Table 2. Association of the validity of self-reported smoking status with subjects' characteristics.
| Characteristics | No. (%) | Sensitivity | Specificity | PPV | NPV | |
|---|---|---|---|---|---|---|
| Total | 445 (100.0) | 42.98 (36.51–49.46) | 99.08 (97.80–100.36) | 98.00 (95.21–100.79) | 62.32 (57.18–67.46) | |
| Age (years) | ||||||
| ≤ 29 | 55 (12.4) | 78.13 (62.98–93.27) | 100.00 | 100.00 | 76.67 (60.60–92.73) | |
| 30–39 | 165 (37.1) | 47.25 (36.80–57.71) | 97.30 (93.51–101.08) | 95.56 (89.29–101.82) | 60.00 (51.11–68.89) | |
| 40–49 | 146 (32.8) | 31.94 (20.91–42.98) | 100.00 | 100.00 | 60.16 (51.39–68.94) | |
| ≥ 50 | 79 (17.8) | 21.21 (6.49–35.93) | 100.00 | 100.00 | 63.89 (52.52–75.26) | |
| p-valuea | < 0.001b | 0.274 | 0.481 | 0.360 | ||
| Working duration (years) | ||||||
| ≤ 9 | 206 (46.3) | 60.53 (51.42–69.64) | 98.91 (96.75–101.07) | 98.57 (95.72–101.42) | 66.91 (58.90–74.92) | |
| 10–19 | 120 (27.0) | 29.31 (17.24–41.38) | 98.39 (95.16–101.61) | 94.44 (82.72–106.17) | 59.80 (50.13–69.48) | |
| ≥ 20 | 119 (26.7) | 21.43 (10.34–32.52) | 100.00 | 100.00 | 58.88 (49.40–68.35) | |
| p-valuea | < 0.001b | 0.627 | 0.471 | 0.362 | ||
| Exercise | ||||||
| Proper (≥ 3 times/week) | 327 (73.5) | 42.94 (35.26–50.62) | 98.78 (97.08–100.48) | 97.22 (93.33–101.11) | 63.53 (57.58–69.48) | |
| Improper (≤ 2 times/week) | 118 (26.5) | 43.08 (30.71–55.44) | 100.00 | 100.00 | 58.89 (48.53–69.25) | |
| p-valuec | 0.986 | 0.420 | 0.375 | 0.435 | ||
| Alcohol | ||||||
| Proper (≤ 2 cups/day on average) | 384 (86.3) | 38.30 (31.29–45.31) | 98.98 (97.56–100.40) | 97.30 (93.51–101.08) | 62.58 (57.16–68.00) | |
| Improper (> 2 cups/day on average) | 61 (13.7) | 65.00 (49.55–80.45) | 100.00 | 100.00 | 60.00 (42.93–77.07) | |
| p-valuec | 0.002b | 0.643 | 0.399 | 0.766 | ||
| Obesity | ||||||
| Underweight/normal (BMI < 23.0) | 138 (31.0) | 39.13 (27.32–50.94) | 98.55 (95.66–101.44) | 96.43 (89.10–103.76) | 61.82 (52.60–71.04) | |
| Overweight (23.0 ≤ BMI < 25.0) | 129 (29.0) | 48.39 (35.59–61.18) | 100.00 | 100.00 | 67.68 (58.30–77.05) | |
| Obese (BMI ≥ 25.0) | 178 (40.0) | 42.27 (32.26–52.28) | 98.77 (96.31–100.36) | 97.62 (92.81–102.43) | 58.82 (50.45–67.20) | |
| p-valuea | 0.557 | 0.632 | 0.611 | 0.382 | ||
| Diseasesd | ||||||
| Yes | 43 (9.7) | 5.26 (−5.79–16.32) | 100.00 | 100.00 | 57.14 (41.53–72.75) | |
| No | 402 (90.3) | 46.41 (39.59–53.23) | 98.96 (97.52–100.41) | 97.98 (95.16–100.80) | 63.04 (57.57–68.50) | |
| p-valuec | < 0.001b | 0.618 | 0.887 | 0.462 | ||
Values are presented as percentage (95% CI).
BMI: body mass index; CI: confidence interval; PPV: positive predictive value; NPV: negative predictive value.
aThe p-value calculated by Kruskal-Wallis test; bMean p-value is statistically significant; cThe p-value calculated by Mann-Whitney test; dDiseases include hypertension, diabetes, dyslipidemia, stroke, and heart disease.