Abstract
Objective
Studies suggest that the prevalence of HIV is higher among long term marital/consensual relationships than in the unmarried. We assessed the risk of incident HIV infection by marital status in rural Rakai, Uganda.
Design
Longitudinal data from the Rakai Community Cohort Study (RCCS) between 1999 - 2011
Methods
We estimated HIV incidence per 100 person years (py) in sexually active individuals aged 15-49 with a total of 44,179.6 person years (py) who were never married (females 2,929py, males 4,261py), currently married or in long-term consensual relationships (“currently married females 29,823py, males 21,299py) and previously married (females 3,563py, males 1,475). Poisson multivariable regression was used to estimate the unadjusted and adjusted incident rate ratios (IRRs) and 95% confidence intervals (95% CI) of HIV acquisition.
Results
HIV incidence among currently married persons was 0.93/100py, which was lower than the never married (1.51/100py) and previously married (2.85/100py). The risk of HIV acquisition was significantly lower in the currently married compared to the never married among women (Adj IRR=0.26, 95% CI: 0.16-0.42), but not men (Adj IRR=0.69, 95% CI: 0.31-1.52). HIV incidence was lower among first marriages (0.73/100py) compared to second or higher order marriages (1.38/100py). Multiple sex partners significantly increased the risk of HIV acquisition in both women (Adj IRR=2.53, 95% CI: 1.6, 3.97) and men (Adj IRR=1.77, 95% CI: 1.20-2.60).
Conclusion
Current marriage especially first order marriage was associated with reduced risk of HIV acquisition in women, but not in men, and multiple sex partnerships increased HIV risk for both sexes.
Keywords: Marriage, HIV infection, Uganda
Introduction
It is estimated that over 2.3 million people are newly infected with HIV per year [1, 2], and most new infections occur in Sub-Saharan Africa, mainly as a result of unprotected heterosexual intercourse. A large proportion of prevalent HIV infections are among people in long-term marital or consensual relationships, and several studies suggest that marriage is associated with the risk of prevalent HIV, especially in women [3-11]. However, it is unclear whether HIV infection precedes entry into marriage or whether it is a consequence of marriage since differences in the duration of exposures between the unmarried and married states affect the estimated risk of prevalent infection associated with marriage. One Ugandan study found that the risk of incident HIV did not differ between never married and currently married women, but was increased in the previously married [12, 13]. We are not aware of other studies that assessed incident HIV by marital status.
Therefore, we investigated the rates of incident HIV infection among never, currently and previously married individuals; and determined whether entry into marriage affected the risk of new HIV infections in rural Rakai district, southwestern Uganda.
Methods
Rakai district in southwestern Uganda bordering Tanzania and Lake Victoria, is a rural area with a population of approximately 470,000, and marriage or long-term cohabitation is almost universal among adults. Marriage is patrilineal since children belong to the father's family and patrilocal because wives move to their husband's place of residence [25]
Data collected by the Rakai Community Cohort Study (RCCS) between 1999 and 2011 were used for this analysis. The RCCS is an open cohort with approximately annual surveys of 14,000 consenting persons aged 15-49 years, resident in 50 communities, and has been ongoing since 1994 and has been described elsewhere [26, 27]. In brief, census prior to each survey round identify eligible participants who are then contacted in their homes or invited to attend at central locations (“hubs”) for interview and provision of blood for HIV diagnosis. Interviews ascertain information on socio demographic characteristics, sexual behaviors and health every 12 to 18 months using structured questionnaires administered in private by same sex interviewers. Approximately 95% of persons resident at the time of survey complete interviews and sample collection. Participants were asked whether they had ever married or were in a long-term consensual relationship (henceforth referred to as “married”), and for those who responded affirmatively, their current and previous marital status was ascertained. Persons at the time of interview who were separated, divorced or widowed were classified as “previously married”. Thus, marital status was categorized as never, currently and previously married at enrollment at the beginning of each time period. Employment status was classified as agriculture, skilled/professional, non-skilled and other. Data were stratified into three study periods each comprised of three study rounds with varying duration; 2000-2002; 2003-2006 and 2007-2011 to assess temporal trends. Data on marital order (i.e., the number of times a person had married) were collected since 2006 and were used to determine the effect of re-marriage on HIV infection.
In separate analyses to assess the effects of entry into a first marriage (newly married), never married persons identified at the beginning of the interval were followed over time to determine whether they became newly married/entered into a first marriage or initiated a long-term consensual relationship during follow up. We then determined HIV incidence among newly and never married individuals during the interval of exposure among newly married and never married individuals.
HIV diagnosis used two enzyme immunoassays (EIAs) confirmed by Western Blot for seroincident cases. HIV incidence was estimated per 100 person years (py) of observation in initially uninfected persons assuming that infection occurred at the midpoint between the last negative and first positive HIV test. Poisson multivariable regression with person years as an offset was used to estimate the incidence rate ratios (IRR) and 95% confidence intervals (95%CI) of HIV acquisition stratified by gender. Age and education were adjusted for and since there was no significant change in the results they remained in the model due to the epidemiological importance of these covariates to the outcome. And since marital status is likely to be influenced by age, education, and residence, interaction terms between marital status and these covariates were assessed but no interactions were statistically significant and were excluded from the final analysis. Analyses were conducted in STATA™, version 9 (College Station Texas)
Results
Table 1 shows the distribution of participants by sex, marital status categories and socio-behavioral factors. The majority of participants were currently married, both among females (82.0%) and males (78.7%), and the population was predominantly rural (35518/38441, 92.4%). There were marked differences in the distribution of socio demographic and behavioral characteristics between never, currently and previously married persons. The mean interval between survey rounds was ∼1.5 years, and the retention rate was ∼75%.
Table 1. Percent distribution of number of participants by marital status, gender and socio-behavior characteristics.
| Female | Male | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Never Married | Currently Married | Previously married | Never Married | Currently Married | Previously married | |||||||||||||||
| Characteristics | No exposed | % | No exposed | % | No exposed | % | No exposed | % | No exposed | % | No exposed | % | ||||||||
| All | 2033/24944 | 8.15 | 20464/24944 | 82.04 | 2447/24944 | 9.81 | 2850/17946 | 15.88 | 14122/17946 | 78.7 | 974/17946 | 5.4 | ||||||||
| Study Period | ||||||||||||||||||||
| 2000-2002 | 535/5829 | 9.18 | 4785/5829 | 82.09 | 509/5829 | 8.73 | 741/4571 | 16.21 | 3633/4571 | 79.48 | 197/4571 | 4.31 | ||||||||
| 2003-2006 | 727/8253 | 8.80 | 6699/8253 | 81.17 | 827/8253 | 10.02 | 964/5689 | 16.94 | 4428/5689 | 77.83 | 297/5689 | 5.22 | ||||||||
| 2007-2011 | 771/10862 | 7.10 | 8980/10862 | 82.67 | 1111/10862 | 1023 | 1145/7686 | 14.90 | 6061/7686 | 78.86 | 480/7686 | 6.25 | ||||||||
| Place of residence | ||||||||||||||||||||
| Rural | 1546/20495 | 7.54 | 17040/20495 | 83.14 | 1909/20495 | 9.31 | 2277/15023 | 15.16 | 11951/15023 | 79.55 | 795/15023 | 5.29 | ||||||||
| Semi-urban | 487/4449 | 10.95 | 3424/4449 | 72.92 | 538/4449 | 12.09 | 573/2923 | 19.60 | 2171/2923 | 74.27 | 179/2923 | 6.12 | ||||||||
| Age in years | ||||||||||||||||||||
| 15-19 | 497/1403 | 35.42 | 876/1403 | 62.44 | 30/1403 | 2.14 | 760/811 | 93.71 | 48/811 | 5.92 | 3/811 | 0.37 | ||||||||
| 20-24 | 626/5488 | 11.41 | 4661/5488 | 84.93 | 201/5488 | 3.66 | 1292/2761 | 46.79 | 1371/2761 | 49.66 | 98/2761 | 3.55 | ||||||||
| 25-29 | 455/6193 | 7.35 | 5293/6193 | 85.47 | 445/6193 | 7.35 | 537/3979 | 13.50 | 3191/3979 | 80.20 | 251/3979 | 6.31 | ||||||||
| 30+ | 455/11860 | 3.84 | 9634/11860 | 81.23 | 1771/11860 | 14.93 | 261/10395 | 2.51 | 9512/10395 | 91.51 | 622/10395 | 5.98 | ||||||||
| Education | ||||||||||||||||||||
| None | 49/1826 | 2.68 | 1545/1826 | 84.61 | 232/1826 | 12.71 | 63/617 | 10.21 | 493/617 | 79.90 | 61/617 | 9.89 | ||||||||
| Primary | 828/16095 | 5.14 | 13504/16095 83.90 | 1763/16095 | 10.95 | 1523/11189 | 13.61 | 8964/11189 | 80.11 | 702/11189 | 6.27 | |||||||||
| Sec and above | 1156/7023 | 16.46 | 5415/7023 | 77.10 | 452/7023 | 6.44 | 1264/6140 | 20.59 | 4665/6140 | 75.98 | 211/6140 | 3.44 | ||||||||
| Age at sex debut | ||||||||||||||||||||
| <15 years | 522/6341 | 8.23 | 4995/6341 | 78.77 | 824/6341 | 12.99 | 1033/3014 | 34.27 | 1798/3014 | 59.65 | 183/3014 | 6.07 | ||||||||
| 15-17 years | 991/13486 | 7.35 | 11263/13486 | 83.52 | 1232/13486 | 9.14 | 1238/7767 | 15.94 | 6097/7767 | 78.50 | 432/7767 | 5.56 | ||||||||
| 18+ | 520/5117 | 10.16 | 4206/5117 | 82.20 | 391/5117 | 7.64 | 579/7345 | 7.88 | 6227/7345 | 84.78 | 359/7345 | 4.89 | ||||||||
| Age at Marriage * | ||||||||||||||||||||
| <15 years | N/A | 1295/1536 | 84.31 | 241/1536 | 15.69 | N/A | 9/9 | 100.00 0 | 0.00 | |||||||||||
| 15-17 years | N/A | 8460/9450 | 89.52 | 990/9450 | 10.48 | N/A | 476/505 | 92.48 | 29/505 | 5.74 | ||||||||||
| 18+ | N/A | 9873/11004 | 89.72 | 1131/11004 | 10.28 | N/A | 12997/13889 | 93.58 | 892/13889 | 6.42 | ||||||||||
| Number of partners in past year | ||||||||||||||||||||
| One | 1852/23994 | 7.72 | 19934/23994 | 83.08 | 2208/23994 | 9.20 | 1542/9876 | 15.61 | 7837/9876 | 79.35 | 497/9876 | 5.03 | ||||||||
| 2 or More | 181/950 | 19.05 | 530/950 | 55.79 | 239/950 | 25.16 | 1308/8070 | 16.21 | 6285/8070 | 77.88 | 477/8070 | 5.91 | ||||||||
| Alcohol use in past year | ||||||||||||||||||||
| Yes | 392/5081 | 7.72 | 3998/5081 | 78.69 | 691/5081 | 13.60 | 593/6431 | 9.22 | 5431/6431 | 84.45 | 407/6431 | 6.33 | ||||||||
| No | 1641/19863 | 8.26 | 16466/19863 | 82.90 | 1756/19863 | 8.84 | 2257/11515 | 19.60 | 8691/11515 | 75.48 | 567/11515 | 4.92 | ||||||||
| Condom use in past year** | ||||||||||||||||||||
| Never | 94/1942 | 1716/1942 | 88.36 | 132/1942 | 6.80 | 22/747 | 2.95 | 704/747 | 92.24 | 17/747 | 2.28 | |||||||||
| Inconsistent | 351/6789 | 5840/6789 | 86.02 | 598/6789 | 8.81 | 545/4907 | 11.11 | 4362/4907 | 88.90 | 287/4907 | 5.85 | |||||||||
| Consistent | 133/469 | 182/469 | 38.81 | 154/469 | 32.84 | 313/496 | 63.10 | 102/496 | 20.56 | 81/496 | 16.33 | |||||||||
| Age difference in partners | ||||||||||||||||||||
| Same Age | 1489/20500 | 16933/20500 | 82.60 | 2078/20500 | 10.14 | 2143/14682 | 14.60 | 11733/14682 | 79.91 | 806/14682 | 5.49 | |||||||||
| 1-4 years | 451/3072 | 2377/3072 | 77.38 | 244/3072 | 7.94 | 679/2904 | 23.38 | 2071/2904 | 71.32 | 154/2904 | 5.30 | |||||||||
| 5+ years | 93/1372 | 1154/1372 | 84.11 | 125/1372 | 9.11 | 28/360 | 7.78 | 318/360 | 88.33 | 14/360 | 3.89 | |||||||||
Data on baseline participants only;
For those who ever used;
Table 2 shows new HIV cases, person-years and HIV incidence rates stratified by gender, marital status and socio-demographic covariates. The majority of incident HIV infections in both women (60.7%) and men (71.0%) occurred during follow up of currently married persons who constituted the majority of observation time (76.1% for women and 74.2% for men). In women, the incidence of HIV among the currently married was 0.86/100py, which was lower than in the never married (2.29/100py) and previously married (2.86/100py). The incidence of HIV in currently married women was lower than in the never and previously married regardless of time periods, place of residence, age and educational groups. Among men, HIV incidence was similar in the never (1.08/100 py) and currently married (0.99/100 py), and both were lower than in the previously married (2.71/100 py), but differentials in male incidence by marital status were not consistent across socio-demographic covariates. For example, among men during the time period 2002-06 and those aged 20-24, incidence was lower in the never than the currently married, although these differences were not statistically significant (p=0.12 and p=0.23, respectively). HIV incidence among persons in monogamous union was lower and similar for both females (200/25470.65, 0.79/100py) and males (202/20506.23, 0.99/100py) compared to those in polygamous relationships (106/8915.86, 1.19/100pyo in women; 57/3992.24, 1.43/100pyo in men). However, HIV incidence in women who reported multiple sex partners was twice as high (2.35/100pyo) as those who were in polygamous unions and was not different by union type among men (table 3).
Table 2. HIV incidence stratified by marital status and sex, by time period and socio-demographic characteristics.
| Female | Male | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Never Married | Currently Married | Previously Married | Never Married | Currently Married | Previously Married | |||||||
| Characteristics | Cases/py | rate | cases/py | rate | Cases/py | rate | cases/py | rate | cases/py | rate | cases/py | rate |
| All | 67/2928.96 | 2.29 | 261/29822.63 | 0.86 | 102/3562.67 | 2.86 | 46/4260.73 | 1.08 | 211/21298.52 | 0.99 | 40/1475.10 | 2.71 |
| Study Period | ||||||||||||
| 2000-2002 | 9/609.55 | 1.48 | 48/5288.63 | 0.91 | 18/565.64 | 3.18 | 11/861.76 | 1.28 | 36/4110.91 | 0.88 | 8/224.91 | 3.56 |
| 2003-2006 | 24/994.93 | 2.41 | 94/9051.76 | 1.04 | 29/1120.87 | 2.59 | 12/1357.88 | 0.88 | 92/6292.66 | 1.46 | 8/416.49 | 1.92 |
| 2007-2011 | 34/1324.48 | 2.57 | 119/15482.23 | 0.77 | 55/1876.17 | 2.93 | 23/2041.08 | 1.11 | 83/10893.96 | 0.76 | 24/833.70 | 2.88 |
| Place of residence | ||||||||||||
| Rural | 49/2224.39 | 2.20 | 203/24686.11 | 0.82 | 75/2762.07 | 2.72 | 38/3402.51 | 1.12 | 160/17978.15 | 0.89 | 27/1210.71 | 2.23 |
| Semi-urban | 18/704.57 | 2.55 | 58/5136.51 | 1.13 | 27/800.60 | 3.37 | 8/858.22 | 0.93 | 51/3320.38 | 1.55 | 13/264.40 | 4.92 |
| Age in years | ||||||||||||
| 15-19 | 10/706.79 | 1.41 | 11/1135.25 | 0.97 | 2/40.75 | 4.91 | 6/1094.46 | 0.55 | 0/64.56 | 0.00 | 0/5.41 | 0.00 |
| 20-24 | 25/878.60 | 2.85 | 67/6516.55 | 1.03 | 19/296.16 | 6.41 | 18/1954.75 | 0.92 | 27/1963.48 | 1.38 | 9/141.92 | 6.34 |
| 25-29 | 23/656.16 | 3.51 | 78/7801.69 | 1.00 | 23/637.10 | 3.61 | 16/809.95 | 1.98 | 65/4701.95 | 1.38 | 8/372.16 | 2.15 |
| 30+ | 9/687.40 | 1.31 | 105/14369.14 | 0.73 | 58/2588.66 | 2.24 | 6/401.56 | 1.49 | 119/14565.05 | 0.82 | 23/955.61 | 2.41 |
| Education | ||||||||||||
| None | 1/70.02 | 1.43 | 20/2230.23 | 0.90 | 12/332.02 | 3.61 | 0/91.43 | 0.00 | 13/728.73 | 1.78 | 1/95.36 | 1.12 |
| Primary | 29/1186.91 | 2.44 | 166/19501.54 | 0.85 | 77/2536.14 | 3.04 | 32/2302.86 | 1.39 | 154/13452.36 | 1.14 | 33/1074.37 | 3.07 |
| Sec and above | 37/1672.03 | 2.21 | 75/8090.86 | 0.93 | 13/694.51 | 1.87 | 14/1866.39 | 0.75 | 44/7117.47 | 0.62 | 6/305.37 | 1.96 |
P<0.05
P<0.01
P<0.001
Table 3. HIV incidence stratified by marital status and gender, by risk behaviors.
| Female | Male | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Never Married | Currently Married | Previously Married | Never Married | Currently Married | Previously Married | |||||||
| Characteristics | cases/py | rate | cases/py | rate | Cases/py | rate | cases/py | rate | cases/py | rate | cases/py | rate |
| All | 67/2928.96 | 2.29 | 261/29822.63 | 0.86 | 102/3562.67 | 2.86 | 46/4260.73 | 1.08 | 211/21298.52 | 0.99 | 40/1475.10 | 2.71 |
| Age at sex debut | ||||||||||||
| <15 years | 17/792.36 | 2.15 | 91/7163.46 | 1.27 | 36/1184.78 | 3.04 | 14/1591.40 | 0.88 | 29/2774.87 | 1.04 | 9/274.36 | 3.28 |
| 15-17 years | 35/1407.37 | 2.49 | 134/16371.87 | 0.82 | 52/1801.61 | 2.89 | 19/1840.07 1 | 1.03 | 115/9179.62 | 1.25 | 20/655.69 | 3.05 |
| 18+ | 15/729.23 | 2.06 | 36/6287.30 | 0.57 | 14/576.28 | 2.43 | 13/829.25 | 1.57 | 67/93344.04 | 0.72 | 11/545.05 | 2.02 |
| Age at marriage** | ||||||||||||
| <15 years | N/A | 30/1845.32 | 1.62 | 10/347.00 | 2.88 | N/A | 0/11.95 | 0.00 | 0/0.00 | NA | ||
| 15-17 years | N/A | 95/12151.91 | 0.78 | 39/1426.13 | 2.73 | N/A | 12/714.54 | 1.68 | 1/43.73 | 2.29 | ||
| 18+ | N/A | 127/14427.96 | 0.88 | 51/1648.14 | 3.09 | N/A | 188/19495.64 | 0.19 | 36/1345.93 | 2.67 | ||
| Number of partners in past year | ||||||||||||
| One | 56/2674.05 | 2.09 | 242/29014.60 | 0.83 | 77/3221.36 | 2.39 | 18/2307.33 | 0.78 | 78/11768.31 | 0.66 | 17/758.20 | 2.24 |
| 2 or More | 11/254.91 | 4.32 | 19/808.03 | 2.35 | 25/341.31 | 7.32 | 28/1953.40 | 1.43 | 133/9530.22 | 1.40 | 23/716.91 | 3.21 |
| Alcohol use in past year | ||||||||||||
| Yes | 14/514.91 | 2.72 | 55/5314.83 | 1.03 | 27/924.59 | 2.92 | 17/813.60 | 2.09 | 98/7490.53 | 1.31 | 16/561.35 | 2.85 |
| No | 53/2414.06 | 2.20 | 206/24507.79 | 0.84 | 75/2638.08 | 2.84 | 29/3447.12 | 0.84 | 113/13807.99 | 0.82 | 24/913.75 | 2.63 |
| Condom use in past year* | ||||||||||||
| Never | 3/166.50 | 1.80 | 15/2942.01 | 0.63 | 3/226.64 | 1.32 | 1/42.01 | 2.38 | 8/1264.86 | 0.63 | 1/30.05 | 3.33 |
| Inconsistent | 24/597.12 | 4.02 | 84/10050.81 | 0.83 | 34/1012.50 | 3.56 | 11/981.39 | 1.12 | 66/7813.43 | 0.84 | 17/493.89 | 3.44 |
| Consistent | 1/231.69 | 0.43 | 4/315.26 | 1.27 | 3/256.48 | 1.17 | 4/551.90 | 0.72 | 2/179.75 | 1.11 | 3/143.78 | 2.09 |
| Age difference in partners | ||||||||||||
| Same Age | 48/2075.01 | 2.31 | 210/24393.49 | 0.86 | 79/2985.38 | 2.65 | 31/3121.23 | 0.99 | 176/17689.34 | 0.99 | 33/1217.21 | 2.78 |
| 1-4 years | 18/703.43 | 2.56 | 33/3679.01 | 0.90 | 16/373.28 | 4.29 | 13/1100.01 | 1.18 | 32/3144.89 | 1.02 | 7/238.96 | 2.93 |
| 5+ years | 1/150.52 | 0.66 | 18/1750.13 | 1.03 | 7/204.01 | 3.43 | 2/39.48 | 5.07 | 34/464.30 | 0.65 | 0/18.93 | 0.00 |
For those who ever used;
Data on baseline participants only
Table 3 shows HIV incidence stratified by marital status and risk behaviors. Currently married women had lower HIV incidence than the never married and previously married women irrespective of age at sexual debut, age at marriage, numbers of sexual partners and alcohol use before sex. The marital status differentials in HIV incidence were less consistent when stratified by condom use and age differentials between partners. Among men, those currently married had lower HIV incidence than the previously married for all strata of covariates, and in most cases never married men had incidence rates similar to those of currently married men.
The univariate and multivariable analyses are presented in table 4. Currently married women were at significantly lower risk of HIV infection compared to the never married (Adj IRR=0.26, 95% CI: 0.16, 0.42), but there was no statistically significant difference in risk of incident HIV between the never and previously married women. Among men, there were no statistically significant differences in risk of incident HIV between the currently married and never married (Adj IRR 0.70, 95%CI 0.31-1.59), but previously married men were at significantly higher risk of HIV acquisition than never married men (Adj IRR 2.62, 95%CI 1.13-6.13). Multiple sex partners significantly increased HIV risk in both men (Adj IRR=1.79, 95% CI: 1.20, 2.65) and women (Adj IRR=2.30, 95% CI: 1.45, 3.63). Urban residence was a significant predictor of HIV risk in men (Adj IRR 1.87, 95% CI: 1.20, 2.92), but not in women (Adj IRR=1.11, 95% CI: 0.76, 1.63).
Table 4. Unadjusted and Adjusted HIV incident rate ratios stratified by gender.
| Female | Male | |||
|---|---|---|---|---|
| Unadjusted IRR (95% CI) | Adjusted IRR (95% CI) | Unadjusted IRR (95% CI) | Adjusted IRR (95% CI) | |
| Marital Status | ||||
| Never Married | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| Currently Married | 0.43*** (0.33 0. 55) | 0.26*** (0.16 0.42) | 0.96 (0.71 1.30) | 0.70 (0.31 1.59) |
| Previously married | 1.37* (1.02 1.84) | 0.85 (0.50 1.44) | 2.52*** (1.68 3.78) | 2.62* (1.13 6.13) |
| Age years | ||||
| 15-19 | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| 20-24 | 0.93 (0.64 1.37) | 1.61 (0.66 3.93) | 2.17* (1.04 4.54) | 2.89 (0.67 12.36) |
| 25-29 | 0.94 (0.64 1.37) | 2.04 (0.84 5.00) | 2.6.0** (1.27 5.34) | 2.45 (0.53 11.42) |
| 30+ | 0.67* (0.46 0.97) | 1.45 (0.60 3.50) | 1.52 (0.75 3.09) | 2.61 (0.57 11.89) |
| Education | ||||
| Never | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| Primary | 0.95 (0.68 1.34) | 1.09 (0.59 2.02) | 0.89 (0.53 1.51) | 2.42 (0.59 9.99) |
| Secondary and above | 0.94 (0.66 1.36) | 1.07 (0.54 2.12) | 0.51* (0.29 0.88) | 1.30 (0.30 5.65) |
| Age at sexual debut | ||||
| Less than 15 | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| 15-17 | 0.69*** (0.57 0.83) | 0.77 (0.54 1.10) | 1.16 (0.86 1.56) | 1.48 (0.88 2.48) |
| 18+ | 0.53*** (0.41 0.70) | 0.69 (0.44 1.09) | 0.73 (0.53 1.01) | 1.07 (0.60 1.94) |
| Number of partners | ||||
| One | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| 2 or More | 3.54*** (2.72 4.62) | 2.30*** (1.45 3.63) | 2.05*** (1.64 2.56) | 1.79** (1.20 2.65) |
| Alcohol Consumption | ||||
| Yes | 1.30* (1.05 1.61) | 1.47 (0.81 2.64) | 1.65*** (1.33 2.05) | 0.67 (0.30 1.49) |
| No | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| Condom use | ||||
| Never | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| Inconsistent | 1.78** (1.18 2.69) | 1.70* (1.07 2.70) | 1.20 (0.68 2.14) | 0.96 (0.49 1.89) |
| Consistent | 1.60 (0.77 3.20) | 0.82 (0.34 1.96) | 1.31 (0.59 2.92) | 0.84 (0.31 2.25) |
| Age diff in partners | ||||
| Same age | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| 1-4 years | 1.23 (0.94 1.60) | 1.47 (0.99 2.20) | 1.06 (0.79 1.44) | 1.22 (0.79 1.88) |
| 5+ Years | 1.08 (0.72 1.61) | 1.13 (0.65 1.95) | 0.88 (0.36 2.13) | 0.40 (0.05 2.95) |
| Area of residence | ||||
| Rural | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| Semi-Urban | 1.38** (1.12 1.70) | 1.11 (0.76 1.63) | 1.61*** (1.25 2.07) | 1.87** (1.20 2.92) |
P<0.05
P<0.01
P<0.001
Effect of Entry into First Marriage and risk of HIV infection
HIV prevalence among those women entering into a first marriage was 11.6% (98/848) which was higher than in women who remained unmarried 7.5%, (969/12888, p<0.001). Similarly, men entering into a first marriage had higher HIV prevalence 5.6% (82/1472) than men who remained unmarried, 2.1% (341/16266, p<0.001). Newly married women had a lower incidence of HIV infection (1.67/100py, 13/780.5 py) compared to women who remained unmarried (2.17/100py, 73/3369.9 py), but this difference was not statistically significant (Adj IRR 0.77, 95%CI 0.42-1.39). HIV incidence among newly married men (1.59/100py, 22/1382.7 py) was higher than in men who remained unmarried (1.07/100py, 51/4779 py), but this was not statistically significant (Adj IRR=1.22, 95%CI 0.72-2.07).
Effect of prior marriage on risk of HIV infection
HIV incidence among women in their first marriage (0.73/100py, 111/15187 py) was lower than in those who reported second or higher order marriages (1.38/100py, 32/2318.7 py, p=0.002). In men, incidence was 0.67/100py (46/6867.4 py) in first order marriages and 1.06/100py (57/5383.4 py) in men with two or more marriages (p=0.013). In reference to never married, first marriage was significantly protective against HIV infection in women (Adj IRR=0.32, 95% CI: 0.23-0.45) compared to men (Adj IRR=0.67, 95% CI: 0.39-1.17) and persons in second order or higher (Adj IRR=0.65, 95% CI: 0.42-1.01 in women and Adj IRR=1.23, 95% CI:0.69-2.21 among men). Irrespective of marital order, the incidence of HIV among married women was lower than in women who remained unmarried 2.16/100 py, 73/3373.8 py). Relative to women who had never married, the risk of HIV acquisition was lower in first marriages (Adj IRR=0.32, 95% CI: 0.23 0.45) and in higher order female marriages (AdjIRR 0.65, 95%CI 0.42-1.01). However, in men HIV risk did not differ significantly by marital order when compared to the never married.
Discussion
We found that the incidence of HIV was significantly lower in currently married women relative to the never married, and entry into a first marriage did not significantly affect HIV incidence relative to women who remained unmarried. For men, HIV incidence was comparable in the currently married and never married groups. HIV incidence was highest for both men and women who had experienced marital dissolution, although the risk for women was attenuated after adjustment for risk behaviors.
These findings are consistent with previous Rakai data that the incidence of HIV is higher among persons who were not currently married [21], but they are in contrast with previous reports suggesting that marriage constitutes a risk for prevalent HIV [3, 7-10]. However, HIV prevalence is a cumulative measure and cannot account for the differentials in the duration of exposure to risk of HIV in each marital state. Since the interval between sexual debut and marriage is relatively short in Rakai (∼ 2.1 years for women and 5.2 years for men), compared to the mean duration of marriage in this population (approximately 9.0 years for women and 9.4 years for men), cumulative HIV prevalence is invariably lower prior to marriage than during marriage due to the shorter duration of exposure. Nevertheless, because of the longer duration of marital state, 60.7% of female incident infections and 71.0% of male infections occurred among the currently married. The mechanism whereby marriage may be protective from incident HIV for women are unknown, but it is noteworthy that fewer married women reported two or more sex partners in the prior year (2.7%), whereas two or more partners were frequently reported by the never (8.7%) and previously married women (10.6%). In contracts, among men, multiple partnerships were frequent and comparable among the never, currently and previously married (43.5%, 44.7% and 48.6%, respectively, Table 3). Thus, differentials in the number of sex partners by marital status may protect married women, but there were no comparable differentials observed among males.
However, HIV prevalence was higher among men and women who had entered into a first marriage than those remaining unmarried, which possibly reflects previous high risk behaviors among the newly married prior to initiation of observation. However, the incidence of HIV was not-significantly different between those entering a first marriage and those who remained unmarried suggesting that entry into marriage per se did not increase risk. Other risk factors for HIV such as multiple sex partners, alcohol consumption and urban residence were consistent with prior findings [10, 13, 28 - 30]. In addition, the finding of higher HIV incidence among persons in second or higher order marriages than those in their first marriages is consistent with the higher incidence observed in persons who experienced marital dissolution prior to remarriage.
The strategy of ABC (Abstinence, Be faithful and use of condoms) may be difficult to practice within marriage, since a woman's status often depends on childbearing, making abstinence and condom use in marriage culturally inappropriate [7]. In many societies, multiple sexual partners are condoned for men, while women are expected to remain faithful [14, 15], and unprotected sex with extramarital partners is a risk factor for HIV infection [16-22]. Wide age disparities between spouses (e.g >10 years age difference) could contribute to risk if younger women marry older men who are more likely to be infected, and age disparities could reduce a woman's ability to negotiate safer sex behaviors such as condom use increasing risk of HIV infection [23-25]. It is programmatically important to determine subgroups of the population most at risk in order to target intervention.
These findings have implications for targeting of HIV prevention initiatives. If as suggested by these and other data [22], HIIV incidence is highest in never married women and previously married persons of both genders, interventions should be targeted on these subpopulations most at risk of acquisition.
In summary, in this rural Ugandan society currently married women were at decreased risk of incident HIV compared to the never married or those who had experienced marital dissolution.
Acknowledgments
We thank the staff of Rakai Health Sciences Program; the RCCS study participants, the Rakai District Directorate of Health services and the Director, Uganda Virus Research Institute for supporting this work
Disclosure of Funding: NIH, Division of Allergy and Infectious Diseases; Bill and Melinda Gates Foundation; Department of the Army, United States Army Medical Research and Material Command Cooperative Agreement, the Henry M. Jackson Foundation; Fogarty International Center/USNIH- AITRP
Footnotes
Conflict of interest: None Declared
Contributing authors: F Nalugoda, lead author contributed to the design and implementation of the study and was responsible for data management, analysis, interpretation and manuscript development. RH Gray, JB Bwanika, X Kong, FE Makumbi, FW-Mangen, D Guwatudde and T Lutalo contributed to analysis, interpretation and manuscript development. DM Serwadda, MJ Wawer, NK Sewankambo, J Kagaayi, G Kigozi and RH Gray contributed to the design, implementation and manuscript development.
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