Everyone is now aware of the connection between
cigarette smoking and lung cancer. How many also realize that the
smoker is three to four times more likely to experience heart attack
than the nonsmoker, and that the attack is more likely to be fatal?
The risk increases proportionally with the number of cigarettes
smoked and is particularly high in those under the age of 50. The
risk of sudden cardiac death increases more than tenfold in men
and fivefold in women who smoke.
According to the American Academy of Pediatrics,
more than 3,000 children and teenagers in the United States start
to smoke each day. Furthermore, while there has been a sharp decline
in the number of men in the 20-to-25 age bracket who start the smoking
habit, there has been a sharp increase in new women smokers in the
same age bracket. If the trend continues, soon we can expect that
more women than men will smoke. The British medical authorities
have come up with the sobering statistic that of every thousand
young adults who smoke, 250 will die of a smoking-related disease.
Although there is growing opposition in the West to tobacco advertising
and its targeting of the young, the developing countries have yet
to take a similar stance; unless they do, they will face a similar
epidemic of lung cancer and heart disease. The tobacco industry
is now targeting the developing countries, and apparently with considerable
success. Will these nations eventually have to face a problem of
Tobacco smoke contains more than 2,000 known
substances, including nicotine, carbon monoxide, nitrogen dioxide,
benzine, formaldehyde, and hydrogen cyanide. Many of these compounds
are capable of damaging the endothelial lining of the coronary arteries
and thereby provoking atherosclerosis. Probably the two major harmful
compounds are nicotine and carbon monoxide. The nicotine in cigarette
smoke is highly addictive. It is released into the bloodstream within
seven seconds of inhaling the smoke and almost immediately triggers
the release of adrenaline and a related substance called noradrenaline.
These two hormones, which are produced by the adrenals, two small
glands just above the kidney, prepare the body for "fight or
flight." As a result, blood pressure rises and heart rate goes
up, increasing the heart muscle's requirements for oxygen. Unfortunately
however, this demand is thwarted by the action of the other substance
in tobacco smoke, carbon monoxide, which is also the principal poisonous
ingredient in car exhaust fumes. In large doses, carbon monoxide
kills by displacing all the oxygen in red blood cells. Actually,
hemoglobin, the protein in the red cell that carries oxygen, prefers
carbon monoxide and, given the choice, is 200 times more likely
to pick it up than oxygen. You can see the paradox. Nicotine increases
the heart muscle's oxygen requirements, and carbon monoxide makes
sure that those requirements are not met.
If the coronary arteries are already narrowed
and the blood supply to the heart limited as a result of atherosclerosis,
smoking makes matters worse. Anginal sufferers who smoke experience
pain at a much lower level of exertion than nonsmokers. Even in
the absence of coronary atherosclerosis, heavy smoking may cause
heart attacks. There are reports of young heavy-smoking adults who
have suffered a heart attack and yet on subsequent investigation
are found to have normal coronary arteries. The mechanism is a shutdown
of the coronary artery due to a spasm provoked by exposure to nicotine.
In susceptible individuals, nicotine can cause life-threatening
irregularities of the heartbeat. Sudden cardiac death is thereby
probably another hazard for smokers. A number of investigations
have also established that smokers have "sticky" blood
and are liable to develop clots in their arteries, particularly
the coronary vessels or the vessels in the leg. Finally, it has
been noted that habitual smokers have lower levels of the protective
HDL-C. Since a high HDL-C is felt to be one of the major mechanisms
that protects young women from coronary disease, this might explain
who women who smoke seem to have lost that protection.
It is extremely hard for most people to give
up smoking. As an ex-smoker myself, I sympathize with anyone trying
to quit. Experts in the field have said that in some ways addiction
to cigarettes is as strong as, if not stronger than, addiction to
heroin. The acute physical withdrawal symptoms may not be so severe,
but apparently the craving is never quite extinguished. Many individuals
who stopped smoking for 20 or even 30 years have started again after
a few casual cigarettes. After 30 years of working with cardiac
patients at the Toronto Centre, we are now experiencing this phenomenon.
Admittedly the numbers are small, but some people who were enrolled
in our program in the late 1960s, and who stopped smoking after
their heart attack, have started again after 20 years. To be honest,
I have to say that if somebody were to offer me a perfectly safe
cigarette now (and such a cigarette is nowhere in sight), even 30
years after quitting I would be tempted to start smoking again !
There is no safe alternative to quitting.
Low-tar, low-nicotine filter cigarettes have been found to be just
as dangerous as their predecessors, since habitual smokers will
continue to get their boost of nicotine by taking deeper more frequent
puffs and smoking the cigarette right down to its filter. Pipe and
cigar smokers are at slightly less risk than those who smoke cigarettes,
but this is apparently not the case for former cigarette smokers.
Having once learned to inhale from a cigarette, smokers invariably
apply the same practice to a pipe or cigar.
How quickly after you quit can you expect
to reduce your risk for a heart attack? Nicotine is quickly cleared
from the body ( which is why you experience early withdrawal symptoms).
Carbon monoxide takes about 24 hours to clear, but by then its ill
effects will have gone. One to two weeks after stopping, the risk
starts to decrease, and a number of studies have demonstrated that
it reaches almost the level of a nonsmoker at the end of one to
Danger to Nonsmokers
In recent years, there has been increasing recognition of the dangers
to nonsmokers of sidestream smoke, that is, the smoke that escapes
into the air from the burning end of the cigarette for all to inhale,
smokers and nonsmokers alike. In fact, this danger has been the
major impetus for the banning of smoking in public places. Actually,
sidestream smoke contains a higher concentration of nicotine, carbon
monoxide, and other pollutants than exhaled ( mainstream) smoke.
Obviously, the danger to the nonsmoker is greater in confined areas.
A Scottish study looked at the effect on a nonsmoker living with
a spouse who smoked. More than 15,000 men and women were followed
up for an average of 11.5 years. The nonsmoking spouses of smokers
had two and a half times the incidence of lung cancer and twice
the incidence of heart disease compared with the nonsmoking spouses
of nonsmokers. Further American and British studies have confirmed
that exposure to second-hand smoke can increase the risk of heart
attack by 20% - 30%.
CCRF would like to thank Dr. T. Kavanagh for his contribution to the Website.
The articles, on the Cardiac Health Foundation of Canada website, are presented with the understanding that the Foundation is providing information only and not rendering medical advise. Please check with your family physician, specialist or health care professional before implementing any of the ideas expressed in these articles.
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