Get emergency care for severe or rapidly worsening breathlessness, struggling to breathe, new confusion or unusual drowsiness, or sudden chest pain with breathlessness. Call your local emergency number.
Key points
- COPD and lung cancer share their main cause, tobacco smoke, and often occur in the same person. GOLD calls lung cancer a major cause of death in people with COPD.
- COPD causes long-term breathlessness, cough and phlegm. It is confirmed only by spirometry showing a post-bronchodilator FEV1/FVC ratio below 0.7.
- Coughing up blood, a cough that changes or will not go away, unexplained weight loss, hoarseness, or repeated chest infections need prompt medical review, especially in anyone who smokes or used to.
- In the US, the USPSTF (2021) recommends yearly low-dose CT screening for adults aged 50 to 80 with at least 20 pack-years who smoke now or quit within the past 15 years. Other countries use different rules or have no programme.
- GOLD advises that everyone who smokes should be strongly encouraged and supported to quit. Medicines and counselling increase long-term quit rates.
How common they are
WHO lists COPD as the third leading cause of death worldwide, with 3.4 million deaths in 2023 (about 6% of all deaths). Nearly 90% of COPD deaths in people under 70 occur in low- and middle-income countries. Lung cancer is the leading cause of cancer cases and cancer deaths worldwide, with an estimated 2.5 million new cases and 1.8 million deaths in 2022. In the US, the CDC reports that nearly 16 million adults have COPD, and many more are undiagnosed.
What causes them
COPD develops from the interaction of genes and environment over a lifetime. WHO notes that tobacco smoking causes over 70% of COPD in high-income countries but only 30–40% in low- and middle-income countries, where smoke from cooking and heating with wood, dung, crop waste or coal is a major cause. Other risks include second-hand smoke, outdoor air pollution, workplace dusts, fumes and chemicals, poor lung growth from prematurity or childhood infections, childhood asthma, and alpha-1 antitrypsin deficiency, a rare inherited condition that can cause COPD at a young age.
Lung cancer: NCI names current or past smoking as the most important risk factor, and risk rises with earlier starting age, more cigarettes and more years smoked. Other risks include second-hand smoke, radon in homes or workplaces, asbestos and other workplace carcinogens, air pollution, previous chest radiotherapy, HIV infection, family history, and beta-carotene supplements in heavy smokers. WHO estimates that 60–70% of preventable lung cancer is due to tobacco. People who have never smoked can also develop it.
Recognising COPD
Symptoms usually appear from mid-life onwards and progress slowly:
- breathlessness during everyday activities that gradually limits what you can do
- a chronic cough, often the first symptom and often dismissed as a "smoker's cough", with or without phlegm
- wheeze and tiredness
- repeated chest infections
GOLD advises considering COPD in anyone with these symptoms or a history of exposure to risk factors. Spirometry is required to make the diagnosis: a post-bronchodilator FEV1/FVC below 0.7 confirms airflow obstruction that is not fully reversible. WHO notes that spirometry is often unavailable in low- and middle-income countries, so COPD is frequently missed. COPD and asthma share symptoms and can occur together.
Exacerbations (flare-ups) are episodes in which breathlessness, cough or phlegm worsen over a few days, up to 14 days, often with a fast breathing or heart rate. They are usually triggered by viral or bacterial infections or air pollution. GOLD notes that pneumonia, a blood clot in the lung, heart failure and a collapsed lung can look like a flare-up. From 2026, GOLD treats even one moderate flare-up as a reason to review treatment.
Recognising lung cancer
Lung cancer may cause no symptoms early on and is sometimes found on an X-ray done for another reason. NCI and WHO list:
- a cough that does not go away or gets worse
- coughing up blood or blood-streaked phlegm (haemoptysis)
- chest pain or discomfort, shortness of breath or wheezing
- hoarseness
- loss of appetite, weight loss without a known cause, and tiredness
- trouble swallowing
- swelling of the face or of the veins in the neck
- chest infections that keep coming back
In people with COPD these symptoms can be mistaken for the usual cough and breathlessness. WHO notes that early symptoms are often mild or dismissed, which delays diagnosis. A change in a long-standing cough, new blood in the phlegm or unexplained weight loss should never be put down to COPD without assessment.
Lung cancer screening
US (USPSTF, March 2021, grade B): annual low-dose CT for adults aged 50 to 80 who have smoked at least 20 pack-years and still smoke or quit within the past 15 years. One pack-year is 20 cigarettes a day for a year. Screening stops once a person has not smoked for 15 years, or if a health problem substantially limits life expectancy or the ability or willingness to have lung surgery. In 2021 the USPSTF widened the criteria from age 55 and 30 pack-years. The decision should be shared, after discussing benefits and harms such as false-positive results.
GOLD 2026 recommends annual low-dose CT for people with COPD who have a smoking history, in line with general population recommendations. It does not recommend screening for people whose COPD is not linked to smoking, because evidence is lacking.
Other countries: eligibility ages, smoking thresholds and whether a programme exists at all vary. WHO advises that, in well-resourced health systems, screening can be considered for defined high-risk groups, particularly current or former heavy smokers, with quality assurance and follow-up. Check what your national health service offers.
Red flags / when to get urgent help
Emergency care now for:
- severe breathlessness, fast breathing, or needing the neck and chest muscles to breathe
- confusion, drowsiness or reduced alertness. GOLD lists these mental status changes, with worsening oxygen or carbon dioxide levels, as signs of respiratory failure
- sudden chest pain or sudden new breathlessness. GOLD notes that a blood clot in the lung, a collapsed lung or heart failure can mimic a COPD flare-up
GOLD's indications for hospital care in a COPD flare-up include signs of respiratory failure, failure to respond to initial treatment, serious other illness such as heart failure or arrhythmia, and insufficient support at home.
See a doctor within days for any blood in the phlegm, unexplained weight loss, persistent hoarseness, a new or changed cough, swelling of the face or neck, or a flare-up that is not settling with your action plan.
Frequently asked questions
Is a smoker's cough normal?
No. A daily cough is often the first symptom of COPD. Anyone with a persistent cough who smokes or used to smoke should ask for spirometry, and for review of any change in that cough.
Does COPD mean I will get lung cancer?
No, but lung cancer is a major cause of death in people with COPD and both share risk factors. Stopping smoking and joining screening if eligible both help.
What is a pack-year?
It measures lifetime smoking. One pack-year equals smoking 20 cigarettes (one pack) a day for one year, so 10 a day for 40 years is also 20 pack-years.
I have never smoked. Can I get COPD or lung cancer?
Yes. Household and outdoor air pollution, workplace exposures, radon, second-hand smoke, early-life lung problems and genetic factors all contribute.
Sources
- Global Initiative for Chronic Obstructive Lung Disease. 2026 GOLD Report and Pocket Guide. goldcopd.org
- World Health Organization. Chronic obstructive pulmonary disease (COPD), fact sheet. who.int
- World Health Organization. Lung cancer, fact sheet. who.int
- US Centers for Disease Control and Prevention. About COPD. cdc.gov
- US National Cancer Institute. Non-small cell lung cancer treatment (PDQ), patient version. cancer.gov
- US Preventive Services Task Force. Lung cancer: screening, final recommendation, March 2021. uspreventiveservicestaskforce.org
This article is for education and does not replace advice from a doctor, nurse or pharmacist who knows the person's history. Screening eligibility depends on your country's programme.
