The slave trade created patterns of sexual behaviour that continue to contribute to the long-term spread of HIV among young women in sub-Saharan Africa. That is one of the findings of research by Graziella Bertocchi and Arcangelo Dimico to be presented at the Royal Economic Society''s 2015 annual conference.
Their study shows that higher infection rates are associated with the health risks of polygyny, a form of plural marriage in which a man is allowed more than one wife, and the behaviours associated with it. The origins of polygyny can be traced back to the slave trade, which led to fewer men than women of marriageable age in many parts of Africa. In regions that were particularly affected by the slave trade, men are currently more likely to have more than one wife. These regions also experience comparatively higher rates of HIV infection today.
The authors analyse surveys of polygynous communities to test two ideas: first, that there are more unsatisfying marital relationships, particularly for women, who then tend to be more frequently involved in extramarital partnerships, and therefore more at risk of HIV infection; second, that when co-wives cohabit, there is a multiplying influence following this exposure for husband, wives and children.
They find that sexual activity within the previous four weeks is associated with infection rates. Female infidelity, measured as the number of extramarital partners within the last twelve months, is also strongly connected with HIV.
The results suggest that unsafe sexual behaviour arising from polygyny helps explain the higher than average prevalence of HIV among young women in Africa. The authors comment:
''Violence against women, barriers of access to services, poor education, lack of economic security, and unequal gender norms inducing unsafe sexual behaviour are the factors that are commonly suggested to explain this peculiarity.
''Our study employs new data to document the relevance of this last channel. It also uncovers how it is linked to contemporaneous family structure. Finally, it shows how much it owes to the legacy of the slave trade epoch.''
Throughout sub-Saharan Africa, polygyny is strongly associated with HIV infection rates.
The authors'' hypothesis is that polygyny is associated with unsatisfying marital relationships, particularly for the women involved. As a consequence, women tend to be more frequently involved in extramarital partnerships.
Since promiscuous sexual habits represent one of the main channels of transmission of HIV, we should then expect a statistical association between the prevalence of polygyny and the risk of infection. This effect is reinforced by co-wives'' cohabitation: the presence of several women sharing the same roof with a single husband exerts a multiplying influence on exposure, not only for husband and wives but also for children.
The above hypothesis is tested using survey-based indicators of sexual behaviour. Sexual activity, measured as the likelihood that an individual had sexual activity within the last four weeks, is confirmed as being positively associated with infection rates.
These cultural and sexual habits have deep roots in the history of the African continent. The prevalence of polygyny can in fact be related to the slave trade epoch. The slave trades, which mostly involved men, determined unbalanced sex ratios that in turn favoured the diffusion of polygyny.
By measuring the intensity of the slave trades with the decline in population it caused over the next centuries, a clear statistical link can be established between the slave trades and contemporaneous family structure: in areas affected by a larger demographic shock, men are currently more likely to have more wives. Likewise, in the same areas sexual activity and female infidelity are more intense, and HIV infection more prevalent.
HIV/AIDS is one of the most deathly diseases in Africa. What is peculiar about sub-Saharan Africa is that HIV incidence is much more common among women, especially young ones. Violence against women, barriers of access to services, poor education, lack of economic security, and unequal gender norms inducing unsafe sexual behaviour are the factors that are commonly suggested to explain this peculiarity.
This study employs new data to document the relevance of this last channel. It also uncovers how it is linked to contemporaneous family structure. Finally it shows how much it owes to the legacy of the slave trade epoch.