Ugandan women who have been subject to violence from a
sexual partner are more likely than other women to go on to acquire HIV,
according to a large, longitudinal study from the Rakai cohort, published in
the May 15 issue of AIDS. Women who
had experienced more severe forms of violence, more frequently, or over a
longer period of time had greater risks of HIV infection.
Violence against women is a serious and common human rights
and public health problem, which causes significant morbidity and mortality. 'Intimate
partner violence' (IPV) is one form of violence and has been defined as "behaviour
within an intimate relationship that causes physical, sexual, or psychological
harm, including acts of physical aggression, sexual coercion, psychological abuse
and controlling behaviours".
Several (but not all) cross-sectional studies have
identified an association between intimate partner violence and HIV infection.
However, these 'snapshot' studies are unable to tell us what comes first – the
violence or the HIV.
More reliable are prospective, longitudinal studies and two
such studies have previously been published. Data from a South
African cohort found that experience of physical or sexual IPV increased
the risk of HIV infection (incidence rate ratio 1.51). In a seven-country African cohort,
physical or verbal IPV appeared to increase the risk of infection but this was
not statistically significant (incidence risk ratio 1.69).
In order to better understand the possible role of intimate
partner violence in women’s vulnerability to HIV, Dr Fiona Kouyoumdjian and
colleagues examined a decade’s worth of data from a cohort in Rakai, Uganda. There
were 10,252 female participants who took part in interviews on multiple
occasions and were HIV negative at the first interview. On average, women
stayed in the cohort for five and a half years.
Rakai is a rural district in Uganda and agriculture was the
main occupation for the majority of participants. Half the cohort were under
the age of 24 and two thirds had less than seven years of schooling. Only
one-in-five participants had never been married.
Most of the women (58.9%) had experienced intimate partner
violence (IPV) at least once in their lifetime. In the past year, 16.0% had
experienced sexual IPV, 16.8% physical IPV and 22.4% verbal IPV. Women often
suffered more than one form of violence.
Just under one-in-ten women became HIV positive while in the
cohort. The HIV infection rate was higher for women who had ever experienced
intimate partner violence than for women who had not experienced IPV.
After statistical adjustment, women who had ever experienced
IPV had an incidence rate ratio of 1.55 (95% confidence interval 1.25-1.94).
This is comparable to the results seen in the two previous prospective studies.
Similar statistically significant results were seen for ever experiencing each form of intimate
partner violence (physical, sexual, verbal) as well as for experiencing some
forms of IPV in the past year.
When IPV was recorded as being 'severe' rather than 'minor',
the HIV risk tended to be greater (e.g. ever experiencing severe physical
violence, 1.96 [95% CI 1.46-2.63]).
There was a stepwise relationship between the number of
times a woman experienced intimate partner violence and her increased risk of
HIV infection. For example, women who reported five or more IPV events while in
the cohort had an incidence risk ratio of 1.82 (95% CI 1.06-3.10); women with
more than 20 events had a risk ratio of 3.03 (95% CI 1.83-5.01).
The association between violence and HIV infection could not
be explained by condom use or by partner numbers. When these factors were
controlled for, the association remained the same.
The researchers calculated that the population attributable
fraction of infections that are associated with IPV is 22.2%. In other words,
if intimate partner violence could be eliminated, there would be 22% fewer HIV
infections in this group of women.