Pneumonia | Causes & Risk Factors


Who is at risk of developing pneumonia?

You are more at risk of developing pneumonia if:

You are older than 65 years of age. As you get older, your immune system becomes less able to fight off infections like pneumonia. Babies and young children are also at increased risk because their immune systems are not yet fully developed.

You have a disease or condition that weakens your immune system. When your immune system is weakened, it’s easier for you to get pneumonia because your body can’t fight off the infection. People who have weakened immune systems are also more likely to develop pneumonia from bacteria, viruses and germs that don’t cause pneumonia in healthy people.

People who have any of the following are at increased risk:

  • Chronic obstructive pulmonary disease (COPD), especially if you have taken inhaled corticosteroids for 24 weeks or longer
  • Human immunodeficiency virus (HIV)
  • Acquired immunodeficiency syndrome (AIDS)
  • Heart disease
  • Emphysema
  • Diabetes

People who have recently had an organ transplant and people who are receiving chemotherapy are also at increased risk.

You work in construction or agriculture. Working in environments where you breathe in dust, chemicals, air pollution or toxic fumes can damage your lungs and make them more vulnerable to infections like pneumonia.

You smoke or abuse alcohol. Smoking damages the tiny hairs in the lungs that help remove germs and bacteria. Alcohol abuse can put you at increased risk of aspiration pneumonia, a type of pneumonia that develops after you inhale particles into your lungs. This occurs most often when you vomit and small particles enter your lungs because you are not strong enough to cough the particles out. Alcohol abuse also interferes with the way your white blood cells (which are responsible for fighting infection) work.

You are hospitalized, especially in an intensive care unit (ICU). Pneumonia that you catch in a hospital (called hospital-acquired pneumonia) can be more serious than other types of pneumonia. Your risk increases if you are using a ventilator to help you breathe. Ventilators make it hard for you to cough and can trap germs that cause infection in your lungs.

You have recently had major surgery or a serious injury. Recovering from major surgery or a serious injury often makes you weak. It can also make it difficult for you to cough, which is the body’s quickest defense for getting particles out of the lungs. Recovery also typically requires a lot of bed rest. Lying down on your back for an extended period of time can allow fluid or mucus to gather in your lungs, giving bacteria a place to grow.

You are of Native Alaskan or Native American descent. For reasons unknown to doctors, people of these ethnic groups are at increased risk for pneumonia.

Written by editorial staff

Reviewed/Updated: 04/14
Created: 03/09