Table 2.
Associations Between Potential Risk Factors and Oral Epstein-Barr Virus (EBV) Levels Among Healthy Subjects in China
| Variablea | Subjects With Low Oral EBV Loads,b No. (%) |
Subjects With High Oral EBV Loads,b No. (%) |
OR (95% CI) | Adjusted OR (95% CI)c |
|---|---|---|---|---|
| Age, y | ||||
| ≤30 | 270 (57.20) | 202 (42.80) | 1.00 (reference) | 1.00 (reference) |
| 31–40 | 865 (52.78) | 774 (47.22) | 1.20 (.97–1.47) | 1.14 (.92–1.40) |
| 41–50 | 1106 (51.78) | 1030 (48.22) | 1.24 (1.02–1.52) | 1.15 (.93–1.41) |
| 51–60 | 715 (45.22) | 866 (54.78) | 1.62 (1.32–1.99) | 1.48 (1.19–1.83) |
| >60 | 321 (44.03) | 408 (55.97) | 1.70 (1.34–2.15) | 1.60 (1.26–2.04) |
| P trend d | <.001 | <.001 | ||
| Sex | ||||
| Female | 1102 (63.04) | 646 (36.96) | 1.00 (reference) | 1.00 (reference) |
| Male | 2175 (45.22) | 2635 (54.78) | 2.07 (1.85–2.31) | 2.05 (1.83–2.30) |
| Education level | ||||
| High school or less | 2284 (48.31) | 2444 (51.69) | 1.00 (reference) | 1.00 (reference) |
| University or greater | 968 (54.05) | 823 (45.95) | 0.79 (.71–.89) | 0.88 (.78–.98) |
| Family history of tumor | ||||
| No | 2713 (50.30) | 2681 (49.70) | 1.00 (reference) | 1.00 (reference) |
| Yes | 529 (48.27) | 567 (51.73) | 1.08 (.95–1.24) | 1.06 (.92–1.21) |
| Family history of NPC | ||||
| No | 3186 (49.97) | 3190 (50.03) | 1.00 (reference) | 1.00 (reference) |
| Yes | 56 (49.12) | 58 (50.88) | 1.03 (.71–1.50) | 1.11 (.76–1.61) |
| Cigarette smoking | ||||
| Never smoker | 1930 (57.46) | 1429 (42.54) | 1.00 (reference) | 1.00 (reference) |
| Former smoker | 314 (50.48) | 308 (49.52) | 1.32 (1.11–1.57) | 0.97 (.80–1.17) |
| Current smoker | 1026 (40.05) | 1536 (59.95) | 2.02 (1.82–2.24) | 1.58 (1.39–1.79) |
| P trend d | <.001 | <.001 | ||
| Alcohol consumption | ||||
| Nondrinker | 1493 (45.98) | 1754 (54.02) | 1.00 (reference) | 1.00 (reference) |
| ≤1 drink/day | 688 (51.08) | 659 (48.92) | 0.82 (.72–.93) | 0.74 (.65–.85) |
| ＞1 drink/day | 694 (47.86) | 756 (52.14) | 0.93 (.82–1.05) | 0.80 (.70–.91) |
| P trend d | .083 | <.001 | ||
| Preserved vegetable consumption | ||||
| Less than monthly | 2276 (47.52) | 2514 (52.48) | 1.00 (reference) | 1.00 (reference) |
| Monthly | 399 (45.39) | 480 (54.61) | 1.09 (.94–1.26) | 1.14 (.98–1.32) |
| Weekly or more | 190 (51.77) | 177 (48.23) | 0.84 (.68–1.04) | 0.83 (.67–1.03) |
| P trend d | .540 | .696 | ||
| Tea intake | ||||
| Less than monthly | 390 (41.01) | 561 (58.99) | 1.00 (reference) | 1.00 (reference) |
| Monthly | 309 (45.71) | 367 (54.29) | 0.83 (.68–1.01) | 0.81 (.66–1.00) |
| Weekly or more | 508 (41.20) | 725 (58.80) | 0.99 (.84–1.18) | 0.77 (.64–.93) |
| P trend d | .965 | .008 | ||
| Herbal tea intake | ||||
| Less than monthly | 262 (45.09) | 319 (54.91) | 1.00 (reference) | 1.00 (reference) |
| Monthly | 562 (39.63) | 856 (60.37) | 1.25 (1.03–1.52) | 1.26 (1.03–1.55) |
| Weekly or more | 376 (44.44) | 470 (55.56) | 1.03 (.83–1.27) | 1.00 (.81–1.25) |
| P trend d | .904 | .695 | ||
| Cantonese soup consumption | ||||
| Less than monthly | 50 (45.05) | 61 (54.95) | 1.00 (reference) | 1.00 (reference) |
| Monthly | 192 (36.02) | 341 (63.98) | 1.46 (.96–2.20) | 1.56 (1.02–2.38) |
| Weekly or more | 958 (43.57) | 1241 (56.43) | 1.06 (.72–1.56) | 1.15 (.78–1.70) |
| P trend d | .053 | .119 | ||
| Salted fish consumption | ||||
| Less than monthly | 1122 (42.27) | 1519 (57.73) | 1.00 (reference) | 1.00 (reference) |
| Monthly | 44 (35.48) | 80 (64.52) | 1.33 (.91–1.94) | 1.30 (.89–1.90) |
| Weekly or more | 45 (47.37) | 50 (52.63) | 0.81 (.54–1.23) | 0.80 (.52–1.22) |
| P trend d | .875 | .779 | ||
aData on Cantonese tea, Chinese herbal tea, slow-cooked soup, and salted fish were available only for the 21RCCP and south populations.
bOral EBV levels were divided into low and high levels according to the median number of EBV copies in saliva or mouthwash per milliliter. For mouthwash EBV loads in the 21RCCP population, a low EBV level refers to <104.55 copies/mL of mouthwash and a high EBV level refers to ≥104.55 copies/mL of mouthwash; for salivary EBV loads in the south, north, and northeast populations, a low EBV level refers to <104.47 copies/mL of saliva, and a high EBV level refers to ≥104.47 copies/mL of saliva.
cMultivariable logistic regression was used by adjusting for age (continuous variable), sex (male or female), and education level (high school and less or university and greater).
dLinear trends tests were performed by treating ordered categorical variables as continuous variables.