Chronic obstructive pulmonary disease, or COPD, is one of the world’s leading causes of death, responsible for 3.5 million deaths in 2021 alone. It is often thought of as a disease of older smokers. But that picture is too simple. COPD usually develops slowly over many years, often long before symptoms become obvious.
COPD is a long-term lung condition that makes it harder to move air in and out of the lungs. It includes damage to the airways, often described as chronic bronchitis, and destruction of the tiny air sacs in the lungs, known as emphysema. Because this damage builds up gradually, many people do not realise anything is wrong until symptoms become difficult to ignore. There are treatments that can help, but there is no cure, and by the time COPD is diagnosed the damage is often permanent.
Common symptoms include a long-term cough, bringing up mucus and shortness of breath. These symptoms often appear later in life, which helps explain why COPD is so often seen as an older person’s disease. But in many cases, the damage started decades earlier.
Many environmental irritants can harm the lungs, but cigarette smoke remains the main cause of COPD. Cigarette smoke contains thousands of chemicals, including toxic gases and cancer-causing substances, that injure lung tissue and trigger oxidative stress, a form of cellular damage that drives inflammation.
Inflammation is part of the body’s normal defence and repair system. Usually, it settles once the source of harm has gone. But in COPD, the lungs may be exposed to cigarette smoke day after day, so the inflammatory response never properly switches off.
Over time, immune cells sent to repair the damage can end up injuring the lungs further. The airways become narrower, the lungs produce more mucus, and the tiny air sacs known as alveoli can break down. Together, these changes make breathing increasingly difficult.
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As the disease progresses, the lungs are physically altered in ways that cannot be fully reversed, even if someone stops smoking. COPD inflammation also does not always respond well to standard anti-inflammatory medicines such as steroids, which is one reason prevention matters so much.
Although cigarette smoking remains the main driver of COPD, e-cigarettes are also raising concerns. Vaping aerosols can contain nicotine, ultrafine particles and flavouring chemicals that may irritate the lungs and contribute to inflammation. The long-term effects are still unclear because these products are relatively new.
That matters particularly for younger people. In Great Britain, recent survey data suggest that 7% of 11- to 17-year-olds currently vape. While that does not mean they will go on to develop COPD, it does mean more young lungs are being exposed to substances whose long-term effects are not yet fully understood.
COPD is often diagnosed only after major lung damage has already occurred. Because it develops so gradually, people may dismiss early breathlessness, coughing or mucus production as a consequence of getting older, being unfit or smoking. Respiratory organisations warn that symptoms such as cough, phlegm and shortness of breath should not be treated as a normal part of ageing, while studies show that COPD remains widely underdiagnosed, including among people with respiratory symptoms.
The burden on health systems is huge. A 2023 study estimated that COPD could cost the global economy around INT$4.3 trillion between 2020 and 2050. International dollars adjust for differences in prices between countries; in broad terms, this is roughly equivalent to US$4.3 trillion in US purchasing power, or about £3.2 trillion if treated as US dollars at current exchange rates. Hospital admissions often rise in winter, when people with COPD are more vulnerable to bacterial and viral infections that can worsen symptoms and speed up decline.
That is why the most important window for action may come much earlier in life. By the time many people are diagnosed, the disease has been developing for years. Better education about lung health at school age could help people understand that choices made in their teens and twenties may shape their breathing decades later.
COPD care has traditionally focused on treating symptoms once they appear. But by then the lungs may already be permanently damaged. Seeing COPD as a disease that develops slowly over decades could shift attention towards earlier prevention and, ultimately, reduce its human and economic cost.
