Trends in smoking by birth cohort for births between 1940 and 1975: a reconstructed cohort analysis of the 1990 Ontario Health Survey.
BACKGROUND
Smoking patterns have changed markedly over the past 70 years. Previous studies have shown that examination of smoking patterns within birth cohorts can identify important changes in tobacco adoption and cessation. This paper examines temporal trends in the prevalence of smoking and the age of smoking adoption and cessation for birth cohorts born between 1940 and 1975.


METHODS
The underlying data were obtained from the Ontario Health Survey (conducted in 1990), which used a multistage stratified area sampling strategy to obtain interviews on 29,843 people age 12 or older. Self-reported smoking histories were used as the basis for a reconstructed cohort analysis of prevalence rates. A life events methodology was employed to examine the age at starting smoking and the time of smoking cessation.


RESULTS
There has been a steady drop in peak smoking prevalence for men. This trend appears to be continuing among the most recent cohorts. However, for women, peak smoking prevalence increased until the 1960 birth cohort, after which time the peak prevalence has been dropping. Prevalence of smoking was much higher for men then for women among the earlier birth cohorts but, by the 1960 cohort, the prevalence for men and women was essentially the same. Examination of the age of smoking onset reveals that there was a statistically significant interaction between sex and birth cohort on the relative risk of starting smoking. The rate of smoking cessation has increased uniformly across all birth cohorts among both men and women.


CONCLUSIONS
This study confirms recent trends in smoking reduction and provides no evidence to suggest a diminution of the effect. Trends in recent birth cohorts of women are encouraging. There is a clear need for public health initiatives directed at older children and teenagers in order to further reduce the onset of smoking. Efforts to prohibit advertising directed toward minors, sponsorship of sporting and cultural events, and the sale of tobacco to minors should receive high priority.
Birkett
N J
NJ
Department of Epidemiology and Community Medicine, University of Ottawa, Ontario, Canada. nbirkett@zeus.med.uottawa.ca
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D002648:Child; D015988:Cohort Effect; D015331:Cohort Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D015995:Prevalence; D012189:Retrospective Studies; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology / Q000639:trends*; D016540:Smoking Cessation / Q000706:statistics & numerical data*; D016019:Survival Analysis