Smoking: If I Quit, Will it Make a Difference? Is it Ever Too Late?


Here is a link to an excellent article, Asthma and COPD: Clearing the Air by Alan Kaplan, MD, CCFP(EM), presented to physicians and health care professionals at Primary Care Today, Toronto, May 2005.  A key element in this article is the classic Fletcher-Peto Curve, showing the effect of smoking continuation or discontinuation on the decrease in Forced Expiratory Volume at one second (FEV1) over time. FEV1 is one of the major indications of the level of severity of COPD.

Here is a link to the article. If it does not open for you, copy and paste it on your web browser.


We encourage you to read the entire article, but it is quite long and some of it is written for health care professionals. If you would rather not read the entire text, here are some tips from Breathing Better, Living Well on what to focus on and look for in this excellent article and graph.



Page 89 – Read the first two paragraphs and “John’s case.”


Page 90 – Look at Table 1, “COPD or Asthma” to see the differences between the two and how your    doctor might settle upon a diagnosis.

Read the information in the two pink boxes.


Page 91 – Read the “Treatment Goals of Asthma” in the pink box.

Were you wondering what ever happened to John? Read “John’s Diagnosis.”


Page 92 – The Fletcher Peto curve is a long-standing and extremely helpful tool in understanding the general relationship of long-term cigarette smoking, lung function and life expectancy. It is based on FEV1, the volume of air you are able to force out in the first second of exhalation in a pulmonary function test.

PLEASE NOTE: Although this is an excellent general indication of lung function and smoking over time, each case is different and you are strongly encouraged to take this table to your next appointment and discuss it, along with your own case, with your physician. The following guidelines to understanding the curve were prepared by Jane M. Martin, CRT.


Š      The top black line represents those who never come in contact with cigarette smoke at all. Notice that the person would still have high lung function at age 100.


Š      The brown section represents those who smoke regularly and are susceptible to its effects. Note how a person in this category could be expected to begin to have a rapid decrease in lung function in his or her 50’s and 60’s.


Š      The pink section shows how stopping smoking, even at age 65, slows the rate of loss of lung function. A person in this category can expect to breathe better for longer, even though there is already significant lung damage.


Š      The yellow section represents those who stop smoking at age 45. Note the significantly higher  lung function and life span of those in this group. According to this graph, a person who quits smoking at age 45 can be expected to not reach disability with breathing until about age 90.