Table 5 Estimated prevalence of relapse within 1 week, 1 month, 6 months, and 1 year following the longest cessation attempt according to level of cigarette consumption* and period of adolescence among adolescent smokers who ever attempted cessation

Country, study year	Age/grade range	Definition of duration of abstinence	Prevalence (%) of relapse within various time intervals following the longest cessation attempt†
Country, study year	Age/grade range	Definition of duration of abstinence	⩽1 week	⩽1 month	⩽6 months	⩽1 year
Any use (in the past month)
Early to middle adolescence
Canada, 199437	Age 10–14	Longest time you ever quit smoking	48‡§	67‡§	90‡§
United States, 1989–199074	Age 12–13	Longest time you stayed off cigarettes	15	48	88	88
Middle adolescence
United States, 1989–199074	Age 14–15	Longest time you stayed off cigarettes	14	44	89	91
Early to late adolescence
Canada, 199437	Age 10–19	Longest time you ever quit smoking	41‡§	65‡§	90‡§	94§
United States, 1989–199074	Age 12–18	Longest time you stayed off cigarettes	16‡	47‡	89‡	91‡
Middle to late adolescence
Canada, 199437	Age 15–19	Longest time you ever quit smoking	39§	65§	91§	96\|\|§
Late adolescence
United States, 1989–199074	Age 16–18	Longest time you stayed off cigarettes	17	48	89	92
Daily use (in the past week)
Early to middle adolescence
Canada, 200470	Grade 5–9	Longest time successfully stopped smoking	68	83
Daily use (in the past month)
Early to middle adolescence
Canada, 199437	Age 10–14	Longest time you ever quit smoking	73§
Early to late adolescence
Canada, 199437	Age 10–19	Longest time you ever quit smoking	49‡§	72§¶	92§	95§
Middle to late adolescence
Canada, 199437	Age 15–19	Longest time you ever quit smoking	46\|\|§	71\|\|§	93\|\|§	97\|\|§
Non-daily use (in the past month)
Early to middle adolescence
Canada, 199437	Age 10–14	Longest time you ever quit smoking	30**§	54**§	82**§
Early to late adolescence
Canada, 199437	Age 10–19	Longest time you ever quit smoking	26‡§	52‡§	86‡§	92§
Middle to late adolescence
Canada, 199437	Age 15–19	Longest time you ever quit smoking	18\|\|**§	45\|\|**§	85\|\|**§

*Any use in the past month was defined operationally as “smoked ⩾1 cigarette in the past 30 days”, except in Allen et al74 where it was defined as “smoked in the past 30 days”; daily use in the past week was defined operationally as: “smoked cigarettes on each of the 7 days preceding data collection”; daily use in the past month was defined operationally as: “smoked⩾1 cigarette each day in the past 30 days”; non-daily use in the past month was defined operationally as: “smoked ⩾1 cigarette in the past 30 days, but not daily”.
†Findings for the duration of the longest cessation attempt were usually reported on an ordinal rather than on a continuous scale. Summary estimates could only be calculated where the responses were scaled similarly across multiple studies. The prevalence of relapse categories reported here were derived by combining multiple ordinal categories.
‡Excluded from the calculation of summary estimate because complete stratum-specific estimates were available for this study.
§Estimated among the subgroup of adolescents who had smoked ⩾100 cigarettes in their lifetime.
||Excluded from the calculation of summary estimate because a more inclusive estimate was available.
¶Additional data were reported on the prevalence of relapse within 1 month following the longest cessation attempt according to the frequency of daily consumption among adolescents aged 10–19 who had consumed ⩾100 cigarettes in their lifetime and who had ever tried to quit smoking, as follows: 74 (16–20 cigarettes per day), 52 (⩽5 cigarettes per day).
**Estimate does not include quit attempts of ⩽1 day due to high sampling variability in this category. For 10–14 year olds, between 9–17% quit for ⩽1 day; for 15–19 year olds, between 5–7% quit for ⩽1 day.