How COVID may increase diabetes risk

When the COVID pandemic began, it quickly became clear that having diabetes increases the risk for severe disease. And those who had diabetes along with other related health issues, such as heart disease, high blood pressure, or obesity, the risk for serious COVID infection and complications is even higher. There is also evidence that people with diabetes may be more likely than those without the chronic condition to develop long-COVID (new, lingering, or returning symptoms at least four weeks after an initial infection).

But since then, mounting research shows this relationship is a two-way street. Having COVID could not only make diabetes tougher to manage, but also increase the risk for diabetes in people who do not already have the condition—even kids.

What the latest research shows

Research is ongoing but one large March 2022 study published in The Lancet Diabetes & Endocrinology suggests the risk rises along with the severity of the infection, but even mild COVID cases may increase the likelihood of developing diabetes for up to a year.

For the study, scientists examined the medical records of more than 180,000 people who were diagnosed with COVID more than a month earlier. These records were compared to those of two similar groups: four million pre-pandemic patients and four million who did not have COVID. The researchers found that those infected with COVID were roughly 40 percent more likely to develop diabetes for up to a year than the non-COVID groups.

Another November 2023 meta-analysis published in Scientific Reports showed a 66 percent higher risk of diabetes in people who had COVID compared with those who didn’t. It’s unclear if these new diabetes cases are persistent over time or if they will ultimately resolve and go away.

Most of the cases involved type 2 diabetes, which occurs when the body either doesn’t produce enough insulin or becomes resistant to it. But research shows COVID is also tied to a higher risk for type 1 diabetes, which occurs when the immune system damages the pancreas, making it unable to produce insulin.

An April 2022 study of more than 27 million people in the United States published in PLOS ONE found those who were diagnosed with COVID were 42 percent more likely to develop type 1 diabetes than those who were not infected.

Type 1 diabetes can affect anyone, but it typically develops in kids, teens, or young adults. The researchers pointed out the risk for the condition post-COVID was highest among very young children, but also higher among older adults. They also noted differences across race and ethnicity. American Indian/Alaskan Native, Asian/Pacific Islander and Black people were more likely to be diagnosed than other groups.

An earlier January 2022 report from the Centers for Disease Control and Prevention (CDC) also revealed that people younger than 18-years old with COVID are more likely to be newly diagnosed with diabetes more than 30 days after their infection than those without COVID and those who had acute respiratory infections before the pandemic began.

Why does COVID increase diabetes risk?

There may be many factors involved. Some of these new diabetes cases may simply have occurred in people with prediabetes—a condition which already affects 97.6 million U.S. adults and one in five U.S. teens. People with prediabetes have higher than normal blood sugar levels and they are already at increased risk for going on to develop type 2 diabetes.

Another possible explanation: COVID could have increased diabetes risk indirectly. Excess body weight is a risk factor for severe COVID infection as well as diabetes. And over the past few years, the healthy eating and exercising habits of many Americans suffered during the pandemic.

One October 2020 study published in Frontiers in Endocrinology estimated that pandemic isolation was linked to a 33 percent decline in physical activity and a nearly 29 percent jump in sedentary behavior. In a separate September 2021 report, the CDC cautioned that school closures, disrupted routines, increased stress, and fewer opportunities for physical activity and healthy eating has resulted in weight gain, particularly among kids and teens. Younger children and those who were already overweight when the pandemic began were among those with the largest increase in body mass index (BMI), the CDC noted.

COVID harms insulin-producing cells

COVID could also increase diabetes risk directly by attacking cells in the pancreas. The virus invades human cells when its spike protein latches on to receptors called ACE2 (angiotensin converting enzyme 2).

ACE2 is present in many organs, including the lungs and heart, making them vulnerable to COVID infection. Insulin-producing cells in the pancreas also highly express ACE2. These cells can be directly attacked and damaged when the coronavirus invades. This can disrupt the production of insulin—a hormone that helps move sugar from the blood into cells where it can be used as energy.

Inflammation may be another explanation. During a severe COVID infection, the immune system produces high levels of cytokines—small proteins secreted by immune cells that respond to infections and the inflammation that result from them. These cytokines can cause insulin-producing beta cells to either stop working properly or die. This can lead to insufficient insulin production or resistance to the insulin that is produced.

How to protect yourself

Even now that the COVID public health emergency declaration has ended and we’re living alongside COVID, everyone should continue take precautions to prevent the spread of the virus. This includes being fully vaccinated and getting a booster if you’re eligible for one.

Another important way to avoid the spread of germs is to to keep your hands clean, especially public or crowded spaces. Wash them well and often with soap and water and avoid touching your face with unclean hands.

It’s important to monitor yourself or your children in the weeks following COVID infection to ensure your symptoms are resolving. Be aware of these possible signs of new onset diabetes:

• Having to urinate more frequently
• Extreme thirst
• Fatigue
• Changes in your vision
• Cuts or bruises that take longer than usual to heal
• Extreme hunger—even if you are eating the same amount or more food
• Unexplained weight loss
• Pain, loss of feeling, or tingling in your hands or feet

Young children who have developed type 1 diabetes, for example, may suddenly become increasingly tired, drink excessively, need to urinate much more often, and lose weight. Unusual nighttime accidents or bed-wetting are also possible signs of diabetes. In some cases, children with type 1 diabetes are diagnosed once they reach diabetic ketoacidosis (DKA), or when their blood sugar becomes dangerously high since they have no insulin to transport it into cells. At this point, their body is breaking down muscle and fat for energy, which triggers the production of byproducts called ketones. When ketones build up in the blood, it can be deadly.

Symptoms of type 2 diabetes, on the other hand, may develop more gradually. In some cases, there are few or no warning signs.

People who have symptoms of diabetes should see their healthcare provider who can use a blood test to make an accurate diagnosis. Those with warning signs of DKA should seek immediate medical attention as this is a life-threatening health emergency.