Table 1.
Distribution of non-genetic variables in cases and controls
| Variable | Cases (n=1227) | Controls (n=1325) | Chi-square or t- test, unadjusted p-value |
|||
|---|---|---|---|---|---|---|
| na | (col %) | na | (col %) | |||
| Age (years) | ||||||
| 20–49 | 239 | 19.5% | 151 | 11.4% | <0.0001 | |
| 50–54 | 189 | 15.4% | 156 | 11.8% | ||
| 55–59 | 207 | 16.9% | 199 | 15.0% | ||
| 60–64 | 205 | 16.7% | 202 | 15.2% | ||
| 65–69 | 168 | 13.7% | 237 | 17.9% | ||
| 70–74 | 135 | 11.0% | 216 | 16.3% | ||
| 75–80 | 84 | 6.8% | 164 | 12.4% | ||
| Sex | ||||||
| Male | 938 | 76.4% | 924 | 69.7% | 0.0001 | |
| Female | 289 | 23.6% | 401 | 30.3% | ||
| Race | ||||||
| European-American | 922 | 75.1% | 1074 | 81.1% | 0.0003 | |
| African-American | 305 | 24.9% | 251 | 18.9% | ||
| Drinking (lifetime ethanol intake in ml) | <0.0001 | |||||
| never drinkers | 117 | 9.5% | 280 | 21.1% | ||
| >0 to <134,699 | 210 | 17.1% | 467 | 35.2% | ||
| 134,699 to 757,550 | 318 | 25.9% | 360 | 27.2% | ||
| 757,550+ | 505 | 41.2% | 173 | 13.1% | ||
| missing | 77 | 6.3% | 45 | 3.4% | ||
| Smoking (duration in years) | <0.0001 | |||||
| 0 | 160 | 13.0% | 497 | 37.5% | ||
| 1–19 | 104 | 8.5% | 266 | 20.1% | ||
| 20–39 | 435 | 35.5% | 314 | 23.7% | ||
| 40–49 | 295 | 24.0% | 131 | 9.9% | ||
| 50+ | 155 | 12.6% | 71 | 5.4% | ||
| Missing | 78 | 6.4% | 46 | 3.5% | ||
| Poverty group (at or above, or below, federal poverty guideline) | <0.0001 | |||||
| >= poverty guideline | 816 | 66.5% | 1088 | 82.1% | ||
| <poverty guideline | 356 | 29.0% | 187 | 14.1% | ||
| Had a routine dental visit in past 10 years? | <0.0001 | |||||
| Yes | 781 | 63.7% | 1115 | 84.2% | ||
| No | 438 | 35.7% | 210 | 15.8% | ||
| Drank alcoholic beverages in prior 20 years? | 0.8851 | |||||
| No | 24 | 2.0% | 27 | 2.0% | ||
| Yes | 1202 | 98.0% | 1298 | 98.0% | ||
| Ever exposed to environmental tobacco smoke at work | 0.0024 | |||||
| No | 316 | 25.8% | 414 | 31.2% | ||
| Yes | 909 | 74.1% | 911 | 68.8% | ||
| Ever exposed to environmental tobacco smoke at home | <0.0001 | |||||
| No | 399 | 32.5% | 592 | 44.7% | ||
| Yes | 827 | 67.4% | 732 | 55.2% | ||
| Ever used non-cigarette tobacco products | 0.1165 | |||||
| No | 754 | 61.5% | 854 | 64.5% | ||
| Yes | 473 | 38.5% | 471 | 35.5% | ||
| Had health insurance at reference date | <0.0001 | |||||
| Yes | 1068 | 87.0% | 1250 | 94.3% | ||
| No | 154 | 12.6% | 74 | 5.6% | ||
| Highest education level attained | <0.0001 | |||||
| >=high school | 828 | 67.5% | 1123 | 84.8% | ||
| <high school | 399 | 32.5% | 202 | 15.2% | ||
| Ever had loose permanent tooth due to disease | <0.0001 | |||||
| No | 765 | 62.3% | 1018 | 76.8% | ||
| Yes | 455 | 37.1% | 305 | 23.0% | ||
| Ever regularly used mouthwash | 0.8572 | |||||
| No | 502 | 40.9% | 549 | 41.4% | ||
| Yes | 719 | 58.6% | 775 | 58.5% | ||
| Family history of SCCHN among 1st degree relatives | 0.3848 | |||||
| No | 1206 | 98.3% | 1296 | 97.8% | ||
| Yes | 21 | 1.7% | 29 | 2.2% | ||
| Mean % African ancestry | 0.0008 | |||||
| 23.8% | 19.7% | |||||
a
Frequencies for all variables may not sum to the total number of cases and controls, due to missing values