Cigarette Smoking Across Life from 1946 to 2018: Harmonisation of Four British Birth Cohort Studies

Background and AimsTobacco smoking has declined dramatically in the many high-income countries over the past seventy years. Studies that have mapped this trend have relied on repeat cross-sectional or retrospectively measured smoking data which has limitations regarding accurate measurement, inclusion of early smokers, and capturing of within-person change over time. Here, we (1) introduce a new resource detailing harmonisable smoking data in four British birth cohort studies spanning 1946-2018 and (2) use this data to document age and cohort changes in smoking. MethodsWe used prospectively and longitudinally measured smoking data in four British Birth Cohort Studies, born 1946, 1958, 1970 and 2000/02, respectively, to examine changes in the prevalence of daily smoking and cigarettes smoked per day between cohorts and within cohorts over the life course in males and females combined and stratified by sex. ResultsThe prevalence of smoking and the average number of cigarettes smoked by daily smokers declined between each successive cohort. Males smoked more and with greater intensity than females, on average, though sex differences were smaller in latter cohorts. Within a cohort, the prevalence and intensity of smoking peaked in early adulthood (< age 30y) and declined thereafter; participants who continued to smoke daily, smoked fewer cigarettes as they grew older. ConclusionSmoking prevalence and cigarette consumption declined substantially between cohorts born across the latter half of the twentieth and early twenty-first centuries. The British Birth Cohorts represent a unique and largely underutilized resource for investigating trends in smoking across life (prenatal to old age) and by year of birth (1946-2001), including changes in the determinants, correlates, and consequences of smoking. We provide syntax and information on items on smoking in these cohorts to catalyse future research, also available at: osf.io/54w6q.