Scottish study: No association found over longer term
Dr. Colhoun and colleagues looked at the relationship between incident type 1 diabetes and SARS-CoV-2 infection in children in Scotland using e-health record linkage.
The study involved 1.8 million people under 35 years of age and found very weak, if any, evidence of an association between incident type 1 diabetes and SARS-CoV-2.
Examining data between March 2020 and November 2021, Dr. Colhoun and colleagues identified 365,080 individuals up to age 35 with at least one detected SARS-CoV-2 infection during follow-up and 1,074 who developed type 1 diabetes.
“In children under 16 years, suspected cases of type 1 diabetes are admitted to hospital, and 97% of diagnosis dates are recorded in the Scottish Care Information – Diabetes Collaboration register [SCI-Diabetes] prior to or within 2 days of the first hospital admission for type 1 diabetes,” Dr. Colhoun said, stressing the timeliness of the data.
“We found the incidence of type 1 diabetes diagnosis increased 1.2-fold in those aged 0-14 years, but we did not find any association at an individual level of COVID-19 infection over 30 days prior to a type 1 diabetes diagnosis, in this particular dataset,” she reported. In young people aged 15-34, there was a linear increase in incident type 1 diabetes from 2015 to 2021 with no pandemic increase.
Referring to the 1.2-fold increase soon after the pandemic started, she explained that, in 0- to 14-year-olds, the increase followed a drop in the preceding months prepandemic in 2019. They also found that the seasonal pattern of type 1 diabetes diagnoses remained roughly the same across the pandemic months, with typical peaks in February and September.
In the cohort of under 35s, researchers also found a rate ratio of 2.62 (95% CI, 1.81-3.78) within a 30-day window of SARS-CoV-2 infection, but beyond 30 days, no evidence was seen of an association, with a RR of 0.86 (95% CI, 0.62-1.21; P = .40), she reported.
She explained her reasons for not considering diagnoses within 30 days of COVID-19 as causative. Echoing Dr. Tapia, Dr. Colhoun said the median time from symptom onset to diagnosis of type 1 diabetes is 25 days. “This suggests that 50% have had symptoms for over 25 days at diagnosis.”
She also stressed that when they compared the timing of SARS-CoV-2 testing with diagnosis, they found a much higher rate of COVID-19 testing around diagnosis. “This was not least because everyone admitted to hospital had to have a COVID-19 test.”
Latest U.S. data point to a link
Meanwhile, for the new data reported in JAMA Network Open, medical student Ellen K. Kendall of Case Western Reserve University, Cleveland, matched 571,256 pediatric patients: 285,628 with COVID-19 and 285,628 with non–COVID-19 respiratory infections.
By 6 months after COVID-19, 123 patients (0.043%) had received a new diagnosis of type 1 diabetes, but only 72 (0.025%) were diagnosed with type 1 diabetes within 6 months after non–COVID-19 respiratory infection.
At 1, 3, and 6 months after infection, risk of diagnosis of type 1 diabetes was greater among those infected with SARS-CoV-2, compared with those with non–COVID-19 respiratory infection (1 month: HR, 1.96; 3 months: HR, 2.10; and 6 months: HR, 1.83), and in subgroups of patients aged 0-9 years, a group unlikely to develop type 2 diabetes.
“In this study, new type 1 diabetes diagnoses were more likely to occur among pediatric patients with prior COVID-19 than among those with other respiratory infections (or with other encounters with health systems),” noted Ms. Kendall and coauthors. “Respiratory infections have previously been associated with onset of type 1 diabetes, but this risk was even higher among those with COVID-19 in our study, raising concern for long-term, post–COVID-19 autoimmune complications among youths.”
“The increased risk of new-onset type 1 diabetes after COVID-19 adds an important consideration for risk–benefit discussions for prevention and treatment of SARS-CoV-2 infection in pediatric populations,” they concluded.
A study from the Centers for Disease Control and Prevention published in January 2022, also concluded there was a link between COVID-19 and diabetes in children, but not with other acute respiratory infections. Children were 2.5 times more likely to be diagnosed with diabetes following a SARS-CoV-2 infection, it found.
However, the study has been criticized because it pooled all types of diabetes together and did not account for other health conditions, medications that can increase blood glucose levels, race, obesity, and other social determinants of health that might influence a child’s risk of acquiring COVID-19 or diabetes.
“I’ve no doubt that the CDC data were incorrect because the incidence rate for ... diabetes, even in those never exposed to COVID-19 infection, was 10 times the rate ever reported in the U.S.,” Dr. Colhoun said. “There’s no way these data are correct. I believe there was a confusion between incidence and prevalence of diabetes.”
“This paper caused a great deal of panic, especially among those who have a child with type 1diabetes, so we need to be very careful not to cause undue alarm until we have more definitive evidence in this arena,” she stressed.
However, she also acknowledged that the new Norwegian study was well conducted, and she has no methodological concerns about it, so “I think we just have to wait and see.”
Given the inconclusiveness on the issue, there is an ongoing CoviDiab registry collecting data on this very subject.
Dr. Tapia presented on behalf of lead author Dr. Gulseth, who has reported no relevant financial relationships. Dr. Colhoun also reported no relevant financial relationships.
A version of this article first appeared on Medscape.com.