COVID-19 and Diabetes: What's the Link?

Among the various long-term effects researchers have investigated since the pandemic began, one of the more striking is a consistent link between COVID-19 infection and an increased risk of developing diabetes afterwards. It's not a small or isolated finding either, having now been reported across multiple large studies covering millions of people.

What the largest studies have found

A systematic review and meta-analysis covering 8 cohort studies and more than 47 million participants found COVID-19 was associated with a 66% higher risk of developing diabetes compared with people who hadn't had COVID-19. A separate US study of over 181,000 military veterans found those who'd had COVID-19 faced a 40% higher risk of new diabetes a year later compared with people who hadn't been infected. Other research has put the increase at around 60%, generally for type 2 diabetes specifically, reinforcing that this isn't a one-off finding from a single study but a pattern showing up repeatedly across different populations and research groups.

Is the risk the same for everyone?

No. Research has found the incidence and relative risk of new-onset diabetes and high blood sugar after COVID-19 tend to be more pronounced in the period shortly after infection and among men specifically. Some cohort studies have suggested the increased risk is only clearly observed in people who were hospitalised for COVID-19, while other large studies have found the association across a broader range of infection severity, so the precise picture of who's most affected is still being refined.

What about children and type 1 diabetes?

This is a more contested area of research. A study covering data from 14 nations found children and adolescents faced a 72% increased risk of developing type 1 diabetes in the six months following COVID-19 infection. However, a separate Scottish study concluded the virus likely wasn't the direct cause of the pattern it observed, suggesting other factors, such as changes in healthcare-seeking behaviour or diagnosis patterns during the pandemic, might explain some of the apparent increase. This is a genuine area of ongoing scientific debate rather than a settled conclusion.

How researchers think COVID-19 might trigger diabetes

Several mechanisms have been proposed, though none is definitively confirmed as the primary explanation. These include direct viral damage to insulin-producing cells in the pancreas, the metabolic stress and inflammation caused by severe illness and the possibility that COVID-19 unmasks or accelerates diabetes that was already developing but not yet diagnosed. It's likely that more than one of these mechanisms plays a role and research continues into which matters most and for which groups of people.

Does this apply to mild infections too?

Some of the research suggesting an increased risk has included people with a broad range of infection severity, not just those hospitalised, though the strength of the association does appear to vary. This is part of why the topic remains an active area of research rather than a fully settled question and why some studies conclude the risk is concentrated among more severe cases while others find it across a wider population.

What symptoms of diabetes to watch for

Common early symptoms of diabetes include increased thirst, needing to urinate more often, particularly at night, unexplained tiredness, unintended weight loss and blurred vision. If you've had COVID-19 and notice any of these symptoms developing afterwards, particularly within the following months, mentioning this to your GP and requesting a blood sugar check is a sensible, low-cost step given what the research has found.

What you can do

There's no specific test recommended for everyone who's had COVID-19 to screen for diabetes, but being aware of the symptoms and not dismissing them as unrelated tiredness or general post-viral fatigue is worthwhile. General measures that reduce diabetes risk more broadly, maintaining a healthy weight, staying physically active and eating a balanced diet, remain relevant regardless of COVID-19 history and are worth prioritising as part of your overall recovery.

Recognising the warning signs

The NHS diabetes symptoms page lists the key signs to watch for, including excessive thirst, frequent urination and unexplained fatigue. Given the research linking COVID-19 to elevated diabetes risk, it's worth being a little more alert to these symptoms specifically in the months following an infection, rather than assuming ongoing tiredness is simply a normal part of recovery.

Why researchers continue to study this link

Diabetes is a lifelong condition with significant health implications, so establishing whether and how strongly COVID-19 contributes to new cases matters for public health planning as much as for individual patients. Large-scale studies covering tens of millions of people, combined with more detailed mechanistic research into how the virus might affect insulin-producing cells, continue to refine understanding of exactly how strong this link is and which groups face the greatest risk.

Talking to your GP about your risk

If you're concerned about your personal diabetes risk following COVID-19, a simple conversation with your GP about a blood sugar test is a reasonable step, particularly if you have other risk factors such as being overweight, having a family history of diabetes or being over 40. Early detection generally leads to better outcomes, whether or not COVID-19 turns out to have played a role in your specific case.

Whatever the eventual scientific consensus turns out to be, paying attention to your own body and seeking a straightforward blood test if something feels persistently off remains sound, low-risk advice regardless of the underlying cause.

A quick recap

Multiple large studies, covering tens of millions of people between them, have found a consistent link between COVID-19 infection and an increased risk of new-onset diabetes, generally in the region of 40 to 66% higher risk depending on the specific study and population. The picture for children and type 1 diabetes is less settled, with some research pointing to increased risk and other research questioning a direct causal link. If you've had COVID-19 and develop symptoms suggestive of diabetes, raising it with your GP is a reasonable precaution.

Frequently asked questions

How soon after COVID-19 does diabetes risk appear?

Research has found the increased risk tends to be most pronounced in the months immediately following infection, though studies have tracked outcomes for a year or more afterwards and continued to find an elevated risk.

Is type 1 or type 2 diabetes more linked to COVID-19?

Most of the strongest evidence in adults points to type 2 diabetes. The link to type 1 diabetes, particularly in children, is a more actively debated area with mixed findings between different research groups.

Does vaccination reduce diabetes risk after COVID-19?

This hasn't been extensively studied as a specific outcome, though vaccination's established role in reducing the risk of severe illness generally would plausibly reduce exposure to some of the more severe-illness-associated pathways researchers believe may contribute to diabetes risk.

Should everyone who's had COVID-19 get tested for diabetes?

Routine testing isn't currently recommended for everyone. Being alert to diabetes symptoms and seeking a GP assessment if they appear is the more commonly recommended approach.

Can diabetes caused by COVID-19 go away?

This varies by individual and the type of diabetes involved. Some people diagnosed with high blood sugar during acute illness see it resolve afterwards, while others go on to develop a persistent diabetes diagnosis requiring ongoing management.