Table 5.
Multivariate prevalence ratiosa (CI95%) for Chlamydia and HSV-2 infectionb
| Variable | Categories | PR of Chlamydia | PR of HSV-2 |
| Age | 15 – 18 | 1.0 | 1.0 |
| 19 – 21 | 0.892 (0.524 – 1.307) | 2.023 (1.167 – 2.940)*** | |
| Years of sexual activity | < 1 year | 1.0 | 1.0 |
| 2 to 3 | 1.096 (0.856 – 1.259) | 1.133 (0.766 – 1.397) | |
| 4 or more | 1.202 (0.675 – 1.566) | 0.994 (0.594 – 1.349) | |
| Sex | Women | 1.0 | 1.0 |
| Men | 0.533 (0.239 – 0.881)*** | 0.446 (0.221 – 0.765)*** | |
| Socioeconomic level | Lowest 20% | 1.0 | 1.0 |
| Second lower 20% | 0.991 (0.823 – 1.086) | 0.885 (0.685 – 1.001)* | |
| Remaining 60% | 1.090 (0.884 – 1.148) | 1.009 (0.848 – 1.087) | |
| Adolescent attends school | No | 1.0 | 1.0 |
| Yes | 1.036 (0.742 – 1.123) | 0.995 (0.712 – 1.048) | |
| Education level appropriate for age | No | 1.0 | 1.0 |
| Yes | 0.861 (0.393 – 1.029) | 0.989 (0.770 – 1.012) | |
|
Educational gap for adolescents not attending school and for those with education level not age appropriate |
No gap | 1.0 | 1.0 |
| Years of gap | 0.996 (0.985 – 1.007) | 0.992 (0.978 – 1.003) | |
| Participates in labor force | No | 1.0 | 1.0 |
| Yes | 0.919 (0.598 – 1.161) | 1.120 (0.813 – 1.372) | |
| Attends school and participates in labor force | No | 1.0 | 1.0 |
| Yes | 1.005 (0.895 – 1.018) | 0.968 (0.602 – 0.999)*** | |
| Lives with a partner | No | 1.0 | 1.0 |
| Yes | 0.760 (0.362 – 1.189) | 0.989 (0.597 – 1.394) | |
| Has close friend they can count on | No | 1.0 | 1.0 |
| Yes | 0.721 (0.328 – 1.337) | 0.990 (0.458 – 1.854) | |
| Drinks alcohol | No | 1.0 | 1.0 |
| Yes | 1.099 (0.848 – 1.240) | 1.042 (0.693 – 1.241) | |
| Smokes | No | 1.0 | 1.0 |
| Yes | 1.174 (1.034 – 1.226)** | 1.173 (0.979 – 1.251)* | |
| Reported STI symptoms | No | 1.0 | 1.0 |
| Yes | 0.969 (0.656 – 1.004) | 1.023 (0.968 – 1.030) | |
| Used condom in last sex | No | 1.0 | 1.0 |
| Yes | 1.151 (0.916 – 1.269) | 1.113 (0.870 – 1.232) | |
| Reported compensated sex | No | 1.0 | 1.0 |
| Yes | 1.014 (1.006 – 1.015)** | 1.049 (0.012 – 1.052)** | |
| Geographical area of residence | Center | 1.0 | 1.0 |
| Gulf | 1.274 (0.984 – 1.436)* | 1.710 (1.291 – 1.906)*** | |
| North | 1.217 (0.744 – 1.391) | 0.911 (0.462 – 0.999)* | |
| Pacific, North | 0.944 (0.505 – 1.035) | 1.040 (0.968 – 1.058) | |
| Pacific, Central | 0.954 (0.723 – 1.037) | 1.093 (0.995 – 1.128)* | |
| Pacific, South | 1.019 (0.817 – 1.080) | 1.151 (1.023 – 1.190)** | |
| Yucatan peninsula | 0.976 (0.792 – 0.998)*** | 1.005 (0.915 – 1.014) | |
| Nc | 1177 | 713 |
a Estimated using the formulae PR = OR/ [(1-P0)+(P0*OR)] as suggested by Zhang & Yu [18]. b Confidence intervals were estimated reflecting design effect. c Number of observations is less than in descriptive because of missing values. ***P-value < 1%; **P-value < 5%; * P-value < 10%