Now here is an article was sufficiently interesting to raise me from my publishing lethargy and get me to WordPress. The research focuses on socioeconomic correlates of HIV in Africa. It follows from past research suggesting that wealth/poverty is not driving the epidemic, as rates are (at least initially) higher amongst well-off persons in this continent.
For her dissertation, on which this paper is based, Dr Fox (no, not that one) dug into the DHS datasets from across sub-Saharan Africa and built a mammoth of a multilevel model that allowed for individual, regional and national level income wealth and wealth inequality.
There are many interesting findings in the paper, but I wanted to highlight two. First, the headline result is that regional inequality predicts HIV infection net of personal wealth, although it is not strongly mediated by circumcision or sexual behaviour. This is of great interest to me as someone with a working interest in the impact and mechanisms of inequality on sexually transmitted diseases, although it does beg the question of what the causal mechanisms (or confounders) might be.
Perhaps more interesting, however, is found in the nuance seen when stratifying by regional wealth:
The findings also reveal a paradox that supports a dynamic interpretation of epidemic trends: in wealthier regions/countries, individuals with less wealth were more likely to be infected with HIV, whereas in poorer regions/countries, individuals with more wealth were more likely to be infected with HIV.
I read this as supporting the idea of connectivity being key to getting one into the sexual networks that put one at risk, and the idea that having resources (e.g. wealth, knowledge) once in this network is key to reducing the risk (either by leaving the network or protecting yourself within it). Note that ‘wealthier regions’ tends to mean urban, often capital.
There is a lot more work to be done on the dynamics of the relationship between socioeconomic factors and HIV infection, but this is an important step along the road.
Citation: Fox, AM. The HIV-poverty thesis re-examined: Poverty, wealth or inequality as a social determinant of HIV infection in sub-Saharan Africa? Journal of Biosocial Sciences, epub ahead of print. doi:10.1017/S0021932011000745 . Link.
I had expected this week to be quiet, what with the upcoming festive season and all, but I was pleasantly surprised to find a few titbits to look over and decide ‘yes, I should definitely read this some time soon’. Therefore, without further ado, I present:
1. A simple, yet elegant, study of the interplay of individual and national income in determining who volunteers to be tested for HIV (this paper has been around for a year or so it seems). It looks like the positive income gradient seen within countries (more income = more testing) is less pronounced in richer countries. The analysis uses individual income in within-country quintiles, which makes interpretation difficult. As the authors suggest, one way to look at things is to see this as evidence for the need to focus on poorer people in poor countries. Another angle would be to see this as evidence that there may be a positive but decreasing slope to the overall relationship internationally – i.e. there is a positive relationship up to some income threshold internationally, and then the relationship levels out. Which would suggest that focus needs to be on poor people everywhere. Either way, food for thought.
2. A recent paper on drinking and STI acquisition in the US has me thinking about the causal relationships around sex and drugs (and rock and roll) again. The paper finds various alcohol-related activities in adolescence linked to various risky behaviours (non-condom use) and self-reported STIs in early adulthood. The temporality of this relationship is clear, but the almost syndemic nature of the package of behaviours that goes with alcohol and sex – can I call it a lifestyle without implying too much or too little agency? – makes me loath to attribute any direct causal effect from the alcohol to the sex/STI. Not that the authors of this piece are claiming this, but I remain very unclear on how we might make an impact on STIs through interventions on adolescent behavioural patterns. Of course, this may just be me banging my ‘social epi’ drum, so you may wish to let me bang it in peace.
3. Here’s something from another field that interests me greatly, but I have never had the time to get into deeply enough. This is a nice conceptual effort to link human and pathogen behaviour together in an Ordinary Differential Equations setup to consider the mitigating/conflagratory effects of the former on the later in studies of dynamic disease spread. It doesn’t look too technical for the non-mathematicians amongst us, so might be worth a skim for thought-provocation, if nothing else.