What Are the Risk Factors for COPD?

Chronic obstructive pulmonary disease affects older people more than younger people. The Mayo Clinic reports that most people are 40 or older when they're first diagnosed with COPD. As a cumulative, degenerative disease, COPD usually requires many years of exposure to certain triggers. And the more of these triggers you come into contact with regularly, the higher your risk of developing COPD.

Philip Diaz, a pulmonary specialist at The Ohio State University Wexner Medical Center in Columbus, Ohio, says there are several risk factors that can contribute to developing COPD, but "smoking is the big one. It's uncommon to see someone with significant disease who doesn't have a history of smoking."

Smokers routinely draw a vast number of potential irritants into their lungs, and this frequent exposure can result in severe damage to the lungs that progresses into COPD. The National Heart, Lung, and Blood Institute reports that "smoking is the most common cause of COPD, accounting for as many as 9 out of 10 COPD-related deaths." More than 120,000 people in the U.S. die of COPD each year.

[See: 16 Ways Your Body Adjusts to a New Climate.]

Although smoking is the primary driver of chronic obstructive pulmonary disease diagnoses, virtually any inhaled irritant can create damage in the lungs that can build up over time to create the right conditions for developing COPD. "Occupational dust can be a risk factor," Diaz says. "People who've worked in coal mines or have come into contact with silica dust" can be at risk, too.

Exposure to inhaled substances that can damage your lungs can happen outside of work, too. For example, Diaz says he had "a population of injected drug use patients who had chronic obstructive pulmonary disease. I don't know how common it is now, but they would grind up pills, dilute the dust with liquid and inject it. The talc that's used as a filler in the pills would become airborne and lodge in the lungs and destroy the lungs. They developed emphysema," which led to COPD, he says.

Toxins and pollutants in the air and secondhand smoke are also thought to contribute to the development of COPD, but neither has been proven to be as big a risk factor as smoking. Studies seeking a direct link between air pollution and the development of COPD are still inconclusive, but air pollution has been linked with exacerbations of COPD, or a severe worsening of symptoms that sometimes require hospitalization.

Diaz says COPD also seems to be connected with "significant childhood respiratory infections," and issues with lung growth and development among children. Because the lungs continue to develop throughout childhood, babies born too early may not have as well developed a respiratory system as full-term babies; these issues can potentially have health implications later in life. Similarly, several studies have made a clear connection between childhood asthma and the development of COPD later in life. "Most people with asthma don't develop COPD," Diaz says, but some do. A 2016 study published in the New England Journal of Medicine offered substantial evidence in support of the connection between childhood lung issues and COPD later in life.

Other risk factors that tend to be more prevalent in less industrialized countries include indoor pollution from bio-mass cooking and heating -- home heating or food cooking stoves that use animal dung or wood as their primary fuel source. HIV infection is also a risk factor for developing COPD.

Body weight may also play a small role in COPD risk. "Weight is a really interesting thing," says Diaz. "You see people with advanced COPD develop malnutrition and weight loss, which is a marker for poor prognosis. And there's some data in good longitudinal studies that smokers with low BMIs are more likely to develop COPD." The body mass index is a measure that incorporates height and weight. Diaz says he thinks there's a connection between low body weight and the body's ability to repair itself, but it's just a hypothesis for now. "Certain mechanisms with tissue repair may not be as intact with people with low nutrition."

Regardless of the underlying cause for the connection between weight and chronic obstructive pulmonary disease, Diaz says "when you do develop COPD, your prognosis is better when you're heavier. I'm not advocating that people become obese," he adds, but "being underweight is more of a risk."

[See: 7 Things You Didn't Know About Lung Cancer.]

Although COPD predominantly affects older people, younger people can develop it too, and in many of these cases, genetics are to blame. Some people have a genetic deficiency in a particular protein that's involved in the repair of the lungs called alpha-1 antitrypsin. The Respiratory Health Association, a lung health advocacy group based in Chicago, reports that "alpha-1 antitrypsin is a protein that helps protect lungs against damage from toxins. When the body releases white blood cells to fight off infection or disease, the liver releases AAT to protect against damaging enzymes. For someone who has an AAT deficiency, the body does not release any or enough AAT, so the person can develop lung damage (emphysema)."

"If you have that deficiency, you can develop accelerated emphysema," Diaz says, which can become COPD. The specifics of what's going on with this protein deficiency haven't been completely worked out, Diaz says, but it seems clear that there's a genetic component to the development of COPD, especially among younger patients.

Lastly, your sex may also be a contributing factor to developing chronic obstructive pulmonary disease. "If you get severe, early onset COPD -- that's defined by getting the disease at age 50 or younger -- you're much more likely to be a woman. We don't understand why that is," Diaz says, but there's a theory that because women have on average smaller lungs and body types as compared to most men, when they smoke, they're taking in a relatively higher proportion of irritants into their lungs that can trigger COPD.

If you're concerned about your lung health and think you might be at risk for developing COPD, Diaz says there is one main thing you can do to reduce your risk: "Don't smoke. That's far and away the biggest thing. A lot of those other risk factors are often observed in conjunction with cigarette smoking," so while you have no control over having been born prematurely, if you stop smoking now, your risk of developing chronic obstructive pulmonary disease will go down.

[See: 7 Lifestyle Tips to Manage Your Asthma.]

Diaz also advises patients to "be sensible about certain things with regard to working around a lot of dust and pollution. Again, those things don't usually independently cause significant disease." Nevertheless, if you're working around dust or other airborne particles, wear a mask to keep from breathing in those substances.

And of course, just generally taking care of yourself, eating right, exercising and getting enough rest is sensible advice that may help you avoid various kinds of illness in the future. But Diaz says "the bottom line is don't smoke. That's the biggest message."

Elaine K. Howley is a freelance Health reporter at U.S. News. An award-winning writer specializing in health, fitness, sports and history, her work has appeared in numerous print and online publications, including AARP.org, espnW, SWIMMER magazine and Atlas Obscura. She's also a world-record holding marathon swimmer with a passion for animals and beer. Contact her via her website: elainekhowley.com.