Analysis of smoking behaviour among Iranian population: a cohort and period analysis.
The patterns of smoking in ageing cohorts are important to public health authorities. The aim of this study is to describe the patterns of smoking among Iranian population. Data from cross-sectional surveys of Health and Disease Survey (HDS) in Iran were utilized. Smoking was categorized as no smoker, light smoker (less than 10 cigarettes a day), moderate smokers (10 to 20 cigarettes a day), and heavy smoker (more than 20 cigarettes a day). Age group cohorts were constructed by following each age group to the next age group in two consecutive surveys. The change in smoking behavior was express as the difference of smoking prevalence and 95% confidence interval around the difference were constructed. Three birth cohorts of 1930, 1960, and 1975 were constructed among smoker and their age at initiation of smoking were assessed for the three cohorts. Smoking was more prevalent among age group 25-39 in males and age group 40-60 in females. Smoking prevalence increased in all categories of smoking behavior among male cohort of 15-25 year age-group and stayed stable afterward up to their 40's. After age 40, the prevalence of smoking decreased in heavy smokers and stayed stable in light and moderate smokers. A different pattern was seen among female smokers. Age at initiation of smoking decreased in the last decades. Among the male birth cohort of 1930, just 32.6% of smokers started smoking before age 20 compared with 48.7% in birth cohort of 1975, P value < 0.0001. Similar pattern was seen among the female smokers. The pattern of smoking in Iranian population high lights the fact that smoking behavior is highly age dependent.