Table 4.
Generalized Estimating Logistic Regressions for Quit History Variables (at Wave t) Predicting Cessation Outcomes (at Wave t + 1) for the Full Seven-Wave Sample
| Quit attempt | Sustained abstinence (among attempters) | Overall outcome (sustained abstinence) | ||||
|---|---|---|---|---|---|---|
| N observations/N individuals | 29,682/13,417 | 9,794/6,519 | 28,493/12,819 | |||
| Total percent achieving the outcome | 37.0 | 21.1 | 7.3 | |||
| Percentage of participants achieving each of the cessation outcomes | ||||||
| Time since last quit attempt ended (%) | ||||||
| Within last month | 67.3 | 16.0 | 10.5 | |||
| 32–181 days ago | 60.7 | 16.9 | 9.8 | |||
| 182 days to 1 year ago | 49.0 | 18.6 | 8.6 | |||
| More than 1–2 years ago | 36.2 | 22.4 | 7.5 | |||
| More than 2–3 years ago | 31.8 | 26.2 | 7.7 | |||
| More than 3–ago | 27.5 | 27.9 | 7.0 | |||
| Over 5 years ago | 19.9 | 29.2 | 5.3 | |||
| No previous quit attempts | 17.0 | 27.7 | 4.2 | |||
| Longest quit attempt ever made (%) | ||||||
| More than 6 months | 43.1 | 27.7 | 11.1 | |||
| More than 1–6 months | 42.8 | 20.4 | 8.2 | |||
| More than 1 week to 1 month | 40.1 | 13.5 | 5.1 | |||
| Up to 1 week | 33.1 | 12.5 | 3.9 | |||
| No quit attempts ever made | 17.0 | 27.7 | 4.2 | |||
| Odds ratios (OR) and 95% confidence intervals (CI) for concurrent generalized estimating equations (never quit excluded) | ||||||
| N observations/N individuals | 25,051/11,357 | 9,104/6,007 | 23,961/10,817 | |||
| OR | 95% CI | OR | 95% CI | OR | 95% CI | |
| Time since last quit attempt ended | ||||||
| Within last month | Ref | p < .00001 | Ref | p < .00001 | Ref | p < .00001 |
| 32–181 days ago | 0.79 | 0.71–0.87 | 1.13 | 0.95–1.35 | 0.98 | 0.83–1.17 |
| 182 days to 1 year ago | 0.55 | 0.50–0.61 | 1.39 | 1.16–1.67 | 0.98 | 0.82–1.17 |
| More than 1–2 years ago | 0.32 | 0.29–0.35 | 1.58 | 1.30–1.92 | 0.77 | 0.64–0.93 |
| More than 2–3 years ago | 0.28 | 0.25–0.32 | 1.91 | 1.52–2.41 | 0.77 | 0.63–0.95 |
| More than 3–5 years ago | 0.25 | 0.22–0.28 | 2.16 | 1.72–2.72 | 0.74 | 0.60–0.91 |
| More than 5 years ago | 0.16 | 0.14–0.18 | 2.25 | 1.83–2.76 | 0.54 | 0.44–0.65 |
| Longest quit attempt ever made | ||||||
| More than 6 months | Ref | p < .00001 | Ref | p < .00001 | Ref | p < .00001 |
| More than 1–6 months | 0.88 | 0.82–0.95 | 0.74 | 0.65–0.85 | 0.71 | 0.63–0.80 |
| More than 1 week to 1 month | 0.80 | 0.73–0.87 | 0.49 | 0.41–0.59 | 0.45 | 0.39–0.53 |
| Up to 1 week | 0.67 | 0.61–0.73 | 0.48 | 0.40–0.58 | 0.40 | 0.34–0.48 |
Note. Sustained abstinence is for at least 6 months; overall outcome = sustained abstinence among all smokers. All analyses are adjusted for age, sex, education, income, ethnic minority status, marital status, cohort, interwave interval, Heaviness of Smoking Index, baseline smoking frequency, and self-efficacy. Analysis predicting the sustained abstinence outcome among those who tried is also adjusted for use of stop-smoking medications since baseline and method of quitting (cut down or cold turkey) followed on the last quit attempt at the outcome wave (wave t + 1). The full table of results including associations with the control variables may be obtained on request from the corresponding author. Significance (p) values next to the reference category represent the overall effect across categories.