I recently visited a friend in her high-rise office in New York City. She asked me to take a walk and then led me up a flight of stairs to the roof to show me the view of the Hudson River. One part of the roof had been taken over by smokers who, prohibited from lighting up inside, congregated atop the building to nurse their addictions. As we looked toward the river, I turned to see a couple of people finishing the flight of stairs to come to the roof to smoke. Both were winded and coughing but couldn’t wait to catch their breath before lighting up. My friend asked me, “Why do people cough and get out of shape from smoking?” I said they probably had the beginning stages of COPD. Of course, she then asked, “What is that?”
Chronic obstructive pulmonary disease (COPD) is caused almost exclusively by one factor—smoking. Tar and other corrosive chemicals damage the airways and small air sacs of the lungs, making it increasingly hard to get air in and out and to absorb oxygen into the body. Affecting an estimated 16 million Americans, COPD is the fourth leading cause of death in the U.S. However, because it develops slowly—COPD is diagnosed most frequently in middle-aged or older people—lung changes are often underway for many years before people notice symptoms like shortness of breath. While there is no cure for COPD, stopping smoking dramatically slows its progression, and medical treatments and lifestyle changes can reduce some of the symptoms.
WHAT IS COPD?
The lung’s airways branch out like an upside-down tree. At the end of each branch are many small, balloon-like air sacs called alveoli. In healthy people, the airways are clear and open, the alveoli are small and dainty, and all components are elastic and springy. With each breath in, the alveoli fill up with air like small balloons, and with each breath out, the balloons deflate and the air goes out. In COPD, however, the airways become swollen and the air sacs become deformed and eroded.
COPD includes two main components, chronic bronchitis, which is present in virtually all patients and is partially reversible, and emphysema, which is present in some and is irreversible.
In chronic bronchitis, the airways leading into the lungs become inflamed and thickened and the cells lining them produce excessive amounts of mucus. These changes cause a chronic cough and difficulty getting air into and out of the lungs. They also destroy specialized cells in the airways that help sweep bacteria and irritants out of the lungs. As a consequence, people with chronic bronchitis have a higher risk of lung infections.
In emphysema, the walls between many of the alveoli are destroyed, leading to a few large air sacs instead of many tiny ones. These changes dramatically reduce the lungs’ capacity to absorb oxygen and get rid of carbon dioxide. The lungs rely upon the vast surface area created by millions of alveoli to allow oxygen to enter the blood stream through tiny blood vessels in the alveoli walls. When the walls collapse, the larger air sacs that remain do not have enough surface area to absorb all the oxygen the body needs. Additionally, the walls of some of these larger air sacs become stiff and can no longer push air out of the lungs when the person exhales. Air becomes trapped in the resulting dead space, and these parts of the lung are, in effect, removed from functioning. As the lung becomes more scarred and oxygen levels fall lower, people become susceptible to severe complications like respiratory failure and heart failure.
By the time most smokers begin to notice the symptoms of COPD—like chronic cough or shortness of breath when working hard or walking fast—they have progressed already to a moderate stage of the disease. In severe COPD, people have trouble breathing after just a little activity, such as doing household chores, unloading groceries, bathing and dressing. At this stage, quality of life is greatly compromised and the worsening symptoms can be life threatening.
WHAT FACTORS INFLUENCE COPD?
Almost all cases of COPD develop after people repeatedly breathe in fumes that irritate and damage the lungs and airways. Smoking (including cigarette, pipe and cigar smoking) is by far the most common cause, responsible for 85 to 90 percent of all cases. While only 15 to 20 percent of smokers are formally diagnosed with COPD, this commonly cited statistic is now known to be a gross underestimate of the number of people affected. Some recent data suggest that 70 to 90 percent of smokers develop COPD during their lifetimes, and 20 percent develop it rapidly. Occupational exposure over prolonged periods to dust, certain chemical fumes and gases can also contribute in some cases.
There is controversy over the role that exposure to heavy air pollution and second-hand smoke plays in COPD. Several studies show that these factors worsen other respiratory illnesses such as asthma, increase the risk for symptoms such as wheezing and coughing, and make the airways more sensitive to irritants. Nevertheless, current studies have yet to conclusively link them to the more severe changes of COPD. For example, one of the largest studies to date of second-hand smoke showed no increase for spouses of smokers in deaths from COPD, heart disease or lung cancer—the three most significant killers of smokers—as long as the spouses had never smoked themselves. It remains largely unclear why some smokers develop COPD and others do not, but some evidence points to the role of genetics. Smokers whose parents had COPD are more likely to develop COPD themselves. In rare cases, COPD is caused by genetics even when smoking is not involved: Alpha 1 antitrypsin deficiency, or familial emphysema, is caused by the hereditary deficiency of a protein needed to inactivate destructive enzymes in the blood. This imbalance leads to the destruction of the lung and COPD. If people with this condition smoke, the disease progresses more rapidly.
HOW IS COPD DIAGNOSED?
COPD is often misdiagnosed as a respiratory infection or asthma because symptoms can be similar, although the distinction can be made with a careful history, physical exam and breathing tests. Doctors should consider a diagnosis of COPD when a patient has the typical symptoms and a history of exposure to lung irritants, especially cigarette smoke.
A quick, painless breathing test called spirometry can detect COPD long before a person has significant symptoms. Patients breathe hard into a large hose connected to a machine called a spirometer, which measures how much air their lungs can hold and how fast they can blow the air out after taking a deep breath. Additional tests may be performed to help determine the stage of COPD and to evaluate for other illnesses, such as heart failure, that can cause shortness of breath.
HOW IS COPD TREATED?
Quitting smoking is the single most important thing a person can do to reduce the risk of developing COPD and to prevent it from becoming worse.
Medical interventions for COPD can help relieve some of the symptoms, but COPD cannot be cured. The goals of treatment are to improve breathing, slow the progression of the disease, increase the ability to stay active, prevent and treat complications and improve overall health. Depending on the severity of illness, some patients may be referred to a lung specialist called a pulmonologist.
The primary COPD medications, called bronchodilators, work by relaxing the muscles around the airways so they open more quickly and breathing is easier. Most bronchodilator medications are inhaled. Because there are many kinds of inhalers, it is important for patients to know how to use theirs correctly, and they should ask the doctor or pharmacist to observe them administering a dose. Other medications sometimes used include corticosteroids, which reduce airway inflammation, and mucolytics, which break down mucus and make it easier to clear from the lungs.
Because lung function is already reduced in people with COPD, infections like influenza or pneumonia can be devastating. Therefore, yearly flu vaccinations and the one-time vaccination against pneumococcal pneumonia are very important.
Another mainstay of COPD treatment is pulmonary rehabilitation, where many different health care professionals work together to help people with COPD stay more active and have less difficulty carrying out their day-to-day activities. Programs include exercise, education in disease management, breathing retraining, nutritional counseling and psychosocial support. Respiratory therapists teach pursed-lip breathing, which helps relieve some of the fatigue people with COPD develop from breathing rapidly and shallowly. Occupational therapists teach ways of doing daily activities so as to conserve energy and lessen exertion.
For people with severe COPD and very low levels of oxygen in the blood, doctors may recommend oxygen therapy. In these cases, using extra oxygen can help people do activities with less shortness of breath, help protect the heart and other organs from damage and even prolong life.
In a small number of cases, surgery may be recommended for people who have severe symptoms, have never gotten improvement from medications and have a very hard time breathing most of the time. Surgery may remove an unusually large air sac that compresses healthy lung tissue, or it may involve complete lung transplant.
HOW DOES ONE STOP SMOKING?
COPD has been thought of as a disease of the elderly, but in recent decades the decline in the average age at which people begin smoking (now age 10) means that someone who smokes a pack a day could reach, by age 30, the average exposure sufficient to produce symptomatic COPD. When the toll from COPD is added to the toll from other illnesses caused by smoking—such as heart disease, stroke and cancer—tobacco-related illnesses account for 20 percent of all deaths in the U.S. That means that the single most important step a person can take to maintain health and prolong life is to stop smoking.
Nicotine withdrawal symptoms such as depression, insomnia, irritability, anxiety and poor concentration are the main deterrents to quitting for most people. Studies show that more than 60 percent of people who smoke report that they intend to quit within the next 6 months, yet each year only 3 to 5 percent of those who attempt to stop will achieve a sustained quit (greater than 12 months). It is estimated that people who smoke need an average of four attempts to quit before they are able to maintain sustained cessation.
Chances for quitting successfully can be improved with the use of medications and behavioral therapy. The standard approach to drug therapy for smoking cessation has been nicotine replacement systems—including patches, gum, inhalers and nasal sprays—which help smokers withdraw gradually from nicotine. While some people avoid nicotine replacement because they don’t see the advantage of switching to another product that is still addictive, it is important to recognize that nicotine replacement is infinitely safer than smoking. While nicotine is the substance responsible for the addiction, tar and many other chemicals in tobacco cause the lung damage and other health problems. Using nicotine replacement is estimated to double a smoker’s chances of quitting successfully. The antidepressant buproprion (marketed as Zyban or Wellbutrin) has also been shown to reduce withdrawal symptoms and can be used alone or in combination with nicotine replacement.
Medications work far better when combined with behavioral therapy, although few smokers take advantage of the available programs. Behavioral therapy helps people identify barriers to quitting and plan to prevent relapses. An average of 20 percent of people who participate in a behavioral therapy program are able to maintain sustained cessation, a significantly greater success rate than in smokers who try to quit without support.
It is difficult to stop smoking, but it can be done. For those folks smoking on the rooftop who want to quit, I hope you keep trying.
by Gillian Friedman, MD
National Heart, Lung, and Blood Institute www.nhlbi.nih.gov
The Foundation for a Smoke-Free America www.anti-smoking.org
National Cancer Institute’s Smoking Quitline 877.44U.QUIT