| Sexual
behaviour patterns and other risk factors for HIV infection in rural
Tanzania: a case-control study.
Quigley M, Munguti K, Grosskurth H, Todd J, Mosha F, Senkoro K,
Newell J, Mayaud P, ka-Gina G, Klokke A, Mabey D, Gavyole A, Hayes
R.
London School of Hygiene and Tropical Medicine, UK.
OBJECTIVE: To examine the association between HIV infection and
patterns of sexual behaviour and other risk factors in a rural Tanzanian
population in a case-control study, nested within a randomized trial
of improved sexually transmitted disease treatment. METHODS: All
HIV-positive patients from the baseline survey of the randomized
trial were eligible as cases. Cases (n = 338) and controls (a random
sample of one in eight HIV-negative persons; n = 1078) were interviewed
about risk factors for HIV infection using a structured questionnaire.
RESULTS: A significantly higher HIV prevalence was found among men
and women not currently employed in farming [men: odds ratio (OR),
2.08; women: OR, 3.65], women who had travelled (OR, 3.27), educated
women (OR, 4.51), and widowed/ divorced people compared with those
currently married (men: OR, 3.10; women: OR, 3.54). Two spouse-related
factors were significantly associated with HIV, even after adjustment
for the sexual behaviour of the index case: HIV was more prevalent
in men with younger spouses (P = 0.020 for trend) and in women married
to men currently employed in manual work, office work or business
(OR, 2.20). In women only, blood transfusions were associated with
a higher HIV prevalence (OR, 2.40), but only a small population
attributable fraction (4%). There was an increased HIV prevalence
associated with increasing numbers of injections. Reported number
of lifetime sexual partners was significantly associated with HIV
infection (women: OR, 7.33 if > or = 10 lifetime partners compared
with < or = 1; men: OR, 4.35 for > or = 50 compared with <
or = 1). After adjustment for confounders, male circumcision was
associated with a lower HIV prevalence (OR, 0.65; P = 0.11). CONCLUSIONS:
In these rural communities, many HIV infections occur through sexual
transmission. Some people are at high risk of HIV infection through
large numbers of sex partners, whereas some are at risk through
their spouse or regular partner. The role of circumcision in HIV
transmission is unclear. Commercial sex seems to play a negligible
role in HIV transmission in these communities. Our results confirm
marked heterogeneity in HIV risk, indicating the scope for risk
reduction strategies.
|