Common Gene Variant May Delay Diabetes Diagnosis in Millions of Men, Study Warns

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New Delhi, Sept 30 — A common genetic condition known as glucose-6-phosphate dehydrogenase (G6PD) deficiency may be delaying the diagnosis of type 2 diabetes in millions of men worldwide, according to new research published in Diabetes Care. The study, led by scientists from the University of Exeter and Queen Mary University of London (QMUL), highlights serious concerns about the global reliance on the HbA1c blood test — the gold standard for diagnosing diabetes — which may provide misleading results in men with this genetic variant.

Researchers found that men living with G6PD deficiency are often diagnosed with type 2 diabetes an average of four years later than those without the condition, significantly raising their risk of long-term health complications.

What the Study Found

The study analyzed health data from large, diverse population groups and found two key issues:

Delayed diagnosis: Men with G6PD deficiency had a lag of about four years in receiving a diabetes diagnosis compared to men without the condition.
Higher complication risks: Once diagnosed, these men faced a 37% increased risk of serious diabetes-related complications, including damage to the eyes (retinopathy), kidneys (nephropathy), and peripheral nerves (neuropathy).

The underlying reason for this delay lies in how HbA1c testing works. The HbA1c test measures the average blood glucose over 2–3 months by examining how much glucose has bonded to hemoglobin in red blood cells. But in people with G6PD deficiency, the lifespan of red blood cells is shorter, artificially lowering HbA1c levels. This gives the false impression that blood sugar is within a healthy range.

“Doctors and policymakers need to be aware that HbA1c is not always reliable in certain genetic groups,” said Professor Inês Barroso of the University of Exeter. “Routine G6PD screening in high-prevalence populations could improve health outcomes by ensuring timely diagnosis and treatment.”

What is G6PD Deficiency?

G6PD deficiency is one of the world’s most common inherited metabolic conditions, affecting more than 400 million people globally. It is caused by mutations in the G6PD gene, which reduces the activity of an enzyme needed to protect red blood cells from damage.

Prevalence: The condition is particularly common among populations of African, Asian, Middle Eastern, and Mediterranean descent.
Symptoms: Many people remain unaware they have the condition, as it may present no symptoms or only mild issues, such as anemia triggered by certain foods, infections, or medications.
Gender bias: Because the G6PD gene sits on the X chromosome, males are more often affected, while females are more likely to be carriers.

The World Health Organization (WHO) recommends routine screening in areas of high prevalence, but in practice, the condition remains underdiagnosed and under-tested.

Why This Matters for Diabetes Diagnosis

Globally, the number of people living with diabetes has quadrupled over the past three decades, making it one of the most pressing public health concerns of the century. Early diagnosis is critical, as delayed detection allows persistently high blood sugar to silently damage vital organs.

The HbA1c blood test has been the international standard for diagnosing and monitoring diabetes in at least 136 countries. Its widespread use is due to convenience (it doesn’t require fasting), consistency, and cost-effectiveness. But for individuals with G6PD deficiency, HbA1c may not tell the full story.

“This issue underscores the danger of a ‘one-size-fits-all’ approach in global diabetes diagnostics,” said Dr. Ruchi Sood, a Delhi-based endocrinologist not involved in the study. “Relying solely on HbA1c in these genetic populations risks missing diabetes in its earliest — and most treatable — stages.”

Implications for Public Health

The study brings to light an urgent need for tailored healthcare policies in regions where G6PD deficiency is common. Public health experts warn that without alternative diagnostic strategies, millions may continue to slip through the cracks, unknowingly living with undiagnosed diabetes until complications arise.

Potential solutions include:

Routine G6PD screening in at-risk populations before diabetes testing.
Greater reliance on fasting plasma glucose (FPG) and oral glucose tolerance tests (OGTT), which are unaffected by G6PD deficiency.
Public awareness campaigns in high-prevalence regions to encourage testing and early lifestyle interventions.

“Health equity is at stake here,” noted Professor Barroso. “We must ensure diagnostic accuracy for everyone, regardless of genetic background, to prevent unnecessary suffering and costly long-term complications.”

Limitations and Ongoing Questions

While the findings are compelling, experts caution that further research is needed to strengthen the evidence. Some limitations include:

The study focused primarily on men, leaving open questions about the diagnostic implications for women, especially carriers of the gene.
Access to comprehensive diagnostic infrastructure, particularly in low- and middle-income countries, may limit real-world implementation of alternative testing protocols.
More research is needed to assess the cost-effectiveness of routine G6PD screening at a population level.

Nonetheless, the findings open new conversations about personalized medicine and the need for diagnostic tools that account for genetic diversity in global populations.

What This Means for Readers

For individuals, especially men of African, Mediterranean, Middle Eastern, or South Asian heritage, these findings serve as a reminder that standard blood tests may not always tell the whole story. If you fall into one of these groups and have risk factors for diabetes (such as obesity, family history, or high blood pressure), it may be worthwhile to ask your doctor about additional testing beyond HbA1c.

Lifestyle choices — such as maintaining a healthy diet, exercising regularly, and avoiding smoking — remain the cornerstone of diabetes prevention. But timely and accurate diagnosis makes the difference between living years with silent, undetected disease and taking action early to prevent complications.

Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.