Table 2. Summary of the association between a measure of anti-HPV-16 antibody titre and the risk of conjunctival neoplasia.

	HIV seronegative	HIV seropositive	All subjects
Anti-HPV-16 antibody status	Odds ratio and 95% confidence intervalsa	Odds ratio and 95% confidence intervalsa	Odds ratio and 95% confidence intervalsb
Seronegative	1.0	1.0	1.0
Seropositive–low titre	0.5 (0.1–1.9)	1.2 (0.1–10.7)	0.6 (0.2–2.0)
Seropositive–high titre	2.2 (0.2–20.8)	—	3.3 (0.4–27.6)
	χ2 trend (1 d.f.)=0.0	χ2 trend (1 d.f.)=0.8	χ2 trend (1 d.f.)=0.4
	P=0.9	P=0.4	P=0.5

^aOdds ratios adjusted for age group (<25, 25–34, 34+years) and sex.

^bOdds ratios adjusted for age group, sex and HIV serostatus. d.f.=degrees of freedom.