Prevalence (95% CI) | 95% Prediction interval | N studies | N participants | Heterogeneity | P Egger test | |||
---|---|---|---|---|---|---|---|---|
H (954% CI) | I2 (95% CI) | P value | ||||||
Current smokers at study initiation | 38.1 (24.7–52.6) | 1.5–87.4 | 8 | 14 446 | 15.7 (14.2–17.3) | 99.6 (99.5–99.7) | < 0.0001 | 0.458 |
Current smokers at study completion | 35.6 (6.6–72.5) | 0.0–100 | 4 | 8312 | 24.2 (21.7–27.0) | 99.8 (99.8–99.9) | < 0.0001 | 0.321 |
Former smokers at study initiation | 21.4 (15.1–28.5) | 3.1–49.8 | 8 | 25 125 | 11.7 (10.4–13.2) | 99.3 (99.1–99.4) | < 0.0001 | 0.528 |
Former smokers at study completion | 17.6 (5.1–35.5) | NA | 2 | 1358 | 6.4 | 97.5 (93.9–99.0) | < 0.0001 | NA |
Never smokers at study initiation | 28.6 (20.3–37.8) | 4.0–63.8 | 8 | 25 125 | 14.0 (12.6–15.5) | 99.5 (99.4–99.6) | < 0.0001 | 0.930 |
Never smokers at study completion | 6.1 (4.8–7.6) | NA | 1 | 1062 | NA | NA | NA | NA |
Shifting from never to current smoking during study | 2.1 (0.9–3.6) | NA | 2 | 1518 | 1.7 | 65.9 (0.0–92.3) | 0.087 | NA |
Shifting from former to current smoking during study | 1.5 (0.6–2.9) | NA | 1 | 456 | NA | NA | NA | NA |
Stopped smoking during the study (shifting from current to former smoker) | 10.5 (7.2–14.4) | 0.3–31.8 | 4 | 2191 | 2.6 (1.8–4.1) | 85.5 (64.2–94.1) | 0.0001 | 0.520 |
Stayed in the “never smoking” category | 10.1 (3.0–20.5) | NA | 2 | 1439 | 5.0 | 96.0 (88.7–98.6) | < 0.0001 | NA |
Tried to quit smoking but failed | 7.1 (4.4–10.3) | NA | 1 | 296 | NA | NA | NA | NA |
Willed to quit smoking but did not initiate any quitting attempt | 0.4 (0.0–1.3) | NA | 1 | 456 | NA | NA | NA | NA |