How does diabetes affect the lungs? Studies that pool many groups find that people with type 2 diabetes tend, on average, to have lower lung function test results than people without it. A 2021 meta-analysis in ERJ Open Research combined 66 studies, with 11,134 people with type 2 diabetes and 48,377 comparison participants. It found forced expiratory volume in 1 second (FEV1) averaged 7.15 percentage points lower and forced vital capacity (FVC) 9.21 points lower, measured against the expected value for each person. This describes a pattern in groups. It does not mean every person with diabetes has a lung problem, and researchers still disagree on whether diabetes makes lung function decline faster over time.
Key takeaways
- A 2021 analysis of 93 studies in Diabetes & Metabolism found FEV1 and FVC averaged 5.65 and 5.91 percentage points of predicted value lower in people with diabetes. The 66-study analysis found a similar pattern, and the gap held regardless of sex, body mass index (BMI), smoking, or region.
- The link runs both ways. In the 93-study analysis, every 10% lower baseline FVC went with a 13% higher risk of developing diabetes. Five long-term studies disagreed on whether diabetes speeds up lung decline.
- Both analyses describe considerable differences between studies and call for longer follow-up research. These are associations, not proof of cause.
- In 16,242 UK adults with type 2 diabetes, lower lung function went with more heart and blood vessel disease over a median 13.9 years.
- The Centers for Disease Control and Prevention (CDC) lists diabetes among the conditions people with chronic obstructive pulmonary disease (COPD) are more likely to have. Asthma and COPD each have their own guide below.
- Sudden or severe trouble breathing, or breathlessness with chest pain, is an emergency. New or worsening breathlessness deserves a call to your clinician.
Diabetes and the Lungs: The Short Answer
- Lung function tends to be lower, on average. Two 2021 meta-analyses found gaps of roughly 6 to 9 percentage points of predicted value.
- The reason is not settled. Researchers have proposed ideas about the smallest blood vessels, scarring, and weight, and none is proven.
- The link may run both ways. Lower lung function has also been linked to a higher chance of developing diabetes later.
- You may not feel it. MedlinePlus says some people with advanced lung disease never feel short of breath, so a test result and a symptom do not always match.
- Specific conditions have their own guides. Asthma, COPD, and other causes of breathlessness are covered in separate articles.
What "Lung Function" Means
MedlinePlus says lung function tests, also called pulmonary function tests, check how well your lungs are working and are often used to help diagnose and monitor lung diseases such as asthma and COPD. The most used test is spirometry, which measures how much air you breathe out and how fast you can blow it out.
Two numbers appear in most of the studies below. FEV1 is the amount of air you can blow out in the first second. FVC is the total amount you can blow out after a deep breath. Results are usually compared with the value expected for someone of the same age, height, and sex, which is why they are reported as a percent of predicted.
What the Research Shows
| Study | Who was studied | What it found | Limits |
|---|---|---|---|
| Díez-Manglano and Asín Samper, 2021 | 66 studies: 11,134 people with type 2 diabetes and 48,377 comparison participants | FEV1 7.15 points lower, FVC 9.21 points lower, and gas-exchange capacity 7.13 points lower. No difference in the FEV1/FVC ratio | Considerable differences between studies. Only half had 50 or more people with diabetes. The authors call for long-term studies |
| Zhang and colleagues, 2021 | 93 studies | FEV1 5.65 and FVC 5.91 points lower. A restrictive spirometry pattern was more likely (odds ratio 2.88 in cross-sectional studies, hazard ratio 1.57 in prospective cohorts). Poorer function went with microvascular complications and poor glycemic control | Five long-term studies were inconsistent on whether diabetes speeds decline |
| Chen and colleagues, 2025 | 16,242 UK Biobank adults with type 2 diabetes, followed a median 13.9 years | Compared with preserved lung function, heart and blood vessel disease risk was 1.19 times higher with an obstructive pattern and 1.47 times higher with a restrictive pattern | Observational. It shows an association and cannot show that lung function caused the heart outcomes |
| He and colleagues, 2026 | 31 studies of COPD and diabetes | The two conditions were linked in both directions, but the adjusted links were weaker (see the COPD guide) | The authors rate the certainty of evidence as very low |
| Mubanga and colleagues, 2025 | 5,299,245 Swedish adults | Asthma and type 2 diabetes were linked (odds ratio 1.47), and part of the link was shared family factors | Cross-sectional, so it cannot show which came first |
The authors of the 66-study analysis estimate the gap in FEV1 and FVC at about 300 mL. They note that this looks modest, and that differences of 100 to 150 mL have been considered meaningful in trials of airway-opening medicines in COPD. They also found reduced results for tests of smaller airways and peak flow, which they say suggests changes in both large and small airways.
Why Might Diabetes Affect the Lungs?
Nobody knows for certain. The 66-study analysis lists ideas that other researchers have proposed, and describes them as possible explanations.
- The smallest blood vessels and lung lining. Autopsies of people with diabetes have found a thickened basement membrane, the thin supporting layer, around the lungs' tiny blood vessels and lining cells. The authors link this thickening to inflammation and scarring, which can make lung tissue less elastic.
- Long-term high blood sugar. The authors cite proposed chemical pathways in which sustained high blood sugar raises oxidative stress and a sugar-binding process that may add to lung scarring.
- Weight. Extra fat on the chest wall and belly can limit how the rib cage and diaphragm move. The lung function gap was also found in people with diabetes at a normal weight, so weight alone does not explain it.
- Smoking and other exposures. The gap held in studies that included only nonsmokers. The authors had no explanation for why it was larger in those studies and suggested exposures such as air pollution or smoke from biomass fuels may play a part in some regions.
These ideas come from autopsy reports, lab work, and small studies. They are not shown to explain lung function in any one person.
Would You Notice It?
Possibly not. MedlinePlus says breathing difficulty is a feeling only the person can judge. Some people feel breathless with mild effort without any medical condition, and others with advanced lung disease may never feel short of breath. A modest drop in a test result can exist without a change you would notice. A change in how you feel is still worth reporting, whatever a test shows.
Lung Conditions and Diabetes
| Topic | What the sources say | Read next |
|---|---|---|
| Asthma | A large Swedish register study and recent reviews link asthma and type 2 diabetes, and reviews link diabetes to worse asthma outcomes. Steroid medicines for asthma are a separate question | Is asthma linked to diabetes? |
| COPD | A 2026 meta-analysis found diabetes in about 17% of people with COPD and COPD in about 17% of people with diabetes. The adjusted links were weaker | Is COPD linked to diabetes? |
| Breathlessness | Heart, kidney, blood count, lung, and other causes, plus a diabetes emergency | Can diabetes cause shortness of breath? |
| Lung infections | The American Diabetes Association (ADA) says people with diabetes are at increased risk for pneumococcal infection | Do diabetics need a pneumonia vaccine? |
| Breathing during sleep | The ADA says up to 23% of people with type 2 diabetes may have obstructive sleep apnea | Sleep apnea and type 2 diabetes |
| Smoking | CDC says smoking raises the risk of type 2 diabetes and worsens it once present | Does smoking affect blood sugar? |
Vaccines and Sleep
The ADA's Standards of Care in Diabetes—2026 say pneumococcal pneumonia is a common, preventable disease and that all people with diabetes should receive one of the CDC-recommended pneumococcal vaccines. They add that people with chronic conditions such as diabetes have a higher risk of severe illness from respiratory syncytial virus (RSV). CDC lists COVID-19, flu, and pneumococcal vaccines as ways to help prevent lung infections in people with COPD. Which vaccines you are due for depends on your age and history, so that is a question for your clinician. Our guides on vaccines for people with diabetes and whether diabetes weakens the immune system go through the details.
On sleep, the ADA says obstructive sleep apnea should be evaluated in people with suggestive symptoms, such as excessive daytime sleepiness, snoring, and witnessed pauses in breathing.
Smoking and Your Lungs
CDC says people who smoke have a 30% to 40% higher risk of developing type 2 diabetes than people who do not, and that smoking can worsen diabetes and cause complications. CDC also says that when you stop smoking, your circulation and lungs improve within 2 weeks to 3 months. Nicotine replacement products contain nicotine, which raises blood sugar, so CDC advises talking with your doctor about using them if you have diabetes. CDC lists free, confidential quit coaching at 1-800-QUIT-NOW.
Breathing Changes to Report
| What you notice | What the sources say | What to do |
|---|---|---|
| Breathing trouble that starts suddenly or makes talking hard, or someone stops breathing | MedlinePlus lists these as reasons to go to the emergency room or call the local emergency number | Call 911 |
| Breathlessness with chest pain or pressure, fainting, or nausea | The American Lung Association says handle this as a medical emergency | Call 911 |
| Fast, deep breathing, fruity-smelling breath, vomiting you cannot keep fluids down, or blood sugar that stays at 300 mg/dL or above | CDC lists fast, deep breathing as a sign of diabetic ketoacidosis, and lists the other signs as reasons to go to the emergency room or call 911 | Call 911 or go to the emergency room |
| Breathlessness after slight activity or at rest, waking at night short of breath, needing to sleep propped up, wheezing, or fever | MedlinePlus says to see your provider if any of these occur with breathing difficulty | Call your clinician promptly |
| Lasting cough, wheezing, trouble taking deep breaths, or extra mucus | CDC lists these as common COPD symptoms and says to talk with your doctor | Make an appointment |
| Breathlessness that lasts four weeks or longer | The American Lung Association says this may be a sign of a chronic health condition | Make an appointment |
Do Adults With Diabetes Need a Lung Test?
The ADA's 2026 section on comorbidities does not include a recommendation to test lung function in everyone with diabetes. It covers vaccines and sleep apnea. MedlinePlus says your provider may order lung function tests if you have symptoms such as shortness of breath, wheezing, cough, or a tight feeling in your chest, or if you have a lung condition or another condition that could damage your lungs.
The UK Biobank authors found that adding lung function measurements improved prediction of heart and blood vessel disease beyond a standard risk score. That is a research finding. Whether a lung test makes sense for you is a question for your clinician.
Questions to Ask Your Care Team
- Have I ever had a breathing test, and would one help in my situation?
- Could any breathlessness I have come from my heart, kidneys, blood count, lungs, or sleep?
- Which vaccines for lung infections am I due for?
- Do any of my medicines, including steroid inhalers or tablets, affect my blood sugar?
- If I smoke, or used to, what help is available to quit?
- Which breathing changes should send me for urgent care?
Frequently Asked Questions
Can diabetes damage the lungs?
Studies link diabetes to lower lung function, but they show an association and do not prove damage in any one person. Two 2021 analyses found average gaps of about 6 to 9 percentage points of predicted value in FEV1 and FVC. Researchers have proposed ideas such as thickened lung blood vessel walls and scarring, and these are not proven. Tell your clinician about new breathing symptoms.
Does diabetes cause shortness of breath?
It can be linked in several ways, but breathlessness has many possible causes. MedlinePlus lists heart, lung, airway, blood count, and other problems, and CDC lists fast, deep breathing as a sign of diabetic ketoacidosis. A clinician sorts out which cause applies, so new or worsening breathlessness should be reported.
Does lower lung function mean I have asthma or COPD?
No. A lower test result can exist without either diagnosis. The 2021 pooled analysis of type 2 diabetes found no difference in the FEV1/FVC ratio, while asthma and COPD are diagnosed by a clinician using symptoms and tests such as spirometry. Ask what your own results mean.
Can better blood sugar control improve lung function?
The 93-study analysis found that poor glycemic control and microvascular complications went with poorer lung function. That is an association. The authors say more research is needed on whether changes in blood sugar affect the lungs, so ask your care team about your own targets.
Should I get a pneumonia vaccine if I have diabetes?
The ADA says all people with diabetes should receive one of the CDC-recommended pneumococcal vaccines. Which vaccine and when depends on your age and history, so ask your clinician or pharmacist. Our pneumonia vaccine guide explains the options.
When is trouble breathing an emergency?
MedlinePlus says to go to the emergency room or call the local emergency number if breathing difficulty comes on suddenly or seriously interferes with breathing and talking, or if someone stops breathing. The American Lung Association says breathlessness with chest pain or pressure, fainting, or nausea is a medical emergency.
References
- Díez-Manglano J, Asín Samper U. "Pulmonary function tests in type 2 diabetes: a meta-analysis." ERJ Open Research. 2021;7(1):00371-2020. Accessed November 2026.
- Zhang RH, Cai YH, Shu LP, et al. "Bidirectional relationship between diabetes and pulmonary function: a systematic review and meta-analysis." Diabetes & Metabolism. 2021;47(5):101186. Accessed November 2026.
- Chen C, Huang Z, Liu L, et al. "Lung Function Impairment and Risks of Incident Cardiovascular Diseases and Mortality Among People With Type 2 Diabetes: A Prospective Cohort Study." Diabetes Care. 2025;48(5):728–736. Accessed November 2026.
- He S, Karunakaran M, Rushender R, et al. "Chronic obstructive pulmonary disease and diabetes mellitus: a bidirectional meta-analysis of risk and comorbidity burden." Frontiers in Endocrinology. 2026;17:1912659. Accessed November 2026.
- Mubanga M, Gong T, Smew AI, et al. "Association between asthma and type 2 diabetes in a Swedish adult population: a register-based cross-sectional study." Thorax. 2025;80(6). Accessed November 2026.
- MedlinePlus. "Lung Function Tests." Accessed November 2026.
- MedlinePlus. "Breathing difficulty." Medical Encyclopedia. Accessed November 2026.
- American Lung Association. "Shortness of Breath: Causes, Warning Signs & When to Seek Help." Accessed November 2026.
- Centers for Disease Control and Prevention. "About COPD." Accessed November 2026.
- Centers for Disease Control and Prevention. "Diabetes and Smoking." Accessed November 2026.
- Centers for Disease Control and Prevention. "Diabetic Ketoacidosis." Accessed November 2026.
- American Diabetes Association Professional Practice Committee for Diabetes. "4. Comprehensive Medical Evaluation and Assessment of Comorbidities: Standards of Care in Diabetes—2026." Diabetes Care. 2026;49(Suppl. 1):S61–S88. Accessed November 2026.
Next Steps
If you have noticed new breathlessness, write down when it happens, what you were doing, and any other symptoms, and bring the notes to your next visit. Call emergency services for sudden or severe trouble breathing or for breathlessness with chest pain.
For adults with type 2 diabetes or prediabetes who want lifestyle education alongside clinical care, the Done With Diabetes™ program, a type 2 diabetes protocol, organizes learning about meals, movement, sleep, and stress. It does not diagnose or treat lung conditions or diabetes, interpret symptoms or test results, change medicines, or replace your care team.