Associations between sexual behaviour change in young people and decline in HIV prevalence in Zambia

BMC Public Health

Table 5 Age-adjusted odds ratio (AOR) of risk of HIV by survey time comparing 2003 and 1995, adjusting for sexual behaviour variables, for urban women aged 15–24

One by one behaviour indicator included				Two behaviour variables included				Three behaviour variables included
Beh. indicator	Chi-square change	AOR	95% CI	Beh. indicator	Chi-square change	AOR	95% CI	Beh. indicator	Chi-square change	AOR	95% CI
Ever given birth	-4.51	0.49	0.37–0.63	Casual partner and ever given birth**	-8.34	0.59	0.42–0.83	-
Number of sex partners past 12 months	-26.97	0.52	0.38–0.70	Casual partner and number of sex partners	-1.38	0.53	0.38–0.73	Casual partner, ever given birth and number of sexual partners	1.62	0.58	0.41–0.82
Casual partner past year**	-27.25	0.54	0.39–0.75	-				-
Condom use at last sexual intercourse	6.57	0.45	0.32–0.63	Casual partner and condom use at last sexual intercourse	13.53	0.46	0.34–0.63	Casual partner, ever given birth and condom use at last sexual intercourse*	16.44	0.52	0.37–0.72
Ever used condom	-18.06	0.50	0.37–0.68	Casual partner and ever used condom	3.37	0.51	0.37–0.68	Casual partner, ever given birth and ever used condom*	4.32	0.56	0.41–0.76
Frequent dry sex	-30.29	0.49	0.37–0.64	Casual partner and frequent dry sex	-8.85	0.54	0.38–0.77	Casual partner, ever given birth and frequent dry sex#	-5.83	0.59	0.42–0.83

Notes: Before adding the behaviour variables the Chi square was 53.88 and AOR 0.35 (0.28–0.45) in 2003 compared to 1995. If the chi square changed > |3.84|, the added variable was a confounding variable. The denominator was the number of sexually active respondents during the year prior to the survey.
*The Chi square change was significant, but the AOR was further from 1, which meant that adjusting for 'condom use at last sexual intercourse' or 'ever condom use' in addition to 'any casual partners past year' increased the strength of the association between HIV and survey time, rather than reducing it. # The Chi square change was significant, but the AOR was unchanged. **The chief confounder in this step.

ISSN: 1471-2458