Hello sevenfoot,
Thanks for asking this question. Before I start, let me congratulate
you on quitting smoking. As a physician, these are things I like to
hear. Here is your question:
“Did smoking cause permanent damage to my health / increase my chance
of smoking-related illnesses later in life?”
The short answer is yes - prior smokers are at higher risk of some
diseases than never smokers. The data from the studies are outlined
below.
As we know, the most common and important (i.e. causes of mortality)
smoking-related diseases include atherosclerotic vascular disease
(heart attack and stroke), cancer (primarily lung), and chronic
obstructive pulmonary disease (COPD). Let me discuss the effects of
smoking cessation on each of these disorders.
1) Cardiac (risk of heart attack and stroke)
The cardiac risks associated with cigarette smoking diminish
relatively soon after smoking cessation and continue to fall with
increasing length of time since quitting (2). Similar benefits have
been noted in patients with cardiovascular disease. In one study of
564 postinfarction patients, for example, the risk of recurrent
infarction fell by 50 percent within one year of smoking cessation and
normalized to that of nonsmokers within two years (3).
The risk of ischemic stroke also decreases over time after smoking
cessation. In one series of middle-aged women, for example, the excess
risk among former smokers largely disappeared two to four years after
cessation (4).
The benefits of smoking cessation are equivalent in young and old
patients. In one study of 1893 patients with CHD who were older than
55 years, the mortality after six year follow-up was significantly
higher among patients who continued to smoke compared to those who
stopped (relative risk 1.7 – i.e. mortality was 70% higher in smokers)
(5). The benefits were equivalent in those aged 55 to 64 and over age
65 and were the same as observed among comparable patients aged 34 to
54.
2) Lung cancer
Lung cancer is the most common cause of cancer death in the United
States and throughout the world. Cigarette smoking is estimated to be
responsible for approximately 87 percent of cases of lung cancer,
including 90 percent of cases in men and 79 percent of cases in
women.(6)
Smoking cessation clearly decreases the risk of lung cancer among
former smokers compared with current smokers (7). Studies have
attempted to quantify the magnitude of the reduction in risk of lung
cancer following cessation of smoking. Estimates of the extent of
risk reduction over time vary from 20 to 90 percent, depending upon
the duration of abstinence, with a progressive decline in risk
associated with an increasing duration of abstinence (7).
The studies show that former smokers who had been abstinent for more
than 15 years had an 80 to 90 percent reduction in risk of lung cancer
compared to current smokers (7).
However, lung cancer risk remains higher than in the never smoker,
even after prolonged periods of complete abstinence from smoking. It
has been estimated that former smokers continue to have a 10 to 80
percent greater risk than nonsmokers (8).
3) Chronic obstructive pulmonary disease (COPD)
Cigarette smoking is responsible for 80 percent of the risk of
developing chronic bronchitis, and it is associated with a doubling or
tripling of the rate of decline in FEV1 (a measure of lung function)
and a 2 to 20 fold increase in the risk of death from COPD.
Smoking cessation reduces the accelerated rate of decline of FEV1
found in smokers compared to non-smokers. What this means is that
after smoking cessation, the rate of decline will revert to that of a
non-smoker. However, since there was damage done by smoking, the
total lung function will still be less than that of a never-smoker
(1).
Please use any answer clarification before rating this answer. I will
be happy to explain or expand on any issue you may have.
Thanks,
Kevin, M.D.
Internet search strategy:
No internet search engine was used in this research. All sources were
from objective physician-written and peer reviewed sources.
Bibliography:
1) Samet, JM. Health benefits of smoking cessation. Clin Chest Med
1991; 12:669.
2) The health benefits of smoking cessation. A report of the Surgeon
General, Washington, DC: U.S. Department of Health and Human Services.
1990 DHHS Publication (CDC) 90-8416.
3) Wilhelmsson, C, Vedin, JA, Elmfeldt, D, et al. Smoking and
myocardial infarction. Lancet 1975; 1:415.
4) Kawachi, I, Colditz, GA, Stampfer, MJ, et al. Smoking cessation and
the decreased risk of stroke in women. JAMA 1993; 269:232.
5) Hermanson, B, Omenn, GS, Kronmal, RA, Gersh, BJ. Beneficial
six-year outcome of smoking cessation in older men and women with
coronary artery disease. Results from the CASS registry. N Engl J Med
1988; 319:1365.
6) American Cancer Society. Cancer facts and figures - 1995. American
Cancer Society, Atlanta 1995. p. 1
7) The Health Benefits of Smoking Cessation: A Report of the Surgeon
General. US Dept of Health and Human Services, Washington 1990.
8) Newcomb, PA, Carbone, PP. The health consequences of smoking:
cancer. Med Clin North Am 1992; 76:305.
9) Rennard et al. Overview of smoking cessation. UptoDate, 2002. |
Clarification of Answer by
kevinmd-ga
on
26 Dec 2002 06:13 PST
Hello,
Thanks for your clarification request.
You asked the following:
“Is there any research on such a small number of cigarettes smoked? It
is hard to believe there is potential for lifelong health damage from
<200 cigarettes. Can you address this at all?”
I am not able to cite studies specifically addressing the permanent
health consequences after quitting light smoking. Consider the
following studies addressing light smoking:
“"There is an amazingly large risk of developing blood clots in the
heart, or mortality, from smoking as few as three to five cigarettes a
day," Dr. Eva Prescott, head of the study, told Reuters on Thursday.”
http://www.siliconvalley.com/mld/siliconvalley/news/3869032.htm
“Previous studies on "light" smokers also showed that smoking a
relatively small number of cigarettes daily was hazardous to one's
health, but in these previous studies a cutoff of 10 - 20 cigarettes
per day was used. This is the first study to document that even a
very small number of cigarettes per day is a problem . . . Cigarette
smokers who convince themselves that "cutting back" is good enough are
sadly mistaken. Even a few cigarettes a day puts you at a significant
medical disadvantage. The only safe way to deal with cigarettes is to
avoid them altogether.”
http://heartdisease.about.com/library/weekly/aa081802a.htm
Here is the conclusion from that study:
“CONCLUSIONS: Smoking as little as 3-5 grams of tobacco per day or not
inhaling the smoke was shown to carry a significantly increased risk
of developing MI and of all cause mortality with higher RR found in
women than in men. The study emphasises the importance of recognising
that even very limited tobacco consumption has detrimental health
effects.”
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12177089&dopt=Abstract
One can infer that since light smoking has health consequences,
quitting will help reduce the risk.
If you looked at my answer above – regarding the cardiovascular
effects of smoking cessation:
“In one study of 564 postinfarction patients, for example, the risk of
recurrent infarction fell by 50 percent within one year of smoking
cessation and normalized to that of nonsmokers within two years (3).”
“In one series of middle-aged women, for example, the excess risk
among former smokers largely disappeared two to four years after
cessation (4).”
This suggests that the risk of stroke or heart attack after quitting
approaches that of non-smokers after several years.
However, regarding lung disease:
“The studies show that former smokers who had been abstinent for more
than 15 years had an 80 to 90 percent reduction in risk of lung cancer
compared to current smokers (7).”
“However, lung cancer risk remains higher than in the never smoker,
even after prolonged periods of complete abstinence from smoking. It
has been estimated that former smokers continue to have a 10 to 80
percent greater risk than nonsmokers (8).”
“However, since there was damage done by smoking, the total lung
function will still be less than that of a never-smoker (1).”
The damage to the lung is permanent - but you are correct in saying
that the effect is cumulative (i.e. heavy smokers do more damage than
light smokers). However, even with light smoking – although I cannot
cite hard numbers (due to the lack of studies) – the studies infer
that the risk is still slightly greater than non-smokers.
Thanks,
Kevin, M.D.
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