YOUNG women in Zimbabwe have a higher risk of HIV infection if they have a sexual partner who is 10 or more years older than them, investigators have reported in the online edition of AIDS.
BY PHYLLIS MBANJE
Such inter-generational relationships increased the risk of contracting HIV by approximately 75%.
“We found that age-disparate sexual relationships are associated with increased HIV incidence among young women aged
15 to 24 years, particularly where partners are 10 or more years older,” comment the authors. “Although, only a minority of young women reported partners ten or more years older, the proportion was still substantial (21%)… so these inter-generational relationships are likely to be an important contributor to new infections in young women and to the HIV epidemic in this setting,” reads the report in part.
The investigators called for a roll-out of interventions, including pre-exposure prophylaxis (PrEP), to reduce the HIV risk for young women in relationships with significantly older men.
Young women in sub-Saharan Africa have very high rates of HIV infection.
In Zimbabwe, the incidence of HIV among women aged 15 to 24 years is twice as high as that observed in men of the same age group.
There is a widespread phenomenon of “blessers”, whereby, older partners treat young girl to shopping sprees and buy them expensive cars and clothing.
It seems the phenomenon has gone viral, with many young women looking for older men to sponsor their expensive lifestyles.
“Most young girls portray a fake lavish lifestyle and so to keep up appearances they get involved with blessers, who will indulge their whims,” a student from Midlands State University in Gweru said.
Modelling studies have shown that sexual relationships with older men — or age-disparate relationships — could be a major reason why young women have such high HIV incidence rates.
This is because HIV prevalence is higher among older men than younger ones, meaning that young women in relationships with older men are more likely to be exposed to HIV.
However, the precise impact of age-disparate relationships on HIV risk is not fully understood.
An international team of investigators, therefore, examined data collected between 1998 and 2013 in eastern Zimbabwe to see if having an older male sexual partner was associated with an increased risk of infection with HIV for women aged between 15 and 24 years.
Women included in the study were HIV-negative at baseline and completed at least two follow-up visits.
At each visit, social and economic data were collected and if sexually active, participants were asked about the age of their most recent sexual partner.
Relationships were categorised as age-homogenous if there was a zero to four years difference; intra-generational if the difference was between five to nine years; and inter-generational if the partner was at least 10 years older.
The investigators performed a set of analyses to see if age and other social, economic and sexual risk factors were associated with an increased risk of HIV incidence.
A total of 3 082 women met the inclusion criteria and contributed 3 746 study visits.
There were 126 new HIV infections during 8 777 person-years of follow-up, a rate of 1,43 per 100 person-years.
In all, 2 262 study visits involved women who reported sexual activity, and 1 734 of these yielded data on the age of the most recent sexual partner.
Just over a fifth of the women (21%) had a partner who was 10 or more years older and 45% had a partner who was five to nine years older.
These proportions remained steady during the study.
HIV prevalence in men declined over time, but remained constantly higher among men aged 30 years and older.
Age difference was associated with higher HIV incidence among younger women.
Each one-year difference in age increased the risk by 5%.
Incidence was higher in inter-generational relationships (2,56 per 100 person-years) compared to age-homogeneous relationships (1,49 per 100 person-years).
Similar patterns were also found when the investigators took into account factors such as area of residence (urban, peri-urban, rural), household income, wealth and orphanhood.
Women with a secondary education were significantly less likely to report an inter-generational relationship, compared to women with lower levels of education.
Inter-generational sexual relationship was associated with the older male having a concurrent sexual partner, and there was a trend for this to be associated with higher HIV incidence among young women.
The association between inter-generational relationships did not change as antiretrovirals were rolled out across Zimbabwe.
“As far as we are aware, this is the first study to demonstrate an association between increasing partner age and HIV incidence in a representative general-population sample covering pre- and post-ART [antiretroviral therapy] periods,” note the authors.
“The results from this study provide evidence that age-disparate relationships can be an important contributor to the continued high HIV incidence rates in adolescent girls and young women in sub-Saharan African populations.”