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The Daily. Friday, June 22, 2001

Impact of smoking on life expectancy and disability

Smokers spend a larger proportion of their lives coping with functional disabilities than do non-smokers, and they are far more likely to die prematurely, according to a study on the relationship between smoking and disability-free life expectancy.

The study, which analyzes data from the National Population Health Survey, found that smoking not only reduces the number of years that a person may hope to live, it also has a negative impact on their quality of life. Smoking has been associated with a variety of chronic conditions ranging from bronchitis to asthma to high blood pressure.

Of every 100 non-smoking men aged 45 in 1995, about 90 will survive to the age of 65, and 55 will still be living at the age of 80.

However, of every 100 male smokers aged 45, 80 will survive to the age of 65, and fewer than 30 will still be living at the age of 80.

Among women, the percentage of survivors is higher for both smokers and non-smokers. However, the consequences of tobacco use are just as evident. Among women who were aged 45 in 1995, about 70% of non-smokers will survive to the age of 80, compared with only about 40% of those who smoked.

Data also show that non-smokers are expected to live a higher proportion of their life without any disability. Among both men and women, two-thirds of non-smokers will survive without any disability to the age of 65, compared with less than half of smokers. In addition, 25% of male non-smokers and 30% of female non-smokers who live to the age of 80 will have no disability, compared with less than 10% for both men and women who smoke.

Note to readers This release is based on one of five studies in the annual publication Report on the demographic situation in Canada, available today. The data for the article on the impact of smoking came from the longitudinal component of the National Population Health Survey, conducted by Statistics Canada since 1994. The survey gathers detailed information on the state of physical and mental health, functional capabilities, use of and access to health care, chronic health problems and life habits and behaviour related to health. The information is reported by the respondents themselves during a telephone interview. The sample used in this study is representative of the Canadian population aged 45 and older living in private households and in health care establishments in 1994. In this study, smokers and non-smokers are defined as follows: a smoker is a respondent who reports either that he or she smoked daily, smoked occasionally but was a former daily smoker, or a formerly smoked daily but had stopped within the past five years. A non-smoker is a respondent who never smoked, who smokes only occasionally, or who smoked daily but stopped more than five years ago.

Significant differences in life expectancy between smokers and non-smokers

Men who were aged 45 in 1995 could expect to live another 32.9 years, while women of that age could expect to live for another 37.7 years. However, there are major differences in life expectancy between smokers and non-smokers.

A male smoker aged 45 in 1995 could expect to live only another 28.1 years, or seven years less than a male non-smoker, who could expect to live another 35.5 years. A female smoker aged 45 in 1995 could expect to live another 30.5 years, or more than 10 years less than a female non-smoker, who could expect to live another 40.8 years.

Even at age 65, differences in life expectancy between smokers and non-smokers remain important. Almost six years of life expectancy separate men who smoke from those who do not, and the gap is 8.5 years among women. Tobacco use, therefore, has a major impact on life expectancy, eliminating close to one-quarter of the remaining years that a woman aged 45 could expect to live.

Several factors could explain these differences in mortality based on smoking. Smokers suffer more often than others from several diseases at the same time. Non-smokers often adopt certain healthy lifestyle behaviours, such as regular physical activity, moderate alcohol consumption and better eating habits.

Disability-free life expectancy

This study also calculated disability-free life expectancy at various ages. Analysis shows that the negative impact of tobacco use is not limited to mortality. Tobacco use also has a negative impact on an individual's quality of life.

For example, a male smoker who was aged 45 in 1995 could expect to live another 18 years without some form of related disability. However, a male non-smoker could expect to live another 25 years, or seven years longer, without disability. Among women, non-smokers could live eight more years without disability than smokers.

In short, 95% of the additional years that a male non-smoker can expect to live over a smoker will be spent without disability. Not only will a smoker, on average, die younger than a non-smoker, as other studies have already shown, but the smoker will also be more likely to be limited or dependent in his or her activities of daily living at a younger age than a non-smoker.

Non-smokers can expect not only to live longer than smokers, and to live longer without disability, but also to spend a smaller percentage of their life with a disability. The lower incidence of disability among the non-smoking population, combined with their increased chance of regaining their independence, means that they will spend a larger proportion of their total life expectancy without disability. This finding is especially remarkable given that the risk of acquiring a disability increases with age and non-smokers enjoy a longer life than smokers.

Blended families: A step further in family life

A second article in this report traces the emergence of the "blended family," and explores the features of stepfamilies that make them most likely to become blended families. Blended family is the term used here to describe stepfamilies with a common child.

According to this article, which used data from the General Social Survey and the National Longitudinal Survey of Children and Youth, more and more children are having to adjust to the presence of a stepparent. The article found that one or both parents of almost one-half of the children of separated couples had entered new unions two to three years after the separation. Furthermore, although almost one-half of all stepfamilies become blended families, little is known about these children and the stability of their families.

The lower the age of the mother and of the youngest child in the stepfamily, the more likely a birth is to occur to the new union. The number of children already present has a negligible effect on the decision to have another child in a stepfamily.

Finally, the children of blended families were more at risk of family breakdown than were children of intact families.

This report contains three other studies. One is a comprehensive review of the Canadian demographic situation and a description of recent trends in population growth, fertility and migration. Another examines the impact of leading causes of death on changes in life expectancy in people aged 60 and over. The third analyses the links between demographic changes and the economic well-being of families with preschool-age children.

The 2000 edition of Report on the demographic situation in Canada (91-209-XPE, $31) is available today.

For more information, or to enquire about the concepts, methods or data quality of this release, contact Alain Bélanger (613-951-2326; fax: 613-951-2952; belaala@statcan.gc.ca), Demography Division.