Table 3.
Incidence of and Adjusted Hazard Ratios for Nasopharyngeal Carcinoma, by Combination of Anti-Epstein-Barr Virus Seromarkers, Family History, and Cumulative Cigarette Smoking at Study Entry, Taiwan, 1984–2008
| Variable |
No. of Participants | Person-Years | No. of Cases | Cumulative Incidencea | Hazard Ratiob | 95% Confidence Interval | P for Interaction | |
| Combination of VCA IgA and deoxyribonuclease | Family historyc | 0.533 | ||||||
| Both negative | No | 8,357 | 1,62,372.5 | 22 | 13.5 | 1.0 | Referent | |
| Both negative | Yes | 523 | 4,718.0 | 2 | 42.4 | 5.5 | 1.1, 26.8 | |
| Any positive | No | 1,210 | 22,104.7 | 10 | 45.2 | 3.1 | 1.4, 6.9 | |
| Any positive | Yes | 233 | 2,082.5 | 5 | 240.1 | 31.0 | 9.7, 98.7 | |
| Cumulative cigarette smoking, pack-years | Family historyd | 0.310 | ||||||
| <30 | No | 7,199 | 1,44,173.4 | 18 | 12.5 | 1.0 | Referent | |
| <30 | Yes | 884 | 7,072.4 | 9 | 127.3 | 14.5 | 5.1, 41.2 | |
| ≥30 | No | 2,074 | 35,101.5 | 13 | 37.0 | 2.7 | 1.2, 6.0 | |
| ≥30 | Yes | 134 | 983.8 | 1 | 101.6 | 12.4 | 1.5, 102.8 | |
| Combination of VCA IgA and deoxyribonuclease | Cumulative cigarette smoking, pack-yearse | 0.862 | ||||||
| Both negative | <30 | 6,777 | 1,31,514.3 | 16 | 12.2 | 1.0 | Referent | |
| Both negative | ≥30 | 1,810 | 30,268.1 | 7 | 23.1 | 1.9 | 0.7, 5.1 | |
| Any positive | <30 | 1,038 | 17,771.0 | 9 | 50.6 | 4.2 | 1.9, 9.6 | |
| Any positive | ≥30 | 352 | 5,474.3 | 5 | 91.3 | 6.9 | 2.1, 21.9 | |
Abbreviations: IgA, immunoglobulin A; VCA, viral capsid antigen.
Per 100,000 person-years.
Adjusted for age (continuous), ethnicity (Fukkinese or non-Fukkinese), and years of schooling (0–6 years or ≥7 years).
Data for the combination of anti-Epstein-Barr virus seromarkers and family history were not available for 318 participants, including 4 nasopharyngeal carcinoma cases.
Data for the combination of cumulative cigarette smoking and family history were not available for 350 participants, including 2 nasopharyngeal carcinoma cases.
Data for the combination of anti-Epstein-Barr virus seromarkers and cumulative cigarette smoking were not available for 664 participants, including 6 nasopharyngeal carcinoma case.