The elderly (who tend to have weakened cough and gag reflexes and unsteady immune systems) and infants and young children (who have small airways and immature immune systems) are at higher risk of community-acquired pneumonia (CAP) than are young and middle-aged adults.
Particular individuals, for example the very young, elderly, and those with chronic or severe medical conditions, are, of course, at greater risk of community-acquired pneumonia (CAP). Particularly, hospitalized patients are vulnerable to staphylococci and gram-negative bacteria, which could be very dangerous, particularly in persons who are already sick.
Patients, especially the elderly, who have recently under gone surgery or suffered a traumatic injury, are more likely to develop pneumonia since they are less able to breathe deeply, cough, and get rid of mucous.
Pneumonia is most likely to occur in people whose immune system is faltered by an existing illness, such as the influenza, AIDS, or cancer, and in patients with chronic conditions, for example, kidney disease, heart disease, sickle cell disease, asthma, chronic bronchitis, diabetes, chronic obstructive pulmonary disease (COPD), emphysema, or cystic fibrosis.
College students and recruits on military bases are at greater than average risk for Mycoplasma pneumonia, which usually is mild. However, these groups are at lower risk, for more serious types of pneumonia.
Time-to-time exposure to cigarette smoke can affect the lungs in ways that make a person more likely to develop pneumonia. The risk for pneumonia in smokers of more than one pack a day is 3 times more than nonsmokers. Those who are chronically exposed to cigarette smoke are also at risk, because it can injure airways and damage the cilia. Air pollutants such as Toxic fumes and industrial smoke may also damage cilia function, which is a defense again bacteria in the lungs.
Drug and alcohol abuse is mostly associated with pneumonia. These substances act as sedatives and therefore diminish the reflexes that trigger coughing and sneezing. Alcohol also hinders with the actions of macrophages, the white blood cells that kill bacteria and other micro-organisms. Intravenous drug abusers are highly prone to pneumonia from infections that originate at the injection place and spread through the blood stream to the lungs.