Quitting smoking after age 40 has major health benefits
Although the health risks have been known for more than 50 years, smoking remains the number one preventable cause of disability and early death in developed countries.
Smoking is a high-risk behaviour, and helping a smoker to quit is one of the most important interventions a doctor can make to improve a patient's health. Indicators for smoking are included in QOF2, see table 2, attached.
A new study from The Netherlands sheds further light on the impact of different forms of smoking (cigarettes, cigars and pipe) on life expectancy and quality of life.
The Zutphen Study followed a random sample of 1,373 middle-aged men for 40 years, from 1960 to 2000, performing five-yearly assessments of their smoking and health status.
The repeated measurements allowed a comprehensive picture to emerge of each man's smoking habit as it changed throughout his life. Information was also collected on potential confounders, such as diet, alcohol intake and social status, so that these factors could be adjusted for in the analysis.
The key outcome measures were difference in life expectancy at age 40, and difference in number of disease-free years of life, between those who continued to smoke and those who quit or never smoked. For disease-free years of life, survival until the age of onset of myocardial infarction, stroke, diabetes mellitus or cancer was used.
Unsurprisingly, smoking was found to be strongly associated with cardiovascular disease, lung cancer and COPD. The higher the number of cigarettes smoked per day and the longer the duration of smoking, the higher the mortality. Average levels of cigarette smoking reduced life expectancy at age 40 by about seven years, whereas heavy cigarette smoking (>30 per day) reduced life expectancy by about nine years. In addition, cigarette smokers lost an average of about six disease-free life years. Cigar or pipe smoking had a similar, though slightly smaller, impact, reducing life expectancy at age 40 by about five years, with an additional loss of about five disease-free life years.
On the positive side, quitting smoking improved life expectancy. Stopping at age 40 increased life expectancy by about five years on average, and at age 60 by about three years. This supports the findings of the British Doctors Study, which showed that there are benefits of quitting smoking at any age.1
The figures in this study are averages, so for those smokers who succumb to a smoking-related disease (and half eventually do) a higher number of years of life will usually be lost. This study also reminds us that not only does smoking cause premature death, it also robs people of productive, disease-free life.
Streppel MT, Boshuizen HC, Ocké MC, et al. Mortality and life expectancy in relation to long-term cigarette, cigar and pipe smoking: The Zutphen Study. Tob Control 2007;16(2):107-13 doi:10.1136/tc.2006.017715Reviewer
Dr Kevin Lewis
Former GP, Clinical Director of Smoking Cessation, Shropshire County Primary Care Trust