Smoking could potentially shorten the lifespan of people living with HIV more than the virus itself, suggests new research.

Using a computer simulation, researchers estimated that Americans infected with HIV could lose more than six years off their life as a result of smoking, unrelated to their infection.

This was compared to a similar group of people with HIV who don’t smoke.

While only 17 percent of the general American adult population smokes cigarettes, the rate is much higher among people with HIV — 42 percent in 2009.

Quitting smoking — especially at an earlier age — could reduce the increased risk of lung cancer, heart disease, and other smoking-related illnesses.

"Smoking cessation should be a key part of the care of people living with HIV to improve both their lifespan and their quality of life," study co-author Dr. Travis Baggett, a clinician and researcher at the Massachusetts General Hospital Division of General Internal Medicine and the Tobacco Research and Treatment Center, said in a press release.

The results were published online Nov. 3 in the Journal of Infectious Diseases.

Read more: Why HIV patients must stop smoking »

Living longer with HIV

Better treatment options in recent years — including newer antiretroviral medications — have changed the long-term outlook for people with HIV.

“The great news is that they basically have a life expectancy that’s very similar to people without HIV,” Jane Simoni, Ph.D., a professor of Psychology at the University of Washington, told Healthline.

According to a study published earlier this year, in 2011 the life expectancy of people with HIV was 73 years.

That’s still about 12 years behind the general population.

But it’s a large jump from 1997, when HIV patients could expect to live 39 years on average.

It means that people with HIV are living long enough to develop heart disease, cancer, and other conditions — sometimes at higher rates than the general population.

“As more people with HIV are living into their 60s and 70s, we are of course seeing a combination of health conditions that may reflect residual damage from HIV or its treatment versus those we normally expect to see in an aging population,” Dr. Paul Volberding, the director of the AIDS Research Institute at the University of California, San Francisco, told Healthline in an email.

There is a lot of research interest in this area. Many factors likely play a role in increasing the risk of other diseases.

“It turns out it’s not all that easy to dissect these issues,” said Volberding.

HIV may change how quickly diseases like cancer or heart disease progress or how they affect people.

Treatments for HIV have also changed over the years, which could impact life expectancy.

“Those starting HIV treatment earlier in the disease course with the less toxic drugs we now have may fare better than the earlier cohort, where late disease presentation was common and the dogma was to wait until disease had progressed,” Volberding added.

Read more: Life expectancy for people with HIV improves »

Long-term mental health with HIV

Just as smoking can increase the risk of lung disease in people with HIV, other lifestyle and background factors may also affect their health.

This is especially true for mental health issues.

By itself, being diagnosed with HIV can lead to stress, anxiety, or depression, especially early on — what Simoni calls “diagnosis distress.”

Better medications and longer lifespans for people with HIV, though, have dissipated some of the concern over dying early or becoming sick.

However, without a cure for HIV, people still need to deal with the stress of having a lifelong condition.

“The long-term burden of having a chronic illness and having to think about it all the time can be wearing on people,” said Simoni.

HIV can also draw harsh judgments or discrimination from others, whether in the workplace or among social circles, which can affect a person’s mental health.

Some people with a higher risk of HIV infection may also develop mental health problems as a result of stigma and feeling marginalized.

High-risk groups include men who have sex with men, people who are transgender, and people of certain racial backgrounds and ethnic minorities.

HIV infection is also more common in lower income groups and among people who use intravenous drugs.

Some of these people may lack regular access to healthcare — which includes mental healthcare.

“All those issues put them at risk for mental health distress,” said Simoni, “but not specifically as much from HIV anymore.”

Earlier access to mental health treatments could improve the quality of life for people with HIV, just as earlier smoking cessation programs can improve lung health.

Simoni said some health centers try to integrate mental healthcare into HIV primary care, with social workers, psychiatrists, and other mental health workers available for patients.

Another way to improve the mental health of people with HIV is by talking more openly.

“One of the interventions needs to be community-wide, public health campaigns destigmatizing mental illness and HIV,” said Simoni. “That will go a long way to improving the mental health for people with HIV.”

Read more: People with HIV suffer from depression »