Table 3. Association between misclassification of smoking status by self-report and characteristics in all subjects and actual current smokers.
| Characteristics | Overall subjects | p-value | Actual current smokers identified by urine cotinine test | p-value | |||
|---|---|---|---|---|---|---|---|
| No. (%) | Misclassification | No. (%) | Misclassificationa | ||||
| Total | 445 (100.0) | 29.66 (25.40–33.92) | 228 (100.0) | 57.02 (50.54–63.49) | |||
| Age (years) | |||||||
| ≤ 29 | 55 (12.4) | 12.73 (3.63–21.82) | 0.029b | 32 (14.0) | 21.88 (6.73–37.02) | < 0.001b | |
| 30–39 | 165 (37.1) | 30.30 (23.22–37.39) | 91 (39.9) | 52.75 (42.29–63.20) | |||
| 40–49 | 146 (32.8) | 33.56 (25.81–41.31) | 72 (31.6) | 68.06 (57.02–79.09) | |||
| ≥ 50 | 79 (17.8) | 32.91 (22.32–43.50) | 33 (14.5) | 78.79 (64.07–93.51) | |||
| Working duration (years) | |||||||
| ≤ 9 | 206 (46.3) | 22.33 (16.60–28.06) | 0.007b | 114 (50.0) | 39.47 (30.36–48.58) | < 0.001b | |
| 10–19 | 120 (27.0) | 35.00 (26.34–43.66) | 58 (25.4) | 70.69 (58.62–82.76) | |||
| ≥ 20 | 119 (26.7) | 36.97 (28.17–45.78) | 56 (24.6) | 78.57 (67.48–89.66) | |||
| Exercise | |||||||
| Proper (≥ 3 times/week) | 327 (73.5) | 29.05 (24.11–34.00) | 0.639 | 163 (71.5) | 57.06 (49.38–64.74) | 0.985 | |
| Improper (≤ 2 times/week) | 118 (26.5) | 31.36 (22.86–39.85) | 65 (28.5) | 56.92 (44.56–69.29) | |||
| Alcohol | |||||||
| Proper (≤ 2 cups/day on average) | 384 (86.3) | 30.73 (26.09–35.36) | 0.217 | 188 (82.5) | 61.70 (54.69–68.71) | 0.002b | |
| Improper (> 2 cups/day on average) | 61 (13.7) | 22.95 (12.09–33.81) | 40 (17.5) | 35.00 (19.55–50.45) | |||
| Obesity | |||||||
| Underweight/normal (BMI < 23.0) | 138 (31.0) | 31.16 (23.33–38.98) | 0.353 | 69 (30.3) | 60.87 (49.06–72.68) | 0.555 | |
| Overweight (23.0 ≤ BMI < 25.0) | 129 (29.0) | 23.81 (17.25–32.36) | 62 (27.2) | 51.61 (38.82–64.41) | |||
| Obesity (BMI ≥ 25.0) | 178 (40.0) | 32.02 (25.10–38.94) | 97 (42.5) | 57.73 (47.72–67.74) | |||
| Diseasesc | |||||||
| Yes | 43 (9.7) | 41.86 (26.50–57.22) | 0.065 | 19 (8.3) | 94.74 (83.68–105.79) | 0.001b | |
| No | 402 (90.3) | 28.36 (23.93–32.78) | 209 (91.7) | 53.59 (46.77–60.41) | |||
The p-value calculated by χ2 test.
BMI: body mass index; CI: confidence interval.
aMisclassification in actual smoker means false-negative in self-report; bMean p-value is statistically significant; cDiseases include hypertension, diabetes, dyslipidemia, stroke, and heart disease.