People infected with the coronavirus were much more likely to be diagnosed with type 2 diabetes within a year of being infected, compared to those who had not been exposed to the virus, researchers in Canada reported on Tuesday.
Men were more likely to develop diabetes than women, the scientists found. People who were so sick they were hospitalized were more than twice as likely to be diagnosed with diabetes as those who were not infected.
People admitted to intensive care were more than three times more likely to develop diabetes, the researchers also found. The findings add to a growing body of evidence on the long-term effects of Covid.
“It’s definitely a concern in terms of long-term outcomes,” said Dr. Naveed Z. Janjua, lead author of the paper and a professor in the School of Population and Public Health at Colombia University. -British.
“With a respiratory infection, you usually think, ‘Seven or eight days and I’m done, that’s it,'” he added. “Here we see lingering effects that last a lifetime.”
The study, published in JAMA Network Open, used a large dataset from British Columbia to compare diabetes diagnoses among more than 125,000 people who had tested positive for Covid in 2020 and 2021 with those of more than 500,000 people not exposed during the same period.
Covid vaccines became available in December 2020, and the majority of participants in both exposed and unexposed groups had not been fully vaccinated.
More than a dozen studies have looked at the link between Covid and diabetes, and a majority have reported increased diagnoses following infection, as well as higher risks for men and people with serious illness. .
However, the results do not prove that the infection causes diabetes. Experts said it was possible, for example, that patients recovering from Covid were more likely to be diagnosed with diabetes simply because they were receiving more regular care.
Still, there are plausible biological explanations for a link between the two conditions, said Dr. Pamela Davis, professor of medicine at Case Western Reserve University in Cleveland, who co-authored a commentary accompanying the study.
“It’s reasonable to ask, ‘Is this a real increase, or is this just something that accelerated the diabetes that was happening to people anyway, but they got it earlier?'” he said. Dr. Davis in an interview.
“But even if it’s just an acceleration, it’s going to be expensive,” she added. “Human suffering, the risk of complications in the eyes, blood vessels, heart, kidneys, lost productivity and work days, all of this will be accelerated. I am worried about this.
The coronavirus infects beta cells in the pancreas that make insulin, Dr. Davis said, and causes cell death. These cells are dotted with ACE2 receptors that the virus uses as a gateway.
“If you put pancreatic beta cells in a culture dish, the virus will greedily infect those cells and destroy them,” she said.
Stress also plays a role in the development of diabetes, and the inflammatory response that accompanies Covid has been linked to the destruction of beta cells. People with severe Covid can also produce antibodies that attack the patient’s own body.
Other viral infections have also been linked to the development of diabetes, according to Dr. Janjua, whose pre-pandemic research focused on hepatitis.
“With hepatitis C, we have strong evidence that the infection is associated with an increased risk of diabetes as well as cardiovascular outcomes and many other systemic outcomes outside of the liver,” Dr. Janjua said.
The new study found adults who tested positive for the virus were 17% more likely to develop diabetes within a year of testing positive. Men were 22% more likely to develop diabetes than unexposed people. The elevated risk for women overall was not statistically significant unless they were hospitalized or admitted to an intensive care unit.
Researchers matched infected and unexposed people by age and sex, and made adjustments to account for differences in underlying health conditions, socioeconomic status, vaccination status and other factors.
They calculated that of all new cases of diabetes, some 3.4% could be attributed to Covid infection. For men, 4.75% of new cases were attributed to Covid.