Undiagnosed Genetic Condition Delays Diabetes Diagnosis in Black and Asian Men

A significant yet commonly overlooked genetic disorder may be contributing to delays in the diagnosis of type 2 diabetes among Black and South Asian men in the UK, increasing their risk of severe health complications.

A recent study from the University of Exeter, conducted in partnership with Queen Mary University of London, revealed that approximately one in seven Black men and one in 63 South Asian men carry a genetic variant called G6PD deficiency. This deficiency is linked to a delayed diagnosis of type 2 diabetes, with affected individuals diagnosed an average of four years later than those without the variant. Alarmingly, fewer than 2% of those with the deficiency have received a diabetes diagnosis.

The research, published in the journal Diabetes Care, indicates that while G6PD deficiency does not directly cause diabetes, it impacts the reliability of the HbA1c blood test, which is widely used to diagnose and manage diabetes. This deficiency can lead to inaccurately low HbA1c results, complicating the diagnosis process and delaying necessary treatment.

Inês Barroso, a professor at the University of Exeter, emphasized the urgent need to revise testing protocols to address these health disparities. She noted that doctors and health policymakers should recognize the limitations of the HbA1c test for individuals with G6PD deficiency and consider routine screening for this genetic condition as a preventive measure.

Worldwide, G6PD deficiency affects over 400 million people, particularly those of African, Asian, Middle Eastern, and Mediterranean descent. The condition predominantly affects men and often goes undetected due to a lack of symptoms. Although the World Health Organization recommends routine screening in populations where G6PD deficiency is prevalent, such practices are not widely adopted in the UK or elsewhere.

The study's findings suggest that men with G6PD deficiency are 37% more likely to develop diabetes-related complications, such as damage to the eyes, kidneys, and nerves, compared to their counterparts without the deficiency. The HbA1c test, considered the gold standard for diabetes diagnosis in 136 countries, may underestimate blood sugar levels in individuals with G6PD deficiency, leading to significant medical delays and an increased risk of severe complications.

Dr. Veline L'Esperance, a general practitioner and Senior Clinical Research Fellow at Queen Mary University of London, expressed concern over the implications of these findings, highlighting the potential failures of a commonly used diagnostic tool in communities that are already disproportionately affected by diabetes. She advocated for heightened awareness among healthcare professionals and stronger policies to ensure equitable screening and diagnosis.

Professor Faye Ruddock, Chair of the Caribbean and African Health Network, acknowledged the existing health inequalities faced by Black communities in the UK regarding type 2 diabetes. She pointed out that stigma, language barriers, and cultural differences, along with limited health checks and screening opportunities in predominantly Black areas, contribute to these disparities. Ruddock called for the implementation of preventative measures to ensure timely diagnoses for Black individuals, especially men.

Anna Morris, Assistant Director of Research at Diabetes UK, emphasized that Black and South Asian individuals in the UK are twice as likely to be living with undiagnosed type 2 diabetes compared to white individuals and experience worse health outcomes once diagnosed. She underscored the need for accurate diagnostic tools that can serve all ethnicities effectively to prevent further compounding of existing health disparities.

Dr. Esther Mukuka, Director of Research Inclusion at the National Institute for Health Research (NIHR), affirmed the commitment to ensuring that research leads to fairer healthcare for all. Addressing the effects of G6PD deficiency on diabetes testing is a critical step toward reducing inequalities and ensuring equitable access to medical advancements.

The study analyzed genetic and health data from over 500,000 participants in the UK Biobank and Genes & Health studies, revealing that men with the G6PD deficiency genetic variant were diagnosed with diabetes at older ages compared to those without the condition. Furthermore, those with both G6PD deficiency and diabetes experienced more complications. Researchers advocate for further studies in diverse populations to validate these findings globally.