Table 2.
Characteristics of the study participants according to quartile of mean PPD.
| Mean PPD | |||||
|---|---|---|---|---|---|
| Q1 (Low) n = 412 | Q2 n = 412 | Q3 n = 412 | Q4 (High) n = 414 | P value | |
| At baseline examination | |||||
| Men, % | 31.8 | 38.3 | 43.4 | 56.0 | <0.001 |
| Age, years | 59.7 ± 11.4 | 61.3 ± 10.4 | 62.1 ± 10.9 | 65.0 ± 11.3 | <0.001 |
| Occupation, % | |||||
| White-collar workers | 33.7 | 31.6 | 27.9 | 28.3 | 0.001* |
| Blue-collar workers | 12.1 | 13.3 | 18.4 | 22.7 | |
| Unemployed, homemakers, and part-time workers | 54.1 | 55.1 | 53.6 | 49.0 | |
| Diabetes mellitus, % | 10.4 | 14.1 | 16.3 | 21.3 | <0.001 |
| Body mass index | 22.3 ± 3.3 | 23.1 ± 3.3 | 23.4 ± 3.4 | 23.9 ± 3.3 | <0.001 |
| Physically active, % | 49.8 | 48.8 | 50.2 | 42.3 | 0.056 |
| Brinkman index, % | |||||
| 0 (Never smokers) | 68.2 | 64.1 | 61.4 | 46.4 | <0.001* |
| 1–399 (Ex-smokers) | 13.8 | 12.6 | 10.2 | 8.9 | |
| 400–799 (Ex-smokers) | 5.3 | 8.3 | 7.0 | 11.8 | |
| ≥800 (Ex-smokers) | 5.1 | 4.1 | 6.8 | 13.3 | |
| 1–399 (Current smokers) | 2.7 | 3.4 | 4.1 | 2.9 | |
| 400–799 (Current smokers) | 3.2 | 4.9 | 4.9 | 10.1 | |
| ≥800 (Current smokers) | 1.7 | 2.7 | 5.6 | 6.5 | |
| Alcohol intake, % | |||||
| Never | 37.1 | 34.7 | 32.3 | 37.0 | 0.778* |
| Former | 12.6 | 13.8 | 13.1 | 12.1 | |
| Current | 50.2 | 51.5 | 54.6 | 51.0 | |
| FEV1, L | 2.3 ± 0.6 | 2.3 ± 0.6 | 2.3 ± 0.6 | 2.3 ± 0.6 | 0.561 |
| FEV1% predicted, % | 96.5 ± 12.9 | 95.7 ± 14.6 | 96.0 ± 13.5 | 92.7 ± 14.1 | <0.001 |
| FEV1/FVC %, % | 76.9 ± 5.5 | 77.2 ± 5.4 | 77.0 ± 5.1 | 76.0 ± 5.7 | 0.015 |
| At follow-up examination | |||||
| Decline in FEV1, mL/3years | 62.1 ± 144.4 | 72.8 ± 168.3 | 73.4 ± 160.6 | 76.5 ± 160.7 | 0.210 |
| Rapid decline in FEV1 (≥160 mL/3years), % | 21.6 | 25.5 | 24.5 | 30.7 | 0.006 |
Quartiles for mean probing pocket depth were <1.29, 1.30–1.62, 1.63–1.98, ≥1.99 mm.
PPD = probing pocket depth; FEV1 = forced expiratory volume in one second; FVC = forced vital capacity.
Categorical variables were expressed as percentages.
Continuous variables were expressed as means ± SDs.
*Tested using chi-square test.