Heart health may not have much to do with cholesterol levels.
In the case of good vs. bad cholesterol, things are less clear-cut than we'd like them to be.
An increasing number of studies suggest that high-density lipoprotein (HDL) cholesterol, or the "good" kind, may not be so good after all.
A recent study found an unsettling association between HDL cholesterol and mortality in men.
Another one found that HDL cholesterol levels correlated with a higher risk of heart disease among women.
Now, new research has shone a critical light on "bad," or low-density lipoprotein (LDL), cholesterol.
Researchers led by Dr. Uffe Ravnskov, Ph.D. — a former medical practitioner and independent researcher based in Lund, Sweden — set out to analyze the findings of three large reviews that maintain that LDL cholesterol gives rise to atherosclerosis and cardiovascular disease (CVD) and that statins prevent CVD.
The results were published in the journal Expert Review of Clinical Pharmacology.
Why high LDL cholesterol is not the culprit
Dr. Ravnskov and his team started with philosopher Karl Popper's criterion for the falsifiability of scientific claims, according to which a scientific theory can never be proven true, but it can be shown to be false. So, they set out to see if the bad cholesterol hypothesis could be falsified.
The hypothesis that high LDL cholesterol is the main cause of heart disease is invalid, explain the researchers, "because people with low levels become just as atherosclerotic as people with high levels and their risk of suffering from CVD is the same or higher."
"The usual argument in support of the lipid hypothesis," they continue, "is that numerous studies of young and middle-aged people have shown that high [total cholesterol] or LDL [cholesterol] predict future CVD."
"This is correct, but association is not the same as causation," write the scientists. Not only are the studies unable to prove causality, but the statistical methods are also flawed, they say.
Dr. Ravnskov and colleagues conclude:
"Our search for falsifications of the cholesterol hypothesis confirms that it is unable to satisfy any of the Bradford Hill criteria for causality, and that the conclusions of the [...] three reviews are based on misleading statistics, exclusion of unsuccessful trials, and by ignoring numerous contradictory observations."
People should make an informed decision
Study co-author Prof. David Diamond, of the University of Southern Florida in Tampa, comments on the findings, saying, "There have been decades of research designed to deceive the public and physicians into believing that LDL causes heart disease, when in fact, it doesn't."
"The research that has targeted LDL is terribly flawed," he goes on to explain. "Not only is there a lack of evidence of causal link between LDL and heart disease, the statistical approach statin advocates have used to demonstrate benefits has been deceptive."
The researchers aim "to share this information with people, so they can make an informed decision when they're considering taking cholesterol lowering medication."
In the paper, the authors disclose that Dr. Ravnskov — along with a few other co-authors — have previously published books that criticize the idea that LDL cholesterol causes heart disease.
Dr. Ravnskov is the director of The International Network of Cholesterol Skeptics, and in 2007, he was awarded the Leo-Huss-Walin Prize for Independent Thinking.