Table 1.

Clinical Characteristics of Patients with Nasopharyngeal Carcinoma and Cancer-Free Controls

Characteristics	Cases	Controls	χ2/t	P
n	439	431
Age, yr	46.78±11.43	47.29±13.50	0.597	0.550a
Gender, n			0.153	0.696b
Male	334	323
Female	105	108
EBV-VCA-IgA status, n			372.604	<0.001b
Positive	283	11
Negative	156	420
Smoking history, n			4.397	0.036b
Yes	150	119
No	289	312

Notes: ^aUnpaired, two-tailed Student’s t-test. ^bChi-squared test. Age is presented as average±standard deviation.

Abbreviation: EBV-VCA-IgA, immunoglobin A against Epstein–Barr virus capsid antigen.