Life expectancy for 20–year–olds initiating treatment for HIV has increased by about a decade in the European Union and North America since the introduction of antiretroviral therapy in the mid–1990s, according to a study co–authored by Yale researcher Dr. Amy Justice and published in The Lancet HIV journal. The increases are among treated individuals compared with untreated individuals, the global team of researchers said.

The study used data for 88,504 people with HIV who started antiretroviral treatment between 1996 and 2010, culled from 18 European and North American studies. To estimate life expectancy, the researchers tracked how many people died during the first three years of their treatment, their cause of death, HIV viral load, immune cell (CD4 cell) count, and whether they were infected through injecting drugs.

Fewer people who started treatment between 2008 and 2010 died during their first three years of treatment than those who started treatment between 1996 and 2007. When looking specifically at deaths due to AIDS, the researchers found that the number of deaths during treatment declined over time between 1996 and 2010, likely as a result of newer drugs being more effective in restoring the immune system.

During this time, measures of HIV improved – with the average immune cell count (of CD4 cells in the blood) increasing after a year of treatment, while the proportion of people with a low HIV viral load increased from 71% to 93%.

As a result of these improvements, between 1996 and 2013, the life expectancy of 20–year–olds treated for HIV increased by nine years for women and 10 years for men in the E.U. and North America.

The study authors propose that their findings could help reduce stigmatization and help people with HIV gain employment and obtain medical insurance, as well as encourage those diagnosed to start treatment as soon as possible and continue it fully.