Trends in concurrency, polygyny, and multiple sex partnerships during a decade of declining HIV prevalence in eastern Zimbabwe.
BACKGROUND
Observed declines in the prevalence of human immunodeficiency virus (HIV) infection in Zimbabwe have been attributed to population-level reductions in sexual partnership numbers. However, it remains unknown whether certain types of sex partnerships were more important to this decline. Particular debate surrounds the epidemiologic importance of polygyny (the practice of having multiple wives).


METHODS
We analyze changes in reported multiple partnerships, nonmarital concurrency, and polygyny in eastern Zimbabwe during a period of declining HIV prevalence, from 1998 to 2011. Trends are reported for adult men (age, 17-54 years) and women (age, 15-49 years) from 5 survey rounds of the Manicaland HIV/STD Prevention Project, a general-population open cohort study.


RESULTS
At baseline, 34.2% of men reported multiple partnerships, 11.9% reported nonmarital concurrency, and 4.6% reported polygyny. Among women, 4.6% and 1.8% reported multiple partnerships and concurrency, respectively. All 3 partnership indicators declined by similar relative amounts (around 60%-70%) over the period. Polygyny accounted for around 25% of male concurrency. Compared with monogamously married men, polygynous men reported higher levels of subsequent divorce/separation (adjusted relative risk [RR], 2.92; 95% confidence interval [CI], 1.87-4.55) and casual sex partnerships (adjusted RR, 1.63; 95% CI, 1.41-1.88).


CONCLUSIONS
No indicator clearly dominated declines in partnerships. Polygyny was surprisingly unstable and, in this population, should not be considered a safe form of concurrency.
Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom.
Jeffrey W
JW
Eaton
Biomedical Research and Training Institute.
Felicia R
FR
Takavarasha
Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Christina M
CM
Schumacher
AIDS and TB Unit, Zimbabwe Ministry of Health and Child Welfare, Harare, Zimbabwe.
Owen
O
Mugurungi
Global Health Program, Bill and Melinda Gates Foundation, Seattle, Washington.
Geoffrey P
GP
Garnett
Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom Biomedical Research and Training Institute.
Constance
C
Nyamukapa
Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom Biomedical Research and Training Institute.
Simon
S
Gregson
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D004243:Divorce / Q000706:statistics & numerical data; D005114:Extramarital Relations; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission; D006801:Humans; D008297:Male; D008393:Marriage; D008875:Middle Aged; D015995:Prevalence; D012306:Risk; D055815:Young Adult; D015030:Zimbabwe / Q000453:epidemiology
HIV; Zimbabwe; behavior change; concurrency; divorce; multiple partnerships; polygyny