High blood sugar 'weakens immunity in type 2 diabetes'

Cheng Wong

Researchers at the University of Hong Kong have discovered that high blood sugar levels significantly weaken the immune response of patients with type 2 diabetes, or T2D, against viral infections.

T2D is prevalent in Hong Kong, affecting about 70,000 people - one-tenth of the city's population of 7.5 million.

Many T2D patients struggle to maintain their blood sugar levels within a healthy range, making them more susceptible to severe health risks.

Those with poorly controlled T2D typically have HbA1c levels - average blood sugar levels over the past two to three months - exceeding 8 percent, which is well above the ideal target of 6.5 percent or lower.

During the Covid-19 pandemic, the mortality risk for T2D patients was three times higher than for those without the condition.

To investigate the underlying mechanisms, the HKUMed research team analyzed 40 blood samples from T2D patients at Queen Mary Hospital between 2022 and 2023.

They found that elevated blood sugar levels degrade T Helper 1 cells - crucial anti-viral cells - reducing the body's ability to respond effectively to viruses and other pathogens.

This impairment may also trigger a chronic inflammatory response, further compromising the immune system and heightening the risk of various health complications.

"These findings underscore the importance of maintaining blood glucose levels under control," said Heidi Ling Guang-sheng, an assistant professor from the School of Biomedical Sciences at HKUMed and a corresponding author of the study.

"A robust immune system is vital for alleviating healthcare burdens during viral pandemics and safeguarding lives."

Kwok Ka, a T2D patient for over 10 years, initially struggled to manage his blood sugar levels and experienced severe symptoms during the Covid-19 pandemic in 2022.

"While my family members [without T2D] had only mild symptoms, I faced serious difficulties. I couldn't breathe, felt extremely fatigued, and struggled to keep my eyes open. I had to be taken to the hospital by ambulance," he recalled.

However, after successfully controlling his blood sugar levels and reducing his HbA1c to around 7 percent, Kwok has not contracted Covid-19 since and has seen a significant reduction in many previous minor ailments.

Paul Lee Chi-ho, a clinical associate professor from the School of Clinical Medicine at HKUMed and another corresponding author, emphasized the importance of glycemic control for T2D patients.

"Understanding their HbA1c levels, adhering to their medication regimen and maintaining a healthy lifestyle are crucial. These measures are the most effective ways to manage blood sugar levels and protect against serious comorbidities and infections."

cheng.wong@singtaonewscorp.com