Table 1.
Baseline characteristics, crude and age-adjusted incidence rates (1/100,000 person-years) of nasopharyngeal carcinoma (NPC) among 18,411 participants in the Sihui NPC screening cohort, Sihui, Guangdong, China (1987–2007).
Figure 1.
Cumulative probability of developing nasopharyngeal carcinoma (NPC) during follow-up among 18,411 subjects, according to baseline levels of IgA antibodies against EBV capsid antigen (VCA/IgA) (1987–2007).
Table 2.
Hazard ratios (HRs) and 95% confidence intervals (CIs) for nasopharyngeal carcinoma associated with baseline or repeated levels of antibodies against Epstein-Barr virus antigens.
Figure 2.
Variation of IgA antibodies against Epstein-Barr virus capsid (VCA/IgA) or early antigen (EA/IgA) over time in 42 subjects who developed nasopharyngeal carcinoma (NPC) during follow-up and in 1,276 subjects who were NPC-free by the end of follow-up, among the group baseline seropositive for VCA/IgA (1,318 subjects).
Note: Geometric means of serolgocial titres in each follow-up year were calculated. Specifically, the numbers of tests were 42, 37, 18, 19, 5, 16 and 11 for baseline, 1st year, 2nd year, 3rd year, 4th year, 5th year and 6th or more year of follow-up, respectively in NPC group. The numbers of tests were 1276, 1217, 615, 813, 287, 1008 and 708 for baseline, 1st year, 2nd year, 3rd year, 4th year, 5th year and 6th or more year of follow-up, respectively in NPC-free group.
Table 3.
Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for nasopharyngeal carcinoma (NPC) by fluctuant type of serological status during follow-up among 962 subjects seropositive for VCA/IgA antibodies against EBV capsid antigen compared to 17,093 seronegative subjects at baseline*.
Figure 3.
Time-dependent ROC curve analysis for nasopharyngeal carcinoma (NPC) prediction according to baseline levels of IgA antibodies against EBV capsid antigen (VCA/IgA) and early antigen (EA/IgA) (ordinal categorical variable).
ROC, receiver operating characteristic; AUC, area under the ROC curve, NPC, nasopharyngeal carcinoma.
Figure 4.
Protocol of Serological Tests for Anti-Epstein-Barr Virus Antibodies in the Nasopharyngeal Carcinoma Screening Cohort from 1987 to 2007 in Sihui, Guangdong, China.
Figure 5.
Graph of displaying different fluctuation patterns in 962 subjects seropositive for baseline VCA-IgA test and with at least 2 repeated tests during the first 5 years of follow-up.
The red arrow shows that titers of VCA/IgA were higher than those in the previous test. The blue arrow shows that titers of VCA/IgA were equal to those in the previoust test. The green arrow shows that titers of VCA/IgA were lower than those in the previous test. Therefore, according to the definition, 129 (21+70+38) subjects were classified into the Ascending group, 407 (72+279+56) into the Descending group and 426 (178+26+222) into the Stable group. VCA/IgA, IgA antibodies against EBV capsid antigen; EA/IgA, IgA antibodies against EBV early antigen. Definition: Ascending group: Subjects whose repeated antibody titres were equal or higher than those in the previous test and the titres in the 3rd test were higher than the baseline. Descending group: Subjects whose repeated antibody titres were equal or lower than those in the previous test and the titres in the 3rd test were lower than the baseline. Stable group: The rest of subjects.