Life expectancy of people with HIV in Europe and the US has increased by 10 years, a new study has suggested.

The dramatic increase - which reflects 20-year-olds starting treatment for HIV - is being attributed to the introduction of antiretroviral therapy in the mid-1990s.

Antiretroviral therapy sees patients taking several types of medicine that aim to slow the rate at which the virus copies itself.

A study looked at almost two-decades of data from more than 88,000 people with HIV, and the findings have been published in The Lancet journal.

As a result of the therapy and other improvements in treatment, life expectancy for 20-year-olds treated for HIV after 1996 increased by nine years for women and 10 years for men.

Researchers say that the life expectancy of young patients who began treatment from 2008 onwards "may approach that of the general population" - but "further efforts" are required to achieve that.

Lead author Adam Trickey - from the University of Bristol - observed: "Our research illustrates a success story of how improved HIV treatments coupled with screening, prevention and treatment of health problems associated with HIV infection can extend the lifespan of people diagnosed with HIV.

"Combination antiretroviral therapy has been used to treat HIV for 20 years, but newer drugs have fewer side effects, involve taking fewer pills, better prevent replication of the virus and are more difficult for the virus to become resistant to."

He added: "Since modern treatment is highly effective with low toxicity, deaths in people living with HIV are unlikely to be reduced by further development of drugs. Now we need to focus on the issues surrounding drug adherence, late diagnosis of HIV, and diagnosis and treatment of co-occurring conditions."