Table 3.
Odds ratios (ORs) and 95% confidence intervals (CIs) of nasopharyngeal carcinoma (NPC) associated with oral health among never smokers in southern China (2010–2014).
| Variable | Cases (n=1117) |
Controls (n=1213) |
Minimally adjusted OR |
Fully adjusted OR |
||
|---|---|---|---|---|---|---|
| No. | % | No. | % | (95% CI) * | (95% CI) † | |
|
Number of teeth lost after age 20 years |
||||||
| None | 601 | 53.8 | 623 | 51.4 | 1.0 (ref.) | 1.0 (ref.) |
| 1 – 3 | 297 | 26.6 | 327 | 27.0 | 0.97 (0.79, 1.18) | 0.97 (0.79, 1.19) |
| 4 – 13 | 174 | 15.6 | 195 | 16.1 | 0.98 (0.76, 1.27) | 0.98 (0.76, 1.28) |
| 14+ | 45 | 4.0 | 68 | 5.6 | 0.76 (0.50, 1.16) | 0.71 (0.46, 1.11) |
| P for trend | 0.24 | 0.16 | ||||
|
Age at first tooth loss (years) ‡ |
||||||
| ≥ 50 | 74 | 14.3 | 108 | 18.3 | 1.0 (ref.) | 1.0 (ref.) |
| 40 – 49 | 94 | 18.2 | 135 | 22.9 | 0.82 (0.54, 1.25) | 0.94 (0.61, 1.46) |
| 30 – 39 | 127 | 24.6 | 156 | 26.4 | 0.87 (0.56, 1.35) | 0.92 (0.58, 1.45) |
| 20 – 29 | 149 | 28.9 | 164 | 27.8 | 0.89 (0.56, 1.40) | 0.90 (0.56, 1.45) |
| unknown | 72 | 14.0 | 27 | 4.6 | - | - |
| P for trend | 0.82 | 0.69 | ||||
| Denture wearing | ||||||
| No | 949 | 85.0 | 1031 | 85.0 | 1.0 (ref.) | 1.0 (ref.) |
| Yes | 168 | 15.0 | 182 | 15.0 | 1.06 (0.83, 1.34) | 1.06 (0.83, 1.35) |
| Number of filled teeth | ||||||
| None | 889 | 79.6 | 1011 | 83.4 | 1.0 (ref.) | 1.0 (ref.) |
| 1 – 3 | 170 | 15.2 | 158 | 13.0 | 1.21 (0.95, 1.53) | 1.28 (1.00, 1.64) |
| ≥ 4 | 58 | 5.2 | 44 | 3.6 | 1.43 (0.96, 2.15) | 1.61 (1.06, 2.44) |
| P for trend | 0.06 | 0.02 | ||||
|
Frequency of brushing teeth (times/day) |
||||||
| ≤ 1 | 676 | 60.5 | 606 | 50.0 | 1.0 (ref.) | 1.0 (ref.) |
| ≥ 2 | 434 | 38.9 | 604 | 49.8 | 0.58 (0.49, 0.69) | 0.63 (0.52, 0.76) |
| Irregular | 7 | 0.6 | 3 | 0.2 | - | - |
|
Frequency of oral discomfort while eating |
||||||
| Never or hardly ever | 763 | 68.3 | 814 | 67.1 | 1.0 (ref.) | 1.0 (ref.) |
| Occasionally | 256 | 22.9 | 310 | 15.6 | 0.89 (0.73, 1.08) | 0.91 (0.75, 1.12) |
| Often | 88 | 7.9 | 82 | 6.8 | 1.18 (0.85, 1.62) | 1.15 (0.83, 1.60) |
| Unknown | 10 | 0.9 | 7 | 0.6 | - | - |
|
Avoidance of some foods due to oral problems |
||||||
| Never | 789 | 70.6 | 801 | 66.0 | 1.0 (ref.) | 1.0 (ref.) |
| Ever | 328 | 29.4 | 412 | 34.0 | 0.82 (0.68, 0.98) | 0.83 (0.69, 1.00) |
Adjusted for sex, age (5-year categories), and residential area (Zhaoqing, Wuzhou, or Guiping/Pingnan).
Adjusted for sex, age, residential area, education level (≤ 6, 7–9, 10–12, or >12 years), current housing type (building, cottage, or boat), current occupation (unemployed, farmer, blue-collar, white-collar, or other/unknown), first-degree family history of NPC (yes, no, or unknown), tea drinking (less than daily or daily), and salt-preserved fish consumption in 2000–2002 (yearly or less, monthly, or weekly or more). We excluded 7 subjects due to missing covariate values.
Among 2358 participants who experienced tooth loss after age 20 years.