Age at diagnosis of smoking-related disease

This study assesses the relationship between the age of daily smoking initiation and the age at diagnosis of chronic obstructive pulmonary disease (COPD), heart disease and rheumatoid arthritis.

The data are from the 2000/01 Canadian Community Health Survey (CCHS). The sample for the analysis consisted of 34,144 respondents aged 35 to 64 living in private households in the provinces and territories.

The life table approach was used to estimate the cumulative incidence of smoking-related disease. Cox proportional hazards regression models were used to estimate the relative risks of disease by the age when daily smoking began.

For both sexes, the younger the individuals were when they became daily smokers, the sooner they were diagnosed with COPD, heart disease or rheumatoid arthritis. Even when education, household income and number of cigarettes smoked per day were taken into account, adolescent starters were at increased risk of these diseases, compared with never-smokers.