A common stomach bug may increase the risk of developing Alzheimer's disease, according to a new study. Researchers at McGill University in Montreal analysed health records of four million Britons aged 50 and above between 1988 and 2019.
They found that people with symptomatic Helicobacter pylori infection had an 11 per cent higher risk of developing Alzheimer's disease. The risk peaked at 24 per cent between seven and 10 years after infection before declining.
Helicobacter pylori is a bacterium found in contaminated food, water and soil, and can be passed via bodily fluids. Around 40 per cent of people in the UK carry it, but only about 15 per cent develop symptoms such as indigestion, gastritis, ulcers, or stomach cancer.
The researchers suggested the bacterium may travel to the brain, causing inflammation and neurodegeneration. It may also disrupt gut balance, leading to overproduction of amyloid protein, which forms plaques in Alzheimer's patients. Damage to the stomach lining could impair absorption of vitamin B12 and iron, both linked to dementia.
Dr Paul Brassard, senior author and professor at McGill, said: 'Given the global ageing population, dementia numbers are expected to triple in the next 40 years. However, there remains a lack of effective treatment options for this disease.' He added that eradicating the bug could help prevent about 200,000 cases of Alzheimer's globally each year.
The study was published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.
