India is the top country globally to get low-quality research published in 'predatory' journals, according to a study which found that it contributed 27 per cent of the scientific studies in bogus publications.

The investigation, published in the journal Nature, also showed that majority of papers in suspected biomedical predatory journals (57 per cent) are from high or upper middle income countries, with many coming from prestigious institutions including the Harvard University in the US.

Largely unknown a decade ago, there are now an estimated 8,000 predatory journals collectively publishing more than 400,000 research studies each year.

These journals offer to quickly publish research findings, typically at a lower cost than legitimate journals, but do not provide quality controls such as peer-review.

Predatory journals are also difficult to search, meaning that health-care providers and researchers can rarely learn from the data in these journals.

Researchers from The Ottawa Hospital and the University of Ottawa in Canada analysed 1,907 research papers published in 220 suspected biomedical predatory journals.

The journals were randomly selected from well-known but controversial lists compiled by University of Colorado librarian Jeffrey Beall.

Researchers found that the top countries publishing in these journals were India (27 per cent), the US (15 per cent), Nigeria (five per cent), Iran (four per cent) and Japan (four per cent).

The US Institutes of Health was the most frequent funder mentioned among the very few articles that credited one.

"Our research debunks the common belief that predatory journals are only a problem in low income countries," said David Moher, a senior scientist at The Ottawa Hospital and associate professor at the University of Ottawa.

"Predatory journals publish research from scientists around the world, including those based at prestigious high income institutions," said Moher.

The researchers also attempted to judge the quality of the suspected predatory journal papers using adapted versions of widely accepted reporting guideline checklists.

"While quality can be patchy even in legitimate journals, we found that it was far worse in suspected predatory journals," said Larissa Shamseer, a PhD student at The Ottawa Hospital and the University of Ottawa.

"For example, clinical trials published in predatory journals are much less likely to provide information on research ethics approval, trial registration and randomisation into treatment groups. These details are essential for other researchers to be able to gauge the validity of the results," said Shamseer.

"We estimate that data from millions of patients and animals may be tucked away in predatory journals," said Manoj Lalu, associate scientist at The Ottawa Hospital.

"Most of this work is undetectable by readers, including by health-care providers looking for research to inform patient care," said Lalu, assistant professor at the University of Ottawa.

The researchers also made a list of the top institutions publishing in their sample of suspected predatory journals and attempted to contact the corresponding authors.

Of 87 emails sent, 18 were responded to. Only two of the authors said they were aware that the journal they published in was potentially predatory.

Manipal University, which had 15 papers published in predatory journals, detailed an intervention launched earlier this year, and provided data that the effort reduced the number of articles published in presumed predatory journals, according to the researchers.