Pills millions take linked to significantly higher dementia risk

 A widely prescribed medication taken by millions across Britain could dramatically increase dementia risk, according to groundbreaking research. Scientists discovered that individuals using these tablets for longer than 4.4 years may have a 33% greater likelihood of developing dementia compared to those who had never taken the medication.

The 2023 research, featured in Neurology, the official publication of the American Academy of Neurology, examined 5,712 participants aged 45 and above who showed no signs of dementia when the study commenced. The average participant age was 75.

Researchers assessed whether subjects had used proton pump inhibitors (PPIs) - medications that decrease stomach acid production by targeting specific enzymes within the stomach's lining. Among those studied, 1,490 people, some 26%, had used these drugs.

The study group was subsequently categorised into four sections depending on their medication usage and duration: those who hadn't used the drugs; people who had taken them for up to 2.8 years; those using them between 2.8 and 4.4 years; and people who had taken them beyond 4.4 years.

Acid reflux occurs when stomach acid travels back into the oesophagus, typically following meals or whilst lying flat. Sufferers of acid reflux might experience heartburn and develop ulcers.

Those experiencing regular acid reflux could develop gastroesophageal reflux disease (GERD), which may progress to oesophageal cancer. "Proton pump inhibitors are a useful tool to help control acid reflux, however long-term use has been linked in previous studies to a higher risk of stroke, bone fractures and chronic kidney disease," said study author Kamakshi Lakshminarayan, MBBS, PhD, of the University of Minnesota School of Public Health in Minneapolis, and a member of the American Academy of Neurology.

"Still, some people take these drugs regularly, so we examined if they are linked to a higher risk of dementia. Whilst we did not find a link with short-term use, we did find a higher risk of dementia associated with long-term use of these drugs."

Participants were monitored for an average period of 5.5 years. During this time, dementia developed in 585 individuals, representing 10% of the group.

Out of the 4,222 participants who did not take the drugs, 415 developed dementia, equating to 19 cases per 1,000 person-years. Person-years account for both the number of people in the study and the duration each person spends in the study.

Of the 497 people who took the drugs for more than 4.4 years, 58 developed dementia, or 24 cases per 1,000 person years.

After adjusting for factors such as age, sex and race, as well as health-related factors like high blood pressure and diabetes, researchers discovered that those who had been taking acid reflux drugs for over 4.4 years had a 33% increased risk of developing dementia compared to those who never took the drugs.

The study did not identify an increased dementia risk for people who used the drugs for less than 4.4 years. However, it's crucial to note that this research does not establish a causal link between acid reflux medications and dementia; it merely indicates a correlation.

Lakshminarayan, one of the researchers, emphasised the need for further investigation: "More research is needed to confirm our findings and explore reasons for the possible link between long-term proton pump inhibitor use and a higher risk of dementia. Whilst there are various ways to treat acid reflux, such as taking antacids, maintaining a healthy weight, and avoiding late meals and certain foods, different approaches may not work for everyone.

"It is important that people taking these medications speak with their doctor before making any changes, to discuss the best treatment for them, and because stopping these drugs abruptly may result in worse symptoms."

One limitation of the study was the method of data collection on medication usage, which relied on annual self-reports from participants. This could have led to inaccuracies if participants had stopped and restarted their acid reflux medication between check-ins.

The researchers were also unable to determine if participants were using over-the-counter acid reflux drugs. The National Institutes of Health, including the National Heart, Lung, and Blood Institute, provided funding for the study.