How much unsuccessful quitting activity is going on among adult smokers? Data from the International Tobacco Control Four Country cohort survey

Abstract

Aims: To document accurately the amount of quitting, length of quit attempts and prevalence of plans and serious thought about quitting among smokers.

Design: We used longitudinal data from 7 waves of the International Tobacco Control Policy Evaluation Four Country Survey (ITC-4). We considered point-prevalence data and cumulative prevalence over the 7 years of the study. We also derived annual estimates of quit activity from reports of quit attempts starting only within more recent time-frames, to control for biased recall.

Setting: Australia, Canada, the United Kingdom and the United States.

Participants: A total of 21,613 smokers recruited across seven waves.

Measurements: Reported life-time quit attempts, annual quit attempts, length of attempts, time since last attempt started, frequency of aborted attempts, plans to quit and serious thought about quitting.

Findings: Around 40.1% (95% CI: 39.6-40.6) of smokers report attempts to quit in a given year and report an average of 2.1 attempts. Based on free recall, this translates to an average annual quit attempt rate of 0.82 attempts per smoker. Estimates derived only from the preceding month to adjust for recall bias indicate an annual rate of approximately one attempt per smoker. There is a high prevalence of quit-related activity, with more than a third of smokers reporting thoughts or actions related to quitting in a given month. More than half the surveyed smokers eventually succeeded in quitting for at least 1 month, and a majority of these for over 6 months.

Conclusions: Smokers think a great deal about stopping and make many unsuccessful quit attempts. Many have been able to last for extended periods and yet they still relapsed. More attention needs to be focused on translating quit-related activity into long-term abstinence.

Figure 1

Cumulation of quit attempts over time for participants retained for different time periods, from a base of reporting ever having made an attempt at baseline (solid line) or reporting an attempt in the previous year (dashed line). Successful quitters (those currently quit at the time of being surveyed) were included and considered as having made a quit attempt. Error bars represent 95% confidence intervals.

Figure 2

Estimated annual quit attempt rate per smoker for wave 7, based on reported quit attempts starting during different time periods. The reference point at 0.81 is the average reported number of quit attempts based on straight recall for wave 7. Participants quit at the time of the survey but for under 24 hours or under 7 days were excluded from the denominator for the analyses including only attempts lasting at least 24 hours or at least 7 days, respectively. In all analyses, unsuccessful quit attempts spanning the time period of interest (starting before it and ending after it) were excluded. Note that it is not possible to account for multiple attempts by the one individual in these estimates, so accuracy diminishes with longer timeframes.

Figure 3

Prevalence of quit related activity within different time periods for smokers in wave 7 (recontacted sample). A quit attempt was defined as a quit attempt starting within the given period of one month (left columns) or since the last survey date, being approximately 12 months (right columns).