Longer secondary education protects against HIV infection

Longer secondary schooling substantially reduces the risk of contracting HIV, particularly for girls, according to a new study conducted in Botswana.
The researchers found that pupils in Botswana who stayed in school for an extra year of secondary school had an 8 percentage point lower risk of HIV infection a decade later, from about 25 per cent to about 17 per cent infected.
The study used a recent school policy reform in Botswana as a 'natural experiment' to determine the impact of increased years of secondary schooling on risk of HIV infection.
Implemented in 1996, the reform led to an average increase of 0.8 years of schooling among teenagers, by providing free grade 10 education as part of junior - rather than senior - secondary school.

This policy presented a unique opportunity to estimate the causal effect of length of schooling on risk of HIV infection by comparing birth cohorts exposed to the reform versus those unexposed, using data from national HIV surveys collected in 2004 and 2008.
Education is known to be closely associated with health, but whether or not formal education actually protects against HIV infection has been hotly debated for over two decades.

Using data from two nationally representative household surveys, the Botswana AIDS Impact Surveys (2004 and 2008), the researchers used statistical techniques used in economics and political science to analyse natural experiments.

Botswana has one of the highest rates of HIV in the world, with around 22 per cent of adults aged 15-49 years infected in 2013.
The study published in The Lancet Global Health journal investigated the causal effect of an additional year of schooling on HIV status in 7,018 men and women at least 18 years old at the time of the surveys.
Individuals born in or after 1981 (who would have started junior secondary school in 1996 or later) were classified as exposed to the reform.
The researchers estimated that individuals who gained an extra year of secondary schooling due to the policy were 8 percentage points less likely to test positive for HIV about a decade later, when most of those exposed to the policy were in their mid 20s.

The effects were particularly strong among women, with each additional year of secondary schooling reducing infection risk by 12 percentage points.
"Information about prevention methods and reasoning skills gained in school may play a preventative role against HIV, enabling people with education to adopt healthy strategies to avoid infection," said co-author Jan-Walter de Neve, a doctoral student at Harvard TH Chan School of Public Health, Boston.
"Additionally, education may expand economic opportunities and reduce women's participation in higher risk transactional sexual relationships.
"Secondary schooling may be particularly effective in reducing HIV risk by targeting a critical period of growth in adolescence," Neve said.