Pulmonary arterial hypertension, also known as PAH, is a medical condition characterized by increased blood pressure in the blood vessels transporting blood from the heart to the lungs. The blood vessels in the lungs become blocked, making it harder for blood to flow through them and increasing the blood pressure in the lungs.

The symptoms include fatigue, shortness of breath when doing regular activities, racing heartbeat, and chest pains. Some risk factors for pulmonary arterial hypertension PAH include:

1. A family history of PAH
Some cases of PAH occur when a genetic mutation that causes the disease is passed down from parents to their offspring. This type of PAH is called heritable pulmonary arterial hypertension. Around 15 to 20% of patients with PAH have heritable PAH. This high proportion is because the genetic mutation causing PAH is dominant, meaning that even if it is inherited from only one parent, the abnormal gene will cause this condition.

2. Various diseases and disorders
PAH has also been linked to various medical conditions like liver cirrhosis, connective tissue diseases, e.g., scleroderma, and lupus, rheumatoid arthritis, and other autoimmune diseases. Other conditions like congestive heart failure and lung disorders such as pulmonary fibrosis, chronic bronchitis, and emphysema have also been associated with PAH. Diseases that affect the immune system, such as autoimmune disorders and HIV, also lower the body’s immune response and make the body more susceptible to disease. Human Immunodeficiency Virus (HIV) also affects the blood vessels in the lungs, hence straining the heart.

3. Residing in high altitudes
Another form of PAH is High-altitude pulmonary hypertension, also known as HAPH. This type of PAH has been identified to affect people living in altitudes of around 2500 meters and higher. HAPH has been associated with various factors, including low oxygen concentration in the inspired air, metabolic abnormalities, and diseases affecting the blood vessels. Each of these factors could affect the lungs, forcing the heart to work harder to pump blood.

4. Exposure to asbestos and various drugs
Asbestos is a silicate mineral that has desirable characteristics such as high tensile strength, flexibility, and resistance to heat and chemicals. For this reason, asbestos was used in various products, including friction material, e.g., brake pads, concrete reinforcements like pipes and tiles, and plaster compounds. However, asbestos has been determined to cause various pulmonary diseases. Continued exposure to asbestos causes asbestosis, which can produce stiffer lungs and reduce the ability of the lungs to exchange gases. As asbestosis advances, it can lead to PAH. The use of some prescription diet drugs and illicit drugs like methamphetamine and cocaine has also been linked to PAH. This form of PAH is called drug-induced pulmonary arterial hypertension, or D-PAH. Weight loss drugs like Dexfenfluramine, Aminorex, and Benfluorex have been associated with pulmonary diseases, including PAH. Studies showed that people taking appetite-suppressant drugs for three months or more are almost nine times more likely to get PAH than non-users. Other illicit drugs that have been linked to D-PAH are amphetamines, L-tryptophan, and Dasatinib, Individuals with idiopathic PAH, where the cause of the disease is unknown, are ten times more likely to have used stimulants than patients with known causes of PAH. These drugs have been determined to affect serotonin metabolism, which has been determined as one of the causes of pulmonary arterial hypertension.