Age at diagnosis of smoking-related disease

The younger individuals are when they become daily smokers, the sooner they are likely to be diagnosed with chronic obstructive pulmonary disease, heart disease or rheumatoid arthritis, according to a new study.

In the case of chronic obstructive pulmonary disease, women appeared to be more susceptible than men to the detrimental effects of smoking.

In 2000/01, the cumulative incidence of having at least one of the three diseases was highest among smokers who had started smoking daily in adolescence. By age 60, 32% of men who had become daily smokers when they were aged 13 to 17 had been diagnosed with chronic obstructive pulmonary disease or heart disease or rheumatoid arthritis. The corresponding figures were 24% for men who had become daily smokers when they were aged 18 to 22, and 14% for those who had never smoked. Among women, the estimated percentages were even higher: 41%, 29% and 17%, respectively.

Even when socio-economic status - as measured by level of education and household income - and the number of cigarettes smoked per day were taken into account, the risk of developing chronic obstructive pulmonary disease among those who started smoking when they were adolescents was three times that of those who never smoked. For young adult starters, the risk was about twice as high as for those who never smoked. And among women, the risk of being diagnosed with chronic obstructive pulmonary disease was significantly higher for those who started smoking when they were adolescents than for those who started when they were young adults.

The relationship between early smoking initiation and heart disease was similar. Adolescent starters had about twice the risk of having been diagnosed with heart disease, compared with those who never smoked. Among men - but not women - the risk compared with those who never smoked was also significantly high for young adult starters. As well, the heart disease risk for men was significantly higher among adolescent starters than among young adult starters.

Smokers also had a significantly higher risk of rheumatoid arthritis than did those who had never smoked. However, the risk was not significantly higher for adolescent starters than for young adult starters.

Note: The article uses data from the 2000/01 Canadian Community Health Survey. Daily smokers aged 35 to 64 are compared with their contemporaries who had never smoked. The smokers are divided into two groups according to the age at which they recall becoming daily smokers: 13 to 17 (adolescence) and 18 to 22 (young adulthood). Data on the presence of chronic diseases are self-reported and not independently verified, nor do they specify the nature of a condition or its severity.

The article "Age at diagnosis of smoking-related disease" is now available in Health reports, Vol. 14, no. 2 (82-003-XIE, $15/$44; 82-003-XPE, $20/$58). For more information, or to enquire about the concepts, methods or data quality of this release, contact Kathryn Wilkins (613-951-1769; kathryn.wilkins@statcan.gc.ca), Health Statistics Division, or Jiajian Chen (808-944-7426), East-West Centre, Honolulu, Hawaii.

This issue of Health reports contains two other articles. The first, "Neighbourhood low income, income inequality and health in Toronto," shows that, in the Toronto census metropolitan area, self-perceived health was significantly associated with neighbourhood low income and income inequality, even when individual low-income status and other individual characteristics were considered. This association was not found for two other health outcomes: distress and number of chronic conditions. For more information on this article, contact Feng Hou (613-951-4337; feng.hou@statcan.gc.ca), Business and Labour Market Analysis Division.

The second, "Validity of self-reported prescription drug insurance coverage," reveals that self-reports of prescription drug insurance coverage reflect substantial under-reporting among seniors and social assistance recipients, that is, respondents who were eligible for publicly funded provincial benefits. For more information on this article, contact France Bilocq (613-951-6956; france.bilocq@statcan.gc.ca), Health Statistics Division or Paul Grootendorst (616-946-3994; paul.grootendorst@utoronto.ca), Faculty of Pharmacy, University of Toronto.

For more information about Health Reports, contact Claude Graziadei (613-951-8374; claude.graziadei@statcan.gc.ca), Health Statistics Division.