Researchers did not examine over-the-counter PPIs or particular brands of prescription-strength drugs. Instead, the team focused on prescription PPIs typically used at higher doses and for longer durations, CNN reported.

According to senior author Ziyad Al-Aly, for every 500 patients taking PPIs for one year, there would be one additional death that wouldn’t have occurred if the patient wasn’t using PPIs.

And with millions of people using PPIs on a daily basis to treat heartburn and stomach acid, thousands of additional deaths could result.

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Al-Aly and his team also found that the longer a patient used PPIs, the higher their risk of premature death.

Though the precise biological reason for a possible link between PPIs and risk of premature death is unclear, the gene-changing effect of the drugs may contribute to the potential problem.

Because the research is based on observational study, the team noted the findings are “far from conclusive,” meaning they do not prove cause and effect.

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But the findings "may be used to encourage and promote pharmacovigilance [monitoring the side-effects of licensed drugs]," the authors wrote, urging patients to be judicious in their use of PPIs and limit the duration of use unless there is a clear medical benefit that outweighs any potential risk.

It's not the first time PPIs have been linked to some dangerous health trends. Previous research has also shown links between the drugs and dementia, cardiovascular disease, hip fractures and more.

Read the full study.