Table 3.
Crude and adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) for dental caries in relation to smoking in the household of 20,703 schoolchildren, RYUCHS, Japan
| Prevalence (%) | Crude PR (95% CI) | Adjusted PR1 (95% CI) | |
|---|---|---|---|
| Decayed and/or filled teeth | |||
| Smoking in household | |||
| Never | 8080/10192 (79.3) | 1.00 | 1.00 |
| Former | 1574/1888 (83.4) | 1.05 (1.03, 1.08) | 1.03 (1.00, 1.05) |
| Current <152 | 4403/5215 (84.4) | 1.07 (1.05, 1.08) | 1.04 (1.02, 1.05) |
| Current ≥152 | 2915/3408 (85.5) | 1.08 (1.06, 1.10) | 1.04 (1.03, 1.06) |
| P for trend | < 0.0001 | < 0.0001 | |
| Pack-years of passive smoking in household | |||
| None | 8080/10192 (79.3) | 1.00 | 1.00 |
| 0.1-2.9 | 2827/3352 (84.3) | 1.06 (1.05, 1.08) | 1.03 (1.02, 1.05) |
| 3.0-6.9 | 2935/3490 (84.1) | 1.06 (1.04, 1.08) | 1.03 (1.01, 1.05) |
| ≥7.0 | 3130/3669 (85.3) | 1.08 (1.06, 1.09) | 1.04 (1.03, 1.06) |
| P for trend | < 0.0001 | < 0.0001 | |
| Decayed teeth | |||
| Smoking in household | |||
| Never | 4394/10192 (43.1) | 1.00 | 1.00 |
| Former | 944/1888 (50.0) | 1.16 (1.10, 1.22) | 1.06 (1.02, 1.11) |
| Current <152 | 2797/5215 (53.6) | 1.24 (1.20, 1.29) | 1.10 (1.06, 1.13) |
| Current ≥152 | 1889/3408 (55.4) | 1.29 (1.24, 1.33) | 1.10 (1.07, 1.14) |
| P for trend | <0.0001 | <0.0001 | |
| Pack-years of passive smoking in household | |||
| None | 4394/10192 (43.1) | 1.00 | 1.00 |
| 0.1-2.9 | 1717/3352 (51.2) | 1.19 (1.14, 1.24) | 1.06 (1.03, 1.10) |
| 3.0-6.9 | 1943/3490 (55.7) | 1.29 (1.24, 1.34) | 1.13 (1.10, 1.17) |
| ≥7.0 | 1790/3669 (53.7) | 1.25 (1.20, 1.29) | 1.11 (1.08, 1.15) |
| P for trend | <0.0001 | <0.0001 | |
| Filled teeth | |||
| Smoking in household | |||
| Never | 6974/10192 (68.4) | 1.00 | 1.00 |
| Former | 1305/1888 (69.1) | 1.01 (0.98, 1.04) | 1.00 (0.97, 1.04) |
| Current <152 | 3623/5215 (69.5) | 1.02 (0.99, 1.04) | 1.01 (0.99, 1.04) |
| Current ≥152 | 2362/3408 (69.3) | 1.01 (0.99, 1.04) | 1.01 (0.98, 1.04) |
| P for trend | 0.18 | 0.31 | |
| Pack-years of passive smoking in household | |||
| None | 6974/10192 (68.4) | 1.00 | 1.00 |
| 0.1-2.9 | 2376/3352 (70.9) | 1.04 (1.01, 1.06) | 1.03 (1.01, 1.06) |
| 3.0-6.9 | 2369/3490 (67.9) | 0.99 (0.97, 1.02) | 0.99 (0.96, 1.02) |
| ≥7.0 | 2545/3669 (69.4) | 1.01 (0.99, 1.04) | 1.01 (0.98, 1.03) |
| P for trend | 0.55 | 0.93 | |
1 Adjustment for sex, age, region of residence, toothbrushing frequency, use of fluoride, sugar intake, and paternal and maternal educational level.
2 Number of cigarettes smoked in the household per day.