US health authorities have issued an alert urging people to stop using specific models of Abbott Diabetes Care’s glucose monitoring sensors after the company linked the devices to seven deaths and hundreds of serious injuries around the world.

The US Food and Drug Administration (FDA) said this week that select batches of the FreeStyle Libre 3 and FreeStyle Libre 3 Plus sensors may report falsely low glucose readings. Incorrect readings over time can prompt people with diabetes to make unsafe treatment choices, including taking excessive carbohydrates or delaying necessary insulin doses.

In its notice, the FDA said such decisions could pose major health risks and may lead to severe injury or death.

The sensors track glucose in the fluid beneath the skin, providing continuous updates that are transmitted to a user’s phone or reader. Abbott said the alert covers around three million sensors distributed in the United States, all from a single production line. Around half of those units have either been used or are past their expiry date.

FreeStyle Libre 3 was approved for use in Europe in 2020, and the sensors are sold in several major markets including Germany, Spain, Italy, France, the Netherlands and the UK. As of 14 November, Abbott reported seven deaths and 736 serious incidents tied to the affected sensors worldwide.

The company said it has contacted all customers and healthcare partners about the issue and confirmed that it has identified and corrected the fault in the production batch linked to the problem.

The FDA is advising users to dispose of affected sensors immediately. Impacted devices include FreeStyle Libre 3 sensors with model number 72080-01 and unique device identifiers 00357599818005 and 00357599819002. The alert also covers FreeStyle Libre 3 Plus sensors with model numbers 78768-01 and 78769-01 with identifiers 00357599844011 and 00357599843014.

Abbott has directed consumers to a dedicated website, FreeStyleCheck.com, where they can check whether their device is part of the affected lot and request a replacement at no charge. The company stressed that no other FreeStyle Libre products are involved in the warning.

Regulators said the alert will remain in place until they are satisfied that all potentially problematic sensors have been removed from circulation and replaced with updated units.

A new analysis presented in the United States suggests that routine blood tests could play a greater role in tracking Alzheimer’s disease, particularly among people living with obesity. The research, conducted by scientists at Washington University School of Medicine in St. Louis, indicates that obesity may accelerate the early biological changes associated with the condition.

The study, which will be shared at the annual meeting of the Radiological Society of North America, examined 407 adults over a five-year period. Participants underwent regular blood tests and PET scans, the latter measuring the buildup of amyloid plaques in the brain — a hallmark of Alzheimer’s disease. The blood tests assessed proteins and other biomarkers that are linked to cognitive decline.

Dr. Cyrus Raji, associate professor of radiology and neurology and one of the study’s authors, said this research marks the first time a clear relationship has been identified between obesity and Alzheimer’s progression using blood biomarker tests. He noted that blood results were able to detect obesity’s influence on Alzheimer’s-related changes more precisely than PET scans alone.

“The fact that we can track the predictive influence of obesity on rising blood biomarkers more sensitively than PET is what astonished me in this study,” Raji said.

According to the findings, people with obesity showed faster deterioration in several key biomarkers. The researchers reported a 24 per cent faster increase in the protein plasma NfL, which is associated with nerve damage. Levels of the blood biomarker plasma pTau217 rose 29 to 95 per cent faster in individuals with obesity, and amyloid plaque accumulation increased by 3.7 per cent.

Raji said these results may give doctors new ways to monitor how Alzheimer’s develops, especially as new treatments targeting amyloid buildup become more common. By using both blood tests and imaging, doctors may be able to gain a clearer picture of how the disease responds to medication.

“It’s marvellous that we have these blood biomarkers to track the molecular pathology of Alzheimer’s disease, and MRI scans to track additional evidence of brain degeneration and response to various treatments,” he noted.

Obesity has long been recognised as a risk factor for dementia. Individuals with obesity are more likely to experience conditions such as high blood pressure, type 2 diabetes, and reduced physical activity, all of which heighten the risk of cognitive decline.

Globally, around 57 million people are living with dementia, according to the World Health Organization. Alzheimer’s disease represents the largest share, accounting for between 60 and 70 per cent of all cases.