Table 2.
Validity evaluation of self-reported current cigarette smoking prevalence within the second survey.
| Second Survey | Self-Reported Questionnaire | |||||||
|---|---|---|---|---|---|---|---|---|
| Total (N = 1059) | Boys (N = 444) | Girls (N = 615) | ||||||
| Second Survey | Current Smoker N (%) |
Current Smoker N (%) |
Current Smoker N (%) |
|||||
| Yes | No | Yes | No | Yes | No | |||
| Urine cotinine a | Current smoker | Yes | 87 (91.6) | 8 (8.4) | 75 (94.9) | 4 (5.1) | 12 (75.0) | 4 (25.0) |
| No | 25 (2.6) | 939 (97.4) | 18 (4.9) | 347 (95.1) | 7 (1.2) | 592 (98.8) | ||
| Validity indicator | Value | 95% CI | Value | 95% CI | Value | 95% CI | ||
| Sensitivity (%) | 91.6 | 84.1, 96.3 | 94.9 | 87.5, 98.6 | 75.0 | 47.6, 92.7 | ||
| Specificity (%) | 97.4 | 96.2, 98.3 | 95.1 | 92.3, 97.1 | 98.8 | 97.6, 99.5 | ||
| Kappa | 0.823 | 0.765, 0.882 | 0.842 | 0.778, 0.906 | 0.677 | 0.497, 0.857 | ||
Abbreviation: CI, confidence interval. a Cutoff value of urinary cotinine concentration: 50 ng/mL.