Table 2.
Population based age-specific prevalence differential trends of HIV infection by sex in Chelstone, Lusaka and Kapiri Mposhi, Zambia: 1995–2003
| Sex | Age group (years) | Age-specific Prevalence, % (total number of respondents, n) | |||||||||
| Rural | Urban | ||||||||||
| 1995 | 1999 | 2003 | χ2 for trend (P value) | Age-adjusted ORψ for 2003 (Ref., 1995) | 1995 | 1999 | 2003 | χ2 for trend (P value) | Age-adjusted ORψ for 2003 (Ref., 1995) | ||
| Males | 15–19 | 5.5 (73) | 5.4(129) | 2.1(146) | 0.161 | 4.5(266) | 6.3(224) | 2.2(314) | 0.144 | ||
| 20–24 | 5.8(103) | 9.4(139) | 4.3(163) | 0.468 | 10.7(168) | 8.6(208) | 4.2(309) | 0.006 | |||
| 25–29 | 20.9(67) | 13.2(114) | 12.2(147) | 0.127 | 33.3(114) | 22.0(109) | 13.1(160) | 0.001** | |||
| 30–39 | 31.9(91) | 23.1(169) | 20.8(235) | 0.048 | 40.0(150) | 39.2(120) | 35.4(181) | 0.378 | |||
| 40–49 | 12.3(65) | 12.9(101) | 22.9(131) | 0.036 | 41.5(106) | 40.2(82) | 33.3(78) | 0.276 | |||
| 50–59 | 14.6(48) | 9.3(92) | 17.9(89) | 0.416 | 26.5(34) | 13.5(37) | 25.8(66) | 0.847 | |||
| 15–24 | |||||||||||
| Crude | 5.7(176) | 7.5(268) | 3.2(309) | 0.143 | 0.56(0.25–1.26) | 6.9(434) | 7.4(432) | 3.2(623) | 0.005 | 0.40(0.25–0.66) | |
| Adjusted† | 5.6 | 7.2 | 3.1 | 0.141 | 7.5 | 7.4 | 3.2 | 0.001 | |||
| F:M ratio | 2.8 | 1.46 | 2.06 | 3.12 | 2.47 | 3.87 | |||||
| Urban:Rural ratio | 1.34 | 1.03 | 1.03 | ----- | ----- | ----- | |||||
| 15–49 | |||||||||||
| Crude | 15.3(399) | 13.3(652) | 13.0(822) | 0.314 | 0.80(0.55–1.18) | 21.4(804) | 18.3(743) | 12.6(1042) | 0.000** | 0.58(0.38–0.87) | |
| Adjusted† | 15.4 | 12.8 | 11.6 | 0.072 | 24.8 | 18.3 | 16.9 | 0.000 | |||
| F:M ratio | 1.12 | 1.10 | 1.15 | 1.23 | 1.49 | 1.35 | |||||
| Urban:Rural ratio | 1.61 | 1.43 | 1.46 | ----- | ----- | ----- | |||||
| Females | 15–19 | 8.2(122) | 5.9(217) | 3.1(223) | 0.039 | 12.3(391) | 9.5(336) | 7.7(431) | 0.026 | ||
| 20–24 | 24.6(114) | 15.9(163) | 10.3(233) | 0.001 | 35.4(311) | 27.9(305) | 17.6(409) | 0.000** | |||
| 25–29 | 17.7(79) | 20.6(160) | 18.2(187) | 0.929 | 48.7(199) | 41.2(221) | 31.1(286) | 0.000** | |||
| 30–39 | 19.8(111) | 18.4(233) | 23.8%(256) | 0.249 | 34.5(310) | 39.3(244) | 39.6(273) | 0.202 | |||
| 40–49 | 17.8(73) | 11.7(120) | 14.7(156) | 0.140 | 26.0(100) | 22.3(112) | 22.9(148) | 0.614 | |||
| 50–59 | 15.4(52) | 6.9(110) | 5.3(94) | 0.043 | 0(11) | 25.0(12) | 13.9(36) | 0.444 | |||
| 15–24 | |||||||||||
| Crude | 16.1(236) | 10.3(380) | 6.8(456) | 0.000** | 0.36(0.19–0.67) | 22.5(702) | 18.3(641) | 12.5(840) | 0.000** | 0.43(0.33–0.57) | |
| Adjusted† | 15.7 | 10.5 | 6.4 | 0.000** | 23.4 | 18.3 | 12.4 | 0.000** | |||
| Urban:Rural ratio | 1.49 | 1.74 | 1.94 | ------ | ------ | ------ | |||||
| 15–49 | |||||||||||
| Crude | 17.4(499) | 14.4(893) | 14.1(1055) | 0.118 | 0.76(0.47–1.23) | 29.6(1311) | 27.0(1218) | 21.7(1547) | 0.000** | 0.68(0.57–0.81) | |
| Adjusted† | 17.3 | 14.1 | 13.4 | 0.056 | 30.6 | 27.3 | 22.8 | 0.000** | |||
| Urban:Rural ratio | 1.78 | 1.94 | 1.70 | ||||||||
Notes 1. † Denotes standardised prevalence using the Zambia National Census for the year 2000 as reference population 2. ORψ stands for Odds ratio given with 95%Confidence Interval and adjusted with age as a continuous variable and confidence interval adjusted for clustering effect using Intercooled Stata version 8 with the Standard Enumeration Area (SEA) as clusters. Statistically significant OR, highlighted in bold 3. Chi square for linear trend, Extended Mantel-Haenszel (1 degree of freedom) with continuity correction was used: a) Statistically significant trends are highlighted in bold b) ** denotes P < 0.001 4. Sample sizes were n = 3158 in 1995, 3731 in 1999 & 4751 in 2003 (age group 15–59 years).