Table 4.

Logistic regression model^* to identify determinants of hepatitis C antibodies in non-users of injected drugs entering Irish prisons

	Total No of prisoners (n=420)†	No (%) of prisoners positive for antibodies	Odds ratio (95% CI)	P value‡
Hepatitis C antibodies (n=4)
Tattooed outside prison	167	1 (0.6)	1
Tattooed inside prison	46	3 (6.5)	11.6 (1.4 to 237.3)	0.04
No tattoo	205	0

^*Initial model included the variables age, sex, ever imprisoned, time spent in prison in past 10 years, tattooing, smoking heroin, ever had sex with a man inside or outside prison, ever treated for a sexually transmitted infection, number of heterosexual partners, use of condoms during heterosexual intercourse, and ever been paid for sex. Significant factors were retained in the final model. 

^†Numbers may not add up to total because not all respondents answered all questions. 

^‡For whole model for hepatitis C, χ²=5.3, P=0.02.