lead to complications such as
heart attack and stroke.
The main message from the new findings, Vlachopoulos told Reuters Health, is,
not surprisingly, that people who smoke should quit.
For those who have yet to quit, he advised avoiding heavy caffeine
consumption -- and not having a cup of coffee along with that cigarette.
In addition, Vlachopoulos noted, older adults and those with high blood
pressure may be especially vulnerable to the combined effects of tobacco and
caffeine.
For the first phase of their study, Vlachopoulos and his colleagues used
non-invasive measures to estimate aortic stiffness in 24 healthy young adults
who were regular smokers and caffeine consumers.
The measures were taken before and after each of four conditions: smoking one
cigarette; smoking a cigarette after taking the equivalent of two coffee cups'
worth of caffeine; puffing on a "sham" cigarette; having a sham cigarette after
taking phony caffeine pills.
Aortic stiffness, the researchers found, was greatest after the
cigarette-caffeine combination, and the results of the larger, population study
-- where participants ranged in age from 18 to 60 -- confirmed a similar one-two
punch in those who regularly smoked and drank coffee.
According to Vlachopoulos, the immediate effects that caffeine and smoking
had on the aorta may have to do with the release of certain hormones and central
nervous system chemicals that affect artery function, blood pressure and heart
rate.
Whether this explains the long-term harm linked to the caffeine-cigarette
combo is less clear, he added, because researchers don't yet know how regular
caffeine intake affects the health and function of the arteries over time.
SOURCE: Journal of the American College of Cardiology, November 2, 2004.
