What Is COPD?

What This Article Covers

Chronic obstructive pulmonary disease (COPD) is one of the most common serious lung conditions in the world, yet it's often diagnosed late because early symptoms get mistaken for normal aging. This article covers what COPD is, its causes, symptoms, diagnosis, standard treatment, and prevalence — closing with an honest look at where stem cell research stands today, a field still experimental and unapproved.

What Is COPD?

COPD is an umbrella term for progressive lung diseases that make breathing increasingly difficult. It usually combines emphysema, in which the lungs' tiny air sacs (alveoli) are damaged and lose elasticity, and chronic bronchitis, in which the airways are chronically inflamed and produce excess mucus. Most people with COPD have features of both. Because the airway damage is largely permanent, COPD is lifelong and progressive rather than something that resolves on its own.

Causes and Risk Factors

Cigarette smoking (including secondhand smoke) is the dominant cause in the U.S. and other high-income countries; most people with COPD smoke or formerly smoked. Air pollution, including indoor smoke from burning biomass fuels, is a major cause worldwide, especially in lower-income countries. Long-term exposure to workplace dust and chemical fumes can also cause COPD in nonsmokers, as can alpha-1 antitrypsin deficiency, a genetic condition that leaves the lungs poorly protected, including in younger people. Childhood respiratory infections and underdeveloped lungs can raise later risk too.

Symptoms

Symptoms usually develop gradually over years and are easy to dismiss at first: worsening shortness of breath with activity, a chronic mucus-producing cough, wheezing, chest tightness, frequent respiratory infections, and fatigue. In advanced disease, basic activities like walking or self-care become difficult. Because decline is gradual, many people unconsciously limit activity to avoid breathlessness rather than seek a diagnosis — one reason COPD is widely underdiagnosed.

How It's Diagnosed

The core diagnostic test is spirometry: a person exhales forcefully into a tube connected to a machine measuring airflow. Clinicians check the ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC); a postbronchodilator ratio below 0.70 confirms persistent airflow limitation consistent with COPD. The GOLD (Global Initiative for Chronic Obstructive Lung Disease) 2026 report recommends interpreting results alongside symptoms and exacerbation history, and urges proactive testing of current or former smokers and anyone with unexplained breathlessness or chronic cough, since COPD is so often missed until fairly advanced.

Standard Treatment Today

There is no cure for COPD, but established treatments ease symptoms, reduce flare-ups ("exacerbations"), and sometimes slow progression. Smoking cessation is the single most effective step. Inhaled bronchodilators (long-acting beta-agonists and muscarinic antagonists) are the foundation of maintenance therapy, often combined with an inhaled corticosteroid as "triple therapy" for frequent exacerbations, particularly with elevated blood eosinophils. Biologics such as dupilumab and mepolizumab are FDA-approved for COPD patients with type 2 (eosinophilic) airway inflammation and reduce exacerbations in that subgroup. Other core elements: pulmonary rehabilitation (supervised exercise, education, breathing techniques), supplemental oxygen for low blood oxygen, vaccination against flu, pneumococcal disease, and COVID-19, and, in select severe cases, lung volume reduction surgery or transplantation.

Epidemiology

COPD is extremely common. A 2023 CDC data brief found about 3.8% of U.S. adults have diagnosed COPD, rising sharply with age — from under 1% among 18-24-year-olds to roughly 10.5% among those 75 and older — and higher among women and lower-income households. NHLBI puts the total above 14 million U.S. adults, with many more believed undiagnosed, and notes COPD ranks among the leading causes of death and disability nationally. Globally, tobacco use and, in lower-income regions, air pollution drive its status as a top cause of death worldwide.

Where Stem Cell Research Stands

Stem cell therapy for COPD remains experimental and is not FDA-approved. Most research has used mesenchymal stem cells (MSCs) — from bone marrow, fat, or umbilical cord tissue — given intravenously for their anti-inflammatory signaling, not a proven ability to regenerate destroyed lung tissue.

The most-cited trial, a placebo-controlled study published in CHEST in 2013, randomized 62 patients with moderate-to-severe COPD to four monthly infusions of allogeneic MSCs or placebo over two years. Safety was reassuring — no infusion-related toxicities or serious adverse events — but lung function, quality of life, and exacerbation rates didn't differ significantly between groups; a drop in the inflammatory marker CRP among patients with elevated baseline levels was flagged as a signal worth exploring, not evidence of benefit. A smaller 2020 pilot study of 20 men using umbilical cord-derived MSCs likewise found no serious safety concerns over six months, with improved breathlessness scores and fewer exacerbations but no significant change in lung function or walk distance.

Together, this evidence shows a consistent safety profile for MSC infusions but inconsistent, generally modest efficacy, especially on objective measures like lung function. Regulators and researchers don't consider current data sufficient to support stem cell therapy as standard care; larger, controlled trials are needed before any cell-based therapy could be considered for routine use.

Bottom Line

COPD is a common, serious, largely preventable lung disease rooted overwhelmingly in smoking and other inhaled irritants, diagnosed through spirometry and managed with bronchodilators, inhaled steroids, biologics for select patients, pulmonary rehabilitation, and oxygen therapy. Stem cell research has produced encouraging safety data and occasional symptom-level improvements, but not yet the consistent lung-function benefit needed to support use outside a formal clinical trial. Anyone considering an unproven cell-based treatment for COPD should discuss it with a pulmonologist and view it as experimental, not a substitute for guideline-based care.