Pneumonia - Risk Factors

Gastroesophageal Reflux Disease. Gastroesophageal reflux disease (GERD) is a condition in which acids from the stomach move up into the esophagus. Thisaction is called reflux. Current studies indicate an association between GERD and various problems that occur in the sinuses, ears, nasal passages, and airways of the lung. People with GERD also appear to have an above-average risk for chronic bronchitis, chronic sinusitis, emphysema, pulmonary fibrosis (lung scarring), and recurrent pneumonia. If a person inhales fluid (aspirates) from the esophagus into the lungs, serious pneumonia can occur. GERD may contribute to these conditions by triggering inflammation in these upper passages.

However, GERD drugs may increase one's risk. Patients at high risk for pneumonia should take gastric acid-suppressing drugs only when necessary and at the lowest possible dose.A 2004 study found that the use of gastric acid-suppressing drugs raises the risk of developing community-acquired pneumonia. The highest risks were associated with proton pump inhibitors (PPIs) such as Prilosec and Nexium, but H2-receptor antagonists (e.g., Tagamet, Pepcid) also elevated risk. The researchers theorize thatreducing levels of germ-killing stomach acid allow germs to spread in the upper gastrointestinal tract andmove into the respiratory tract. The risk posed by these medications is highest in the elderly, children, and patients with asthma, chronic obstructive pulmonary disease,and compromised immune systems.

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Factors Associated with a Higher Risk in Healthy Adults

Dormitory or Barrack Conditions. Recruits on military bases and college students living in dormitoriesare at higher than average risk for Mycoplasma pneumonia. These groups are at lower risk, however, for more serious types of pneumonia.

Smoke and Environmental Pollutants. The risk for pneumonia in people who smoke more than a pack a day is three times that of nonsmokers. Those who are chronically exposed to secondhand cigarette smoke, which can injure airways and damage the cilia, are also at risk. Quitting smoking reduces the risk of dying from pneumonia to normal, but the full benefit takes 10 years to be realized. Toxic fumes, industrial smoke, and other air pollutants may also damage cilia function, which is a defense against bacteria in the lungs.

Drugs and Alcohol. Alcohol or drug abuse is strongly associated with pneumonia. These substances act as sedatives and can diminish the reflexes that trigger coughing and sneezing. Alcohol also interferes with the actions of macrophages, the white blood cells that destroy bacteria and other microbes. Intravenous drug abusers are at risk for pneumonia from infections that originate at the injection site and spread through the blood stream to the lungs.

Specific Risk Factors for Recurrent Pneumonia in Children

Certain children have a higher-than-normal risk for pneumonia and recurrence. Conditions that predispose infants and small children to pneumonia include:

Impaired immune system
Gastroesophageal reflux disorder
Inborn lung or heart defects
Abnormalities in muscle coordination in the mouth and throat
Asthma
Certain genetic disorders such as sickle-cell disease, cystic fibrosis, and Kartagener's syndrome, which results in malfunctioning cilia, the hair-like cells lining the airways