Monday, March 9, 2009

Facts that do not Speak for Themselves

It's very tempting to blame the spread of a sexually transmitted infection (STI) such as HIV on promiscuity. It would be useful to have a criterion for 'promiscuity' as opposed to reasonably normal levels of sexual activity, of course. But the fact is that there is no evidence that Africans, as opposed to people from other continents, are more promiscuous. The evidence suggests that in Africa, as in other continents, some people have a lot of sex and some don't.

It would be very easy to dismiss the last paragraph on the grounds that so many articles state or imply that Africans are more promiscuous than the rest of the world. However, I have yet to come across any evidence for the belief, unless the constant reassertion of something counts as evidence. We don't need an explicit definition of promiscuity, we understand what it means. It's just that the term is being applied indiscriminately.

An interesting study of sexual behaviour was carried out in four African countries with very different rates of HIV; Benin and Cameroon, which both have low HIV prevalence and Kenya and Zambia, which both have high prevalence. The highest rates of partner change were found in Cameroon, especially among men. Even among women, partner change was higher in Cameroon.

In Kenya and Zambia, the age of sexual initiation was slightly lower. There were also lower rates of circumcision and higher rates of other STIs, such as herpes simplex virus (HSV). But there was simply no correlation between HIV prevalence and indicators of sexual behaviour, such as concurrent sexual partners.

Another study found that there were more people in African countries than in countries in other continents who reported having had no sex in the month preceding the survey. And most men in all countries surveyed had no extramarital sex or no sex outside of a long term relationship. Overall, the views of Africans surveyed were more enlightened than the views of those from other continents.

Yet another survey found that age of sexual initiation for females was increasing in most countries surveyed in Africa between the 1960s and the 1990s. But it's interesting to compare age of sexual initiation in developed and developing countries. The country with the highest percentage of 15-19 year olds who are not married and have already had sexual intercourse is the UK, and this stands for both males and females. Also high on the list are Brazil, the US and the Dominican Republic. All these countries have low HIV prevalence, less than 1% in the UK, the US and Brazil.

When it comes to lack of knowledge about sex, contraception and safe sex, levels of unwanted and teenage pregnancies and other matters, the US and the UK are usually very high on the list. It is interesting that these two countries have so many worrying indicators, yet they both have relatively low HIV prevalence.

And so on. Eileen Stillwaggon in AIDS and the Ecology of Poverty lists a number of studies that show that the evidence does not bear out the assumptions about HIV transmission being explained wholly by sexual behaviour. In every country, people have sex. In every country some people have more sex than others. But there is no country where HIV rates can be correlated with high levels of unsafe sexual behaviour, partner change, concurrent relationships and the rest.

This is not to say that there is not a lot of evidence of unsafe sex in developing countries. There is a lot of unsafe sex taking place all over the world. But not all countries have high HIV prevalence. That is the question that researchers have been trying to find the answer to for so many years. It hasn't escaped their notice that STIs are spread by people having sex. They are asking why there are extremely high levels of HIV transmission in some countries and low levels in other countries.

Some have suggested that poverty is a key factor in the spread of HIV. Indeed, people probably don't engage in commercial sex work when they have money coming in from other activities. So poverty must play a part. Others have gone on to show that poverty alone doesn't explain HIV prevalence rates because some poor countries don't have high rates of HIV. One response to this is that economic inequality may be a better way of looking at wealth and poverty, some people are dependent and others have the opportunity to buy sex as and when they want it, they can afford concurrent partnerships.

There are many counter examples to poverty and even inequality driving HIV epidemics and it has been clear for a long time that HIV has many drivers. It is futile to expect to find one factor that drives all epidemics and pointless to argue that poverty or inequality or whatever have no part to play. Epidemics involve many different people with different lives and circumstances interacting with each other.

This blog already covered Senegal
, where education, health and other social indicators are probably not that different from those in Kenya, certainly not different enough to explain the low levels of HIV in Senegal. The histories of HIV transmission are many and various, between and within different countries.

A recent literature review listed the top factors contributing to HIV transmission as: "poverty, famine, low status of women in society, corruption, naive risk taking perception, resistance to sexual behaviour change, high prevalence of sexually transmitted infections (STI), internal conflicts and refugee status, antiquated beliefs, lack of recreational facilities, ignorance of individual's HIV status, child and adult prostitution, uncertainty of safety of blood intended for transfusion, widow inheritance, circumcision, illiteracy and female genital cutting and polygamy."

The article also finds these factors to be "interrelated and complementary". There is no one factor that is the most significant. Even poverty, which is by far the most significant, is closely related to many of the other factors. For example, people who are poor are also more likely to have lower levels of heath and therefore be more susceptible to HIV. They have worse living conditions, they have fewer opportunities, less education, they are more vulnerable to the effects of corruption, crime, global financial crises, food prices and global environmental degradation, and the list goes on.

The issue of connections between poverty and HIV transmission keeps coming up, as if examples of HIV transmission that are not related to poverty suggest that poverty is not a problem. Even if HIV were to disappear tomorrow, poverty is a problem. Poverty needs to be eradicated because it denies people many of their human rights. But also, in countries where wealthy people are more likely to be HIV positive, poverty is not in any way less relevant.

If there are some people who can afford to pay to have wide sexual networks and there are some people who need to be part of a sexual network because they are poor, then 'poverty' doesn't describe the problem. The level of economic inequality more accurately describes it. And before anyone starts throwing counterexamples at me, this is not to say that there are not many other factors involved. The very point is that there are many factors in the transmission of HIV. Poverty and inequality are important but they relate to numerous areas of underdevelopment that are also important factors.

It has been recognised for some time that in Kenya and Tanzania, for example, HIV prevalence is higher in wealthier quintiles. Clearly, there are different circumstances surrounding each instance of HIV transmission. But the problem is to explain what circumstances give rise to, say, the fact that women in the wealthiest quintile in Tanzania have four times the level of HIV positive people than the poorest quintile.

If your causal story is that rich men pay to have sex with poor women, would you add to this that rich women are even more likely to pay to have sex with poor men? I'm not saying that this never happens but I have seen no evidence that this is common. I don't know where all these transactions could take place because I haven't seen young men in bars looking for rich women. There are many young men in bars looking for women to have sex with but they tend to target foreigners, so this doesn't explain the level of HIV among wealthy Tanzanian women.

There is clearly a lot about HIV transmission that we don't yet know. I took a quick look at the occupations of women who are in the wealthiest quintile and was surprised to find that 10% say they do subsistence work and 25% say they do stall and market work. The highest percentage say they have no occupation. Those in the wealthiest quintile may well be dependent on their husbands, but this does not explain why the correlation between wealth and HIV prevalence is stronger for women than for men.

There is more to wealth than occupation and those surveyed are also asked about property, household income as a whole, amenities, etc. But it is remarkable that more than 75% of women in the bottom three quintiles give their occupation as subsistence work. Even in the second wealthiest quintile, more than 50% list their occupation as subsistence work. The bottom three quintiles have a lot in common on the basis of occupation type, the top quintile is quite different. No doubt, these differences in occupation type are related to many other differences in factors that relate to HIV transmission.

But this is only speculation, there is too little data available and it is not finely grained enough to work out or evaluate all the important drivers of HIV epidemics. There are many factors and therefore there are many facts. But the ‘facts’ often appear counterintuitive and there are probably many that we, as yet, know nothing about. What is clear is that a lot of interpretation and clarification is needed and that the facts do not in any sense speak for themselves.


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