Table III.
Demographic and exposure variables by methylation status
| Cases (N = 99) |
Controls (N = 99) |
|||||
| Methylated, n = 21 | Unmethylated, n = 78 | P-value | Methylated, n = 3 | Unmethylated, n = 96 | P-value | |
| Age, mean years (median) | 64.7 (61.7) | 58.6 (57.9) | 0.02a | 54.9 (53.8) | 57.7 (57.2) | 0.51b |
| Gender, n (%) | 0.10c | >0.99c | ||||
| Female | 9 (42.9%) | 18 (23.1%) | 1 (33.3%) | 26 (27.1%) | ||
| Male | 12 (57.1%) | 60 (76.9%) | 2 (66.7%) | 70 (72.9%) | ||
| Daily servings of fruits and vegetables, mean (median) | 1.5 (1.1) | 1.8 (1.3) | 0.51b | 2.9 (2.7) | 2.9 (3.0) | 0.80b |
| BMI (kg/m2)d, mean (median) | 23.9 (23.0) | 28.0 (27.2) | 0.002b | 28.7 (29.0) | 28.4 (27.4) | 0.83b |
| Cigarette use | 0.14c | 0.57c | ||||
| Never | 2 (9.5%) | 21 (26.9%) | 1 (33.3%) | 56 (58.3%) | ||
| Ever | 19 (90.5%) | 57 (73.1%) | 2 (66.7%) | 40 (41.7%) | ||
| Years smoking, mean (median) | 42.0 (41.0) | 33.6 (35.0) | 0.01a | 26.5 (26.5) | 25.5 (26.0) | 0.95b |
| Packs/day, mean (median) | 1.1 (1.0) | 1.3 (1.0) | 0.36b | 0.8 (0.8) | 1.2 (1.0) | 0.53b |
| Age started smoking, mean (median) | 19.7 (17.0) | 17.1 (17.0) | 0.51b | 16.5 (16.5) | 16.4 (17.5) | 0.68b |
| Alcohol use | 0.58c | >0.99c | ||||
| Never | 4 (19.1%) | 21 (26.9%) | 1 (33.3%) | 26 (27.1%) | ||
| Ever | 17 (81.0%) | 57 (73.1%) | 2 (66.7%) | 70 (72.9%) | ||
| Years drinking, mean (median) | 39.4 (38.0) | 32.6 (33.0) | 0.05a | 27.0 (27.0) | 25.9 (28.0) | 0.95b |
| Drinks/day, mean (median) | 2.4 (2.0) | 3.1 (1.7) | 0.64b | 2.9 (2.9) | 1.3 (0.3) | 0.19b |
| Age started drinking, mean (median) | 22.6 (21.0) | 20.2 (18.0) | 0.18b | 17.5 (17.5) | 23.4 (21.0) | 0.12b |
| Combined tobacco/alcohol use | 0.64c | 0.57c | ||||
| Never/never | 0 (0.0%) | 7 (9.0%) | 0 (0.0%) | 17 (17.7%) | ||
| Never/ever | 2 (9.5%) | 9 (11.5%) | 1 (33.3%) | 34 (35.4%) | ||
| Ever/never | 4 (19.1%) | 14 (18.0%) | 1 (33.3%) | 9 (9.4%) | ||
| Ever/ever | 15 (71.4%) | 48 (61.5%) | 1 (33.3%) | 36 (37.5%) | ||
| Wear dentures, n (%) | 0.01c | 0.48c | ||||
| No | 6 (28.6%) | 47 (60.3%) | 2 (66.7%) | 78 (81.3%) | ||
| Yes | 15 (71.4%) | 31 (39.7%) | 1 (33.3%) | 18 (18.8%) | ||
| Years wearing dentures, mean (median) | 26.1 (22.0) | 26.8 (25.0) | 0.93b | 47.0 (47.0) | 18.3 (11.5) | 0.12b |
| Mouthwash use, n (%) | >0.99c | >0.99c | ||||
| No | 7 (33.3%) | 28 (35.9%) | 1 (33.3%) | 42 (43.8%) | ||
| Yes | 14 (66.7%) | 50 (64.1%) | 2 (66.7%) | 54 (56.3%) | ||
| Times per week, mean (median) | 7.7 (7.0) | 7.4 (7.0) | 0.86b | 10.5 (10.5) | 7.0 (7.0) | 0.21b |
| Years of regular mouthwash use, mean (median) | 26.4 (30.0) | 19.2 (20.0) | 0.06a | 21.0 (21.0) | 15.5 (10.0) | 0.89b |
| Tumor site, n (%) | 0.009c | |||||
| Oral cavity | 14 (66.7%) | 23 (29.5%) | — | — | ||
| Pharynx | 5 (23.8%) | 32 (41.0%) | — | — | ||
| Larynx | 2 (9.5%) | 23 (29.5%) | — | — | ||
| Stage at diagnosis, n (%) | >0.99c | |||||
| Local (stages I and II) | 7 (33.3%) | 25 (33.3%) | — | — | ||
| Advanced (stages III and IV) | 14 (66.7%) | 50 (66.7%) | — | — | ||
| Tumor grade, n (%) | 0.51c | |||||
| Well differentiated | 0 (0.0%) | 6 (9.4%) | — | — | ||
| Moderately differentiated | 16 (80.0%) | 44 (68.8%) | — | — | ||
| Poorly differentiated | 4 (20.0%) | 14 (21.9%) | — | — | ||
a
Two-sample t-test.
b
Mann-Whitney U-test.
c
Fisher's exact test.
d
Estimated for 1 year prior to study enrollment based on patient reported weight at that time.