Genetic factors leading to chronic Epstein-Barr virus infection and nasopharyngeal carcinoma in South East China: Study design, methods and feasibility

Table 3 Phase II study design and non-genetic covariates.

Exposure	EBV/IgA/VCA status
	NPC/IgA+	IgA⁺	IgA^-
No. enrolled¹	1024	1009	1022
Male: female(% male)	735/289(72%)	555/454(55%)	684/338(67%)
Consume dried meat²	292 (28.5%)	172 (17.0%)	283 (27.7%)
Wood cooking fires²	995 (97.2%)	960 (95.1%)	914 (89.4%)
Occupational exposure to solvents²	78 (07.6%)	31 (03.1%)	87 (08.5%)
Smoking > 10 years	531 (51.9%)	408 (40.4%)	372 (36.4%)

Abbreviations: EBV, Epstein-Barr virus; IgA, immunoglobulin A; NPC, nasopharyngeal carcinoma; VCA, viral capsid antigens.
¹ Greater than 99 per cent of IgA⁺ and IgA^- participants and 100 per cent of the NPC cases were born in Guangdong or Guangzhou provinces.
² Participants reporting any level exposure.

ISSN: 1479-7364