Table 5.

Logistic Regression Models of Factors Associated with Being a Female Sex Worker Versus a Single Mother Among HIV− Women at Baseline in Lusaka and Ndola, Zambia (n = 942)

	Bivariate models				Final multivariate model
	95% CI				95% CI
	cOR	LLa	ULb	p	aOR	LLa	ULb	p
Age (per 1 year increase)	1.05	1.03	1.08	<.0001	1.13	1.09	1.18	<.0001
Age at first sexual encounter (per 1 year increase)	0.84	0.80	0.89	<.0001	0.84	0.77	0.91	<.0001
Marital status
Single	1.89	1.40	2.57	<.0001	3.90	2.32	6.58	<.0001
Divorced/separated/widowed	Ref	—	—	—	Ref	—	—	—
Reads vernacular language (Bemba or Nyanja) x city
Easily (for either language) versus with difficulty/not at all (for both languages) in Ndola	2.36	1.70	3.26	<.0001	2.07	1.25	3.42	.0045
Easily versus with difficulty/not at all in Lusaka	0.85	0.55	1.33	.4850	0.72	0.37	1.38	.3205
Highest education level completed x city
Primary versus none in Ndola	1.40	0.79	2.46	.2458	1.77	0.76	4.16	.1876
Primary versus none in Lusaka	0.19	0.05	0.72	.0139	0.13	0.03	0.67	.0147
Secondary/college versus none in Ndola	2.22	1.22	4.05	.0091	4.11	1.59	10.62	.0035
Secondary/college versus none in Lusaka	0.17	0.05	0.59	.0058	0.10	0.02	0.52	.0059
Pressure or force at first sexual intercourse x city
Pressured verbally versus willingly in Ndola	0.81	0.50	1.30	.3797	1.06	0.53	2.14	.8686
Pressured verbally versus willingly in Lusaka	0.81	0.46	1.46	.4871	0.49	0.22	1.11	.0866
Forced physically versus willingly in Ndola	2.67	1.60	4.48	.0002	4.41	2.05	9.48	.0001
Forced physically versus willingly in Lusaka	1.06	0.55	2.03	.8693	0.97	0.39	2.42	.9454
Received money/goods/favors at first sexual intercourse
No	Ref	—	—	—	Ref	—	—	—
Yes	6.54	4.91	8.70	<.0001	6.21	4.16	9.28	<.0001
Ever uses alcohol
No	Ref	—	—	—	Ref	—	—	—
Yes	16.14	11.69	22.30	<.0001	13.47	9.05	20.05	<.0001

The following variable was not significant in bivariate analyses and is not tabled: years living in Lusaka/Ndola (continuous). The following variables and interaction terms were not significant in initial adjusted analyses and were removed from the final multivariate model through backward elimination and are not tabled: interaction terms between city and marital status and city and current contraceptive method, and current contraceptive method.

^aLower limit for 95% CI.

^bUpper limit for 95% CI.