Emphysema is a form of chronic obstructive pulmonary disease (COPD). The main symptom of which is shortness of breath. In emphysema, the the small air sacs in the lungs (alveoli) are damaged, bursting to make larger sacs with a consequently smaller surface area. This reduces the efficiency of gas exchange between the blood and the lung, causing lowered blood oxygen, which in turn leads to breathlessness.
Risk Factors for Emphysema
Most people who have chronic bronchitis develop emphysema. Together, emphysema and chronic bronchitis are the most common types of chronic obstructive pulmonary disease (COPD). COPD is the fourth leading cause of death in the UK (ONS, 2018).
Emphysema is a disease where the walls between the alveoli, the fragile microscopic air sacs in the lungs where gas exchange between the lung and the blood takes place, are damaged, ruptured and broken down.
This breakdown means that the lung’s total surface area is reduced, which reduces the efficiency of the gas exchange process. This has the effect of lowering the levels of oxygen in the blood and raising the levels of carbon dioxide, causing shortness of breath.
The broken, enlarged alveolar sacs also trap old air when you exhale, meaning that there’s no room for new, inhaled air, making the breathlessness even worse as the lungs slowly enlarge.
The destroyed alveoli also deprive the bronchi (airway tubes in the lung) of support, causing them to collapse, obstructing the passage of air in and out of the lungs.
Smoking
According to Medical News Today, smoking is the number one risk factor for COPD - causing about 85-90% of COPD cases. Both tobacco and marijuana smoke can lead to extensive alveolar damage, which leads to emphysema. The mechanism by which this happens is unclear, but it might involve the inhalation of cadmium particles present in the smoke.1
Smokers are six times more likely to develop emphysema compared to non-smokers. This risk also extends to exposure to second-hand smoke.
Giving up tobacco will not reverse the disease but may slow its progression and make some treatments more effective. It may also give the immune system a boost, reducing the impact of recurrent chest infections.
Alcohol
People with alcohol dependence are three times as likely to be smokers, and smoking is very bad for patients with emphysema. However, regular alcohol consumption may also increase your risk of COPD, but the evidence is not clear cut.
Alcohol impairs the clearance of mucus and debris from the lungs by hairs (cilia) in your airways. Also, heavy alcohol consumption reduces the body’s levels of a substance called glutathione that helps to protect the lungs from damage by smoke and other irritants.
Overweight/Obesity
According to a recent editorial, more than 1 in 3 patients with COPD are obese.2 However, it has also been shown that obese patients have less frequent and severe flare-ups and are less likely to die from COPD complications than their lean counterparts. This “obesity paradox” is borne out by many studies.
Occupational/prolonged exposure to lung irritants
This includes second-hand smoke, chemical fumes, dust, and air pollution, especially ozone. These irritants cause inflammation and thereby damage the walls of the alveoli.
Gender
The prevalence and severity of emphysema are greater in people assigned male at birth than in people assigned female at birth. However, people assigned female at birth tend to experience a greater loss of lung function.
Genetics
Rarely, a genetic mutation that causes alpha-1-antitrypsin (AAT) deficiency leads to emphysema by causing a shortage of a blood protein that helps protect the elastic structure of the lungs from inflammation and damage.
Childhood history
Childhood history of lower respiratory tract infections (before the age of 2 years) are significantly associated with degraded lung function and COPD later in life.
Age
As ageing progresses, a process called cellular senescence gradually shuts down a series of mechanisms that would help to repair emphysema damage to the lungs.
Summary
Smoking, exposure to fumes, dust and pollutants, genetics, ageing, childhood respiratory tract infections, and gender are all determining factors of emphysema and COPD. In addition, there is some evidence that heavy alcohol consumption and obesity may also have the same effect, but the underlying relationships are much more complex and controversial.
References:
- Ganguly K, Levänen B, Palmberg L, Åkesson A, Lindén A. Cadmium in tobacco smokers: a neglected link to lung disease? European Respiratory Review [Internet]. 2018 [cited 2022 Mar 2]; 27(147).
- Iyer AS, Dransfield MT. The “Obesity Paradox” in Chronic Obstructive Pulmonary Disease: Can It Be Resolved? Annals ATS [Internet]. 2018 [cited 2022 Mar 2]; 15(2):158–9.
