Up to one in 20 new diabetes cases could be related to Covid infection, data suggests.
The research adds to mounting evidence the pandemic may be contributing to a rapidly escalating diabetes crisis, with individuals who have experienced more severe Covid at greatest risk.
However, lifestyle factors such as being overweight or obese continue to be the main driver for the increase, with 4.3 million officially diagnosed cases in the UK alone.
Although previous research has hinted that Sars-CoV-2 infection may increase the risk of developing diabetes – possibly by damaging insulin-producing cells in the pancreas – these studies were either relatively small or limited to specific groups of individuals, such as US military veterans, who may not represent the general population.
To delve deeper, Prof Naveed Janjua at the University of British Columbia in Vancouver, Canada, and his colleagues turned to the British Columbia Covid-19 Cohort, a surveillance platform that links data on Covid infections and vaccinations with sociodemographic and administrative health data.
They examined records from 629,935 people who took a PCR test for Covid and found those who tested positive were significantly more likely to experience a new diagnosis of type 1 or type 2 diabetes in the following weeks and months – with 3-5% of new diabetes cases attributable to Covid overall.
“Another way to phrase this is out of 100 people with diabetes, 3-5% are related to Sars-CoV-2 infection,” said Janjua, whose research was published in the JAMA Network Open medical journal.
Men and women who were hospitalised with Covid appeared to be at greatest risk. However, among the general population, the association between Sars-CoV-2 infection and diabetes risk was significant only for men – possibly due to sex-specific immune responses to the virus.
“Given the large number of people infected with Covid-19, these excess diabetes cases could translate into very large population level burden of diabetes which could strain already stretched healthcare systems,” Janjuar said.
“This highlights the importance of healthcare organisations and medical professionals being mindful of the possible long-term outcomes of Covid-19. It may be important to monitor individuals who have recovered from Covid-19 for diabetes, especially those who had more severe disease during the acute phase of infection, as early detection and treatment can be critical in managing diabetes. In addition, diet and physical activity may help in controlling diabetes risk.”
Dr Caroline Ponmani, a consultant in paediatric emergency medicine at Queen’s hospital in Romford, Essex, who has been investigating links between Covid and the development of type 1 diabetes in children, said: “This is new and highly interesting data which has long-term implications in resource planning and allocation. It has a longer follow-up time compared to other studies, and it appears that the incidence of new onset diabetes continues to be high after Sars-CoV-2 infection.”
Although individuals in this study were predominantly diagnosed with type 2 diabetes, which is more common in adults, Ponmani’s research suggests Covid infection is more likely to be associated with the development of type 1 diabetes in children.
During the first year of the pandemic she identified a 17% increase in new onset diabetes cases among children across the UK and Ireland, compared with a background incidence of 3-5% over the past 10 years. More than 95% of these children were diagnosed with type 1 diabetes.
The latest data from the National Paediatric Diabetes Audit for England and Wales also reports that 2021 and 2022 have been high incidence years for new onset type 1 diabetes in children, Ponmani said.
Even so, further research is needed to confirm that the virus is the direct cause of people’s diabetes. Another possibility is that more cases are being picked up as a result of screening when people with Covid are admitted to hospital, or that some of these cases are transient and may resolve over time. “What we need to find out is longer term, is this true diabetes?” said Kamlesh Khunti, a professor of primary care diabetes and vascular medicine at the University of Leicester.
Assuming the virus is directly to blame, the underlying mechanism also still needs to be teased out.
“Some studies have suggested that Sars-CoV-2 could infect cells that produce insulin in pancreas, leading to alteration of their function and insulin production, while other studies are not conclusive on this theory,” said Janjua. “It is also suggested that chronic low-grade inflammation common in people with obesity, a problem with the autonomic nervous system, hyperactivated immune response or autoimmunity, could also play a role in diabetes.”
