Sociodemographic and behavior/risk characteristics explain “effectiveness” of circumcision

In a long description of a recent study investigating the (real world) effectiveness of circumcision, Aidsmap has highlighted important data that reveals an association with sociodemographic (aka cultural and value-based) characteristics and HIV infection risk. The money quotes are as follows.

… Circumcision was significantly associated with tribal affiliation [hence, the common practice among a single group], high school education [perhaps indicating greater knowledge of the perils of unprotected sex], fewer marriages [a likely lower incidence of concurrent partnerships or greater emphasis on serial monogamy?], and a smaller age difference between spouses [indicating a greater power balance within marriage].  

Since the majority of uncircumcised men belonged to the Luo tribe, sociodemographic and behavioural/HIV risk characteristics and HIV incidence rates between Luo and non-Luo males were investigated. Luo males were significantly older [indicating a longer sexual history], more likely to practice traditional African religions, were significantly older than their spouses by more than 10 years, and reported sex with a commercial sex worker. Regardless of the circumcision status, Luo men were 4.6 times more likely to become HIV-infected.

The largely American researchers, possibly exhibiting their pro-circumcision bias, came to the perplexing conclusion, “The findings provide additional evidence that circumcision by traditional circumcisers offers protection from HIV infection in adult men in rural Kenya where circumcision is common.”

A more logical conclusion would be that differences in the ages of spouses, a history of using the services of commercial sex workers, generally more permissive behavioral patterns in sexual relations, and greater power differences between spouses are indicative of greater HIV infection risk. And this we already knew.

Fair use Aidsmap story below the fold.

Traditional circumcision shows protective effect against HIV in rural Kenyan men

Tom Egwang, Tuesday, July 31, 2007

Traditional circumcision protects low-risk rural Kenyan men against HIV infection, according to the findings of a prospective observational study published in the August 1st edition of the Journal of Acquired Immune Deficiency Syndromes.

There is currently a surge of interest worldwide in the possible protection provided by male circumcision against female-to-male HIV transmission in Sub-Saharan Africa. The spotlight on male circumcision has been spurred by three RCTs which demonstrated that circumcision reduced HIV acquisition by 48-61% in Kenyan, Ugandan and South African men.

In Uganda there is active public debate about the usefulness of male circumcision as a tool against HIV/AIDS. Some African countries are already considering how to implement medical circumcision as an HIV prevention policy, following guidance from the World Health Organization.

But there are still many unanswered questions about the effectiveness and safety of circumcision.

One issue is the protective effect of traditional male circumcision. Methods of traditional circumcision vary, as does the amount of tissue removed.

A team of Kenyan and US investigators examined the association between circumcision and new HIV infections in agricultural workers and their dependents in Kenya. The study population is part of the Kericho HIV Cohort Study looking at HIV prevalence, incidence, coinfections, molecular epidemiology, and vaccine feasibility and acceptability.

The study site was a large tea plantation on the outskirts of Kericho, a town in the Rift Valley Province of Kenya. The HIV prevalence in this region stands at 5.3 % by comparison with another Kenyan region with a three-fold greater prevalence. The Kericho study population therefore is considered low risk for HIV infection.

After ethical approval, 2801 adult plantation workers and dependent volunteers aged 18-55 years were recruited over six months beginning in June 2003. After providing informed consent, the participants were enrolled in the baseline cohort and followed every six months for three years with the final follow up ending in December 2006. Extensive baseline sociodemographic, medical, behavioral, and HIV risk data were
collected.

Circumcision status was identified at baseline and recorded as having been carried out by a health care worker, traditional circumciser, or other. All volunteers received pre-and post test counseling.

New HIV infections were identified based on standard HIV test results at each 6-month follow-up. Volunteers with HIV positive results returned for confirmatory testing. Cotrimoxazole prophylaxis and treatment for common medical ailments and opportunistic infections was provided to volunteers.

Out of a total of 1378 men evaluated after two years of follow-up, 80.4% were circumcised. Apart from age, which was similar between 270 uncircumcised and 1108 circumcised men, there were significant differences between the two groups. Circumcision was significantly associated with tribal affiliation, high school education, fewer marriages, and a smaller age difference between spouses.

After two years of follow-up, there were 30 HIV new infections (17 in circumcised and 13 in uncircumcised men). Two-year HIV incidence rates were 0.79 (95% confidence interval [CI]: 0.46 to 1.25) for circumcised men and 2.48 (95% CI: 1.33 to 4.21) for uncircumcised men corresponding to a statistically significant HR = 0.31 (95% CI: 0.15 to 0.64). After adjusting for baseline sociodemographic and behavioral/HIV risks, the protective effect of circumcision still remained significant.

Since the majority of uncircumcised men belonged to the Luo tribe, sociodemographic and behavioural/HIV risk characteristics and HIV incidence rates between Luo and non-Luo males were investigated. Luo males were significantly older, more likely to practice traditional African religions, were significantly older than their spouses by more than 10 years, and reported sex with a commercial sex worker. Regardless of the circumcision status, Luo men were 4.6 times more likely to become HIV-infected.

The majority of circumcised men (73.9%) had been circumcised by traditional circumcisers while the rest had been circumcised by health care workers. The mean age at circumcision was 12.7 years, with a range of 1-28 years. More than half of the circumcised men (62.1 %) were circumcised when they were between 12 and 19 years old.

The findings provide additional evidence that circumcision by traditional circumcisers offers protection from HIV infection in adult men in rural Kenya where circumcision is common.

The policy implication of the study is that attention to cultural practices and preferences such as circumcision have a place alongside safety and efficacy data from conventional RCTs in informing public health policies.

Reference

Shaffer DN et al. The protective effect of circumcision on HIV incidence in rural low-risk men circumcised predominantly by traditional circumcisers in Kenya. J Acquir Immune Defic Syndr 45:371–379, 2007.

http://www.nam.co.uk/en/news/20203C0D-BB7D-49A0-8866-335E65E214F9.asp

About David Wilton

Fronterizo, defense lawyer
This entry was posted in Africa and tagged , , , , , , , , . Bookmark the permalink.

5 Responses to Sociodemographic and behavior/risk characteristics explain “effectiveness” of circumcision

  1. Jake says:

    It’s strange that you find the conclusion ‘puzzling’. Perhaps you didn’t notice, but in the text it is explained that:
    “After adjusting for baseline sociodemographic and behavioral/HIV risks, the protective effect of circumcision still remained significant.”

  2. David says:

    Why did they find that “regardless of the circumcision status, Luo men were 4.6 times more likely to become HIV-infected?”
    Maybe because they didn’t adjust for the sociodemographic baseline in this group? Or is this group just more susceptible?

  3. partly says:

    Some questions for David and the readership:
    1.
    “2801 adult plantation workers and dependent volunteers aged 18-55 years were recruited.”
    “Out of a total of 1378 men evaluated after two years of follow-up”
    Apparently they lost 1423 of the original participants, more than half of them.
    Don’t we need to know more demographically about which participants dropped out?
    2.
    “Extensive baseline sociodemographic, medical, behavioral, and HIV risk data were collected.”
    How many of those initiating enrollment already had HIV? Were they excluded?
    In either case, isn’t this a big problem for this study? If, for example, traditional circumcision spreads HIV through unsanitary conditions (as was found in another study), then wouldn’t this study fail to notice, because those men (particularly the older ones) would already be dead, in no health condition to enroll in a study, or be excluded?

  4. SunkenShip says:

    Ah, the infamous pro-circ Jake has found his way to this blog.
    Great post David as usual.

  5. jan says:

    Regardless of the numbers game and statistics being thrown about Margaret Somerville has said some things on the subject of HIV and the circumcision of children that make good sense to me.
    “To justify, ethically and legally, carrying out surgery on persons unable to consent for themselves, the surgery must be necessary therapy and the least harmful and invasive way to obtain the therapeutic benefit. Routine circumcision fulfils neither of these requirements.”
    “…even assuming that circumcision could help to protect against HIV infection, it would not be necessary to carry it out on unconsenting infants. One could wait until the person was about to become sexually active and could decide for himself.”
    “…one is ethically required to use the least harmful, least invasive means of achieving a good, the achievement of which involves harm. Consequently, a surgical intervention aimed at preventing the spread of HIV could only be justified if there were no other reasonable way to achieve this. And, even if circumcision helped to protect people in developing countries from the spread of HIV, we would not be justified in carrying this out for this purpose in developed countries, where other, better means of protection are much more readily available.”

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