A major row has erupted over conflict of interest claims involving a study linking negative news stories about statins with an increased risk of heart attacks and death.
One of the study's two authors, Danish scientist Professor Borge Nordestgaard, has admitted receiving consultancy fees and lecture payments from a host of drug companies.
Among them are AstraZeneca, Pfizer and Merck - all major producers of the cholesterol-lowering drugs taken by millions of people in the UK.
The disclosure, made in a brief conflict of interest statement at the end of the research paper, prompted a withering response from a doctors' leader.
Dr Kailash Chand, deputy chairman of the British Medical Association (BMA), said: "We need doctors to concentrate on research that matters to patients, not their careers or the advance of drug companies.
"The existence of a conflict of interest tends to create the appearance of bias even if the person with the conflict of interest acts completely impartially. In this study, the bias is very apparent."
Dr Chand, who was representing his own views and not those of the BMA, is an outspoken critic of what he regards as industry-driven hype surrounding statins.
The study is reported in the European Heart Journal, a highly respected publication, and was independently funded.
It is based on an analysis of data from 674,000 Danes aged 40 and over who were using statins between January 1995 and December 2010.
Their progress was followed until the end of 2011 and compared with trends in media coverage relating to statins.
The authors found a correlation between negative news stories about the medicines and people stopping their statin treatment within six months of a first prescription.
This in turn was associated a higher risk of heart attacks and deaths from cardiovascular disease.
Over the period of the study, 110 negative, 1,090 neutral and 731 positive stories about statins published or broadcast nationally in Denmark were identified.
For every negative story published or broadcast in Denmark, the risk of patients halting their treatment increased by 9%, said the researchers.
Prof Nordestgaard, chief physician at Copenhagen University Hospital, said: "We found that exposure to negative news stories about statins was linked to stopping statins early and explained 2% of all heart attacks and 1% of all deaths from cardiovascular disease associated with early discontinuation of statins.
"People who stop statins early have a 26% increased risk of a heart attack and an 18% increased risk of dying from cardiovascular disease when compared to people who continue to use them.
"Although we cannot say for sure that statin-related negative news stories cause the early discontinuation of statins, our findings suggest that this is likely. And although this type of association research cannot prove causality, our data suggest that early discontinuation of statins leads to unnecessary heart attacks and deaths from cardiovascular disease."
Statins are considered to be generally safe but can cause side effects in some patients including muscle pains and, rarely, a serious condition called rhabdomyolysis which destroys muscle fibres.
In England and Wales, any healthy person with a 20% or greater risk of developing cardiovascular disease over 10 years is eligible to have statins on the NHS.
The other author who carried out the work with Prof Nordestgaard was Dr Sune Nielson, also from Copenhagen University Hospital.
Both made an obligatory conflict of interest statement at the end of the study. In relation to Dr Nielson, there were said to be "no financial or other conflicts of interest".
However, Prof Nordestgaard owned up to having received "consultancy fees and /or lecture honoraries" from the following companies: AstraZeneca, Pfizer, Merck, Amgen, Sanofi, Regeneron, Omthera, Dezima, ISIS Pharmaceuticals, Aegerion, Fresenius, B. Braun, Kaneka, Lilly, Kowa and Denka Seiden.
Dr Chand argued that in his view the conclusions of the study were "very misleading" and detracted from the real issues surrounding statins - lack of transparency over the drugs' side effects and the fact that their benefits have been "grossly exaggerated".
He added: "This is a witch hunt, it is not science. It is an attempt to crush debate and it should not be allowed."
Making a general comment about conflict of interest, he declared: "Medical research is fraught with incompetence, careerism and fraud. Conflict of interest ... is a cancer eating at the core of medical research.
"The more embedded the financial and other interests in the outcome of a study, the more likely the findings are going to be false."
Other experts said the study showed both strengths and weaknesses.
Professor Stephen Evans, from the London School of Hygiene & Tropical Medicine, said: "Being certain that it is the media stories that cause discontinuation requires some assumptions, though they are reasonable."
He added: "The message from the paper should be listened to by journalists and the media as well as by patients. The media need to be responsible in their use of scare stories - they may affect patients' health."
Professor Peter Weissberg, medical director of the British Heart Foundation, said: "This interesting study raises important questions about how people make decisions that affect their health and the consequences of those decisions.
"It is important for patients that their doctors base their advice on objective interpretation of the best evidence available rather than biased reports in the lay and medical press."
Prof Nordestgaard refuted any suggestion of bias, and pointed out that most statins were now off-patent and made by generic medicine companies that he had "nothing to do with".
He told the Press Association: "I might as well have written that I had no conflict of interest.
"If companies ask me on advisory boards to talk about different issues to do with the development of new drugs I do that because it's scientifically interesting, but I don't go into any of the marketing side of things.
"I have one huge conflict of interest and that is the Danish tax payer. That's the biggest by far."
He added: "Personally, I would never do anything a company wanted me to do. I say exactly what I think based on scientific evidence."