You’ve heard of post-traumatic stress disorder (PTSD), but U.S. veterans are often plagued with health issues that go unnoticed by the general public. As we celebrate their service on Veterans Day, it’s important that we give respect to the men and women who’ve served, by recognizing the long-term effects that many still deal with years after they’ve left the armed forces.

When veterans come home from service, they often bring the effects of their time away with them. Unfortunately, these effects can cause significant damage for years to come.

1. Gulf War Syndrome

Gulf War Syndrome is a collection of potentially debilitating symptoms that plague some veterans of the 1991 Gulf War. They include chronic fatigue, fibromyalgia, muscle and joint pain, headaches, psychological problems, forgetfulness, and gastrointestinal disorders.

Some estimates say that it affects 30 percent of the men and women who served during the conflict. While the exact cause remains unknown, the same study found that veterans who experience these symptoms also experienced a loss of brain matter.

The Veterans Administration (VA) doesn’t like the term Gulf War Syndrome, preferring to categorize the condition as “chronic multisymptom illness,” or sometimes simply as “undiagnosed illnesses.”

2. Autoimmune Diseases

PTSD is a potential risk for all veterans, but has proven particularly common among those who fought in Iraq and Afghanistan. And one alarming finding to come out of research on the disorder is that it could be putting veterans at a greater risk of autoimmune diseases.

Researchers in California have found that post-traumatic stress can trigger biological changes and alter the functioning of the immune system, together contributing to disease. As a result, veterans with PTSD are more likely to be diagnosed with rheumatoid arthritis, multiple sclerosis, lupus, and inflammatory bowel disease.

3. Effects of Jet Fuel Exposure

As many as 2 million workers worldwide are regularly exposed to jet fuel, at least some of them U.S. military personnel. According to research from Boston University, the effects of exposure to jet fuel — both by inhalation and absorption through the skin — remain largely unknown, but it’s believed that they include long-term neurological effects.

This damage to the brain could be causing hearing problems, according to the VA. While veterans with exposure may be able to hear a sound, their brain could be unable to decipher it. These problems were commonly attributed to exposure to loud noise, but researchers now say jet fuel itself could play a role.

4. Other Forms of Hearing Loss

Though there may be a connection between jet fuel exposure and hearing problems, hearing loss due to prolonged exposure to high volumes of sound is also a concern. In fact, it's the most common veteran injury. Among new recipients of veteran’s disability benefits in 2003, some 75,000 cases were attributed to hearing loss, according to the Institute of Medicine.

5. Diabetes

Diabetes is a national problem, but the risk of developing type 2 diabetes might be higher for some veterans. According to the VA, close to 25 percent of veterans of the Vietnam War have type 2 diabetes, which is over double the incidence of both forms of diabetes in the United States. And it could be tied to Agent Orange exposure.

The reason exposure to this chemical weapon increases diabetes risk is unknown, but in admittance of the connection, the VA covers diabetes care for veterans who were exposed and later developed the disease.

6. Lung Problems

Service members deployed to dusty and sandy regions — particularly those involved in the Persian Gulf, Iraq, and Afghanistan military operations — may come home with respiratory problems. A Pentagon-funded study found that 14 percent of Iraq war veterans experience chronic respiratory problems, compared with 10 percent of those not deployed to Iraq. Some of this damage is likely due to sand and dust, but another source is burn pits commonly used to destroy waste during the most recent military operations.

7. Effects of Depleted Uranium

A product of “friendly fire” or exposure to the U.S. military’s own weapons, depleted uranium is one of the more controversial health concerns facing veterans.

Depleted uranium (DU) was first used in U.S. military weaponry in 1991. It is a byproduct of nuclear fuel production, and is said to be 40 percent less radioactive than natural uranium. DU is used in bullets to penetrate armored vehicles. When these bullets hit their target, DU particles can scatter into wounds and soft tissue, and into the air where it is breathed.

So, what are the health effects of DU exposure? The VA is vague on the topic, and research is limited. According to the World Health Organization, the main areas of concern are kidney and lung damage, though even they admit there are “gaps” in knowledge about the effects of exposure.

The State of Veteran Health

It’s a common misconception that all veterans are entitled to free healthcare even after they leave the armed forces. Only those who qualify due to low income or proven disability are entitled to such benefits. As a matter of fact, a 2014 study found that more than 1.2 million veterans lack health insurance altogether.

Over the past few years, the VA’s health system has been in turmoil with accusations of poor treatment, long wait times, and falsified records. When looked at through the lens of the many health problems awaiting veterans when they come home from overseas or leave the military, these problems are even more difficult to stomach.

On Veterans Day, as we celebrate those men and women who have put their lives on the line for their country, it’s important we acknowledge that many of them are still living with their sacrifices to this day.