Sleep apnea and diabetes: the two-way link and what helps

Sleep apnea and type 2 diabetes often show up together, and the link seems to run both ways. Moderate to severe sleep apnea is tied to a higher risk of developing diabetes, and people with diabetes are more likely to have sleep apnea. Treating sleep apnea with CPAP can modestly improve blood sugar, and the American Diabetes Association now includes sleep apnea screening in routine diabetes care.

This guide explains the connection, what CPAP does for glucose, and how to get checked. For the wider picture, see our guide to how sleep apnea affects the body.

Is sleep apnea linked to diabetes?

Sleep apnea is linked to type 2 diabetes in studies that follow people over time. A 2013 meta-analysis in Respirology pooled six prospective studies with 5,953 people followed for 2.7 to 16 years, and found that moderate to severe sleep apnea was linked to a 63% higher risk of developing type 2 diabetes. NHLBI lists type 2 diabetes among the conditions sleep apnea may raise the risk of.

The same review found that mild sleep apnea was tied to a 22% higher risk, but that result wasn't statistically significant. The authors concluded that moderate to severe sleep apnea appears to be an independent risk factor for diabetes, meaning the link held after accounting for other factors.

The NHS also lists type 2 diabetes among the problems sleep apnea can lead to without treatment. NHLBI adds metabolic syndrome, a cluster of risk factors that includes high blood sugar and high blood pressure.

Does the link go both ways?

The link between sleep apnea and diabetes does appear to go both ways. A 2025 meta-analysis in the Journal of Diabetes Investigation pooled 35 studies and found that diabetes was about 2.3 times as common in people with sleep apnea, and sleep apnea about 2.1 times as common in people with diabetes, compared with people without each condition.

That review also found the link with diabetes was strongest in people with sleep apnea under 50. The authors concluded there is a bidirectional link between the two conditions.

A 2017 review in Chest offers one reason diabetes might feed back into sleep apnea. It says diabetic neuropathy, the nerve damage that can come with diabetes, can affect how the brain controls breathing and the reflexes that keep the upper airway open. The same review notes links between sleep apnea and type 1 diabetes and gestational diabetes too, though most of the research is in type 2.

How common is sleep apnea in people with diabetes?

Sleep apnea is very common in people with type 2 diabetes, especially those who also have obesity. The American Diabetes Association's 2026 Standards of Care say obstructive sleep apnea may affect up to 23% of people with type 2 diabetes, and any sleep-disordered breathing up to 58%.

The numbers climb with weight. The Sleep AHEAD study gave overnight sleep tests to 306 adults with obesity and type 2 diabetes. More than 86% had sleep apnea, 30.5% had moderate sleep apnea and 22.6% had severe sleep apnea. A larger waist was tied to having sleep apnea, and a higher BMI to having severe sleep apnea. The researchers urged doctors to be especially aware of sleep apnea in this group. Our guide to sleep apnea and weight gain explains how weight and sleep apnea affect each other.

How does sleep apnea affect blood sugar?

Sleep apnea seems to disturb blood sugar mainly through repeated oxygen drops and broken sleep. The 2017 Chest review says these two core features of sleep apnea, intermittent hypoxemia and sleep fragmentation, have been linked to abnormal glucose metabolism in laboratory experiments.

Researchers often look at insulin resistance, where the body's cells respond less well to insulin, so more is needed to keep blood sugar in range. A 2017 meta-analysis in the European Journal of Internal Medicine looked at people with sleep apnea who didn't have diabetes or had prediabetes. Across 23 studies with 965 people, CPAP reduced a standard measure of insulin resistance. In the four randomized trials alone, CPAP lowered fasting insulin, though the insulin resistance measure itself didn't differ from control. The authors said CPAP may reduce the risk of developing type 2 diabetes in this group, which is a hopeful but not yet proven idea.

Blood pressure tends to move alongside blood sugar here. Our guide to sleep apnea and high blood pressure covers that side of the picture.

Does CPAP improve blood sugar control?

CPAP modestly improves long-term blood sugar in people with type 2 diabetes and sleep apnea, and the more it's used, the bigger the effect. A 2023 meta-analysis in the European Respiratory Review pooled 11 randomized trials with 964 people and found CPAP lowered HbA1c by about 0.24 percentage points compared with inactive control.

The most useful finding in that review is about use. The drop in HbA1c was linked to how many hours a night people used CPAP. The authors concluded that good adherence should be a main goal for people with both conditions.

A 2021 meta-analysis in Diabetes, Obesity and Metabolism found a similar pattern. Across seven randomized trials with 691 people, CPAP improved HbA1c, fasting glucose and insulin resistance, and lowered both systolic and diastolic blood pressure.

Earlier trials disagreed with each other more, and the 2017 Chest review pointed to differences in CPAP use as one of the main reasons. That fits the newer findings. CPAP isn't a diabetes medicine, and a 0.24-point drop is modest, but it comes on top of the benefits for sleepiness, mood and blood pressure. If you're struggling with the mask, our guide to getting used to CPAP has practical fixes.

What don't we know yet?

We don't yet know how much treating sleep apnea lowers the chance of developing diabetes, or how big the long-term benefit for blood sugar is. The evidence is promising but still has real gaps, and it helps to know them before expecting too much from CPAP alone.

The risk findings are strongest for moderate to severe sleep apnea. In the 2013 Respirology review, the higher risk with mild sleep apnea could have been down to chance. On prevention, the 2017 European Journal of Internal Medicine review drew mostly on non-randomized studies, and its four randomized trials didn't show a clear change in insulin resistance or fasting glucose. The CPAP effect on HbA1c in people who already have diabetes is real in pooled trials but modest in size.

Newer treatments are also still being studied. The ADA says more research is needed on how the newer weight-loss medicines affect sleep apnea in people with diabetes.

None of this is a reason to skip treatment. It's a reason to treat sleep apnea and diabetes as two conditions that each need their own care.

Should people with diabetes be screened for sleep apnea?

People with diabetes should be screened for sleep apnea, according to the American Diabetes Association. Its 2026 Standards of Care list screening for obstructive sleep apnea among the items to cover at diabetes visits, and say sleep apnea should be evaluated in people with suggestive symptoms such as excessive daytime sleepiness, snoring and witnessed breathing pauses.

The ADA also lists sleep apnea alongside obesity and fatty liver disease as common conditions to review in a person's history. It says sleep apnea treatment, including lifestyle changes, CPAP, oral appliances and surgery, significantly improves quality of life and blood pressure management. It notes that two recent trials found the medicine tirzepatide substantially reduced sleep apnea severity in adults with obesity but without diabetes, and that more research is needed in people with diabetes.

In practice, tell your diabetes team if you snore loudly, wake up gasping or feel sleepy during the day. The NHS says to see a GP if your breathing stops and starts while you sleep, you make gasping, snorting or choking noises, or you always feel very tired. Our list of sleep apnea warning signs can help, and our guide to the home sleep apnea test explains what testing involves.

What can you do to help both?

You can help both conditions by getting sleep apnea diagnosed and treated, and by working on the habits that affect both. The NHS says sleep apnea can sometimes be treated with lifestyle changes like losing weight, giving up smoking and drinking less alcohol, though many people need CPAP.

The NHS also suggests exercising regularly, keeping regular sleep hours, sleeping on your side and avoiding sleeping pills unless a doctor recommends them. Many of these overlap with diabetes care. If you wake with a dry mouth and wonder whether it's your blood sugar or your breathing, our guide to dry mouth at night and diabetes sorts through the causes.

If you have sleep apnea, ask your doctor whether you should be checked for diabetes. If you have diabetes, ask whether you should be checked for sleep apnea. Our guide to sleep apnea treatment options covers what comes after a diagnosis.

This article is general information, not medical advice. Talk to your doctor about your own situation.

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* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.