Table 3.

Determinants of anal intercourse and condomless anal intercourse over follow-up among women in the Women’s Interagency HIV Study cohort (N = 3,708 over 69,438 visits)

		Any AI				Condomless AI
		Univariate analysis		Multivariable analysis		Univariate analysis		Multivariable analysis
		OR	95% CI	aOR	95% CI	OR	95% CI	aOR	95% CI
HIV status	Seronegative	Ref		Ref		Ref		Ref
	Seropositive	0.67	0.54–0.83	1.04	0.89–1.28	0.45	0.35–0.57	0.61	0.46–0.74
Demographic determinants
Age	Years, continuous	0.94	0.94–0.95	0.97	0.96–0.98	0.94	0.93–0.95	0.96	0.95–0.97
Race and ethnicitya	Non-Hispanic Black	Ref		Ref		Ref		Ref
	Hispanic/Latina	1.50	1.17–1.92	1.88	1.47–2.41	1.45	1.08–1.94	1.65	1.25–2.20
	Non-Hispanic White	1.40	0.98–1.99	1.62	1.15–2.30	0.98	0.63–1.39	1.05	0.73–1.55
	Other	1.21	0.71–2.03	1.29	0.79–2.03	1.23	0.66–2.30	1.21	0.82–2.18
Educationa	< High school	Ref		Ref		Ref		Ref
	≥ High school	1.20	0.98–1.48	1.33	1.08–1.65	1.09	0.85–1.40	1.25	0.97–1.61
Married or living with a partner	No	Ref		Ref		Ref		Ref
	Yes	1.12	0.94–1.33	0.88	0.76–1.06	1.24	1.03–1.51	1.10	0.93–1.32
Household annual income	< $12,000	Ref		Ref		Ref		Ref
	≥ $12,000	1.19	1.02–1.39	1.14	0.98–1.33	1.06	0.86–1.26	0.98	0.81–1.15
Violence victimization	None	Ref		Ref		Ref		Ref
	Either physical or sexual	2.64	2.18–3.18	1.35	1.10–1.62	2.94	2.35–3.56	1.62	1.28–2.08
	Both physical and sexual	4.50	2.95–7.12	1.77	1.13–2.82	5.82	3.37–9.06	2.50	1.44–4.12
Behavioral determinants
Alcohol use	< 8 drinks/week	Ref		Ref		Ref		Ref
	≥ 8 drinks/week	1.91	1.55–2.31	1.27	1.05–1.51	1.96	1.56–2.34	1.31	1.04–1.62
Crack, cocaine or heroin use	No	Ref		Ref		Ref		Ref
	Yes	2.08	1.69–2.52	1.34	1.09–1.66	2.05	1.61–2.62	1.35	1.02–1.78
Number of male sex partners and exchange sexb	1 partner, no exchange sex	Ref		Ref		Ref		Ref
	≥ 2 partners, no exchange sex	2.64	2.23–3.11	2.10	1.79–2.50	2.49	2.00–3.03	1.91	1.52–2.33
	Any exchange sex	3.45	2.53–4.71	2.20	1.57–3.13	3.21	2.13–4.68	1.83	1.16–2.81
Number of female sex partners	0	Ref		Ref		Ref		Ref
	≥ 1	1.11	0.84–1.47	1.32	1.01–1.75	1.21	0.87–1.71	1.32	0.89–1.92
Condomless VI	No	Ref		Ref		–	–	–	–
	Yes	3.48	2.95–4.02	1.80	1.53–2.09	–	–	–	–
Psycho-social determinants
High depressive symptomsc	No	Ref		Ref		Ref		Ref
	Yes	1.36	1.19–1.53	1.23	1.08–1.39	1.42	1.20–1.67	1.25	1.03–1.48

Visits for which AI data were available and for which the prior visit was no longer than 12 months ago (i.e., maximum one visit skipped) were included in the analysis. Most follow-up visits (93.1%) were six months apart, with 5.3% of visits occurring after one skipped visit; applying this criterion therefore removed only 1.6% of visits. Missing values for covariates were imputed (see Methods for details). The covariates HIV status, age and race and ethnicity had no missing values. Education status was missing for 1 woman (measured at baseline). Data on marital status were missing at 4.9% of visits, household income at 5.7%, violence victimization at 39.2%, alcohol use at 3.6%, crack, cocaine, or heroin use at 3.5%, number of male partners and exchange sex at 6.0%, number of female partners at 3.5%, condomless VI at 5.2% and high depressive symptoms at 11.3% of visits

OR odds ratio, aOR adjusted odds ratio, CI confidence interval, VI vaginal intercourse. All covariates were collected over follow-up and represent since the last visit except race and ethnicity and education level, which were measured at baseline. Results in bold indicate that the 95% CI does not include the null value

^aVariables measured at baseline. All other variables were measured over follow-up. ^bWomen reported only one male sex partner at 197 of 1487 visits (13.2%) where exchange sex was reported. ^cScores of > 15 in the Center for Epidemiologic Studies Depression Scale were defined as high depressive symptoms(36)