Where do such claims come from?
The Facebook post claims that low total cholesterol levels can by themselves cause or significantly increase the risk of many different health disorders – from mental and neurological diseases to heart, kidney diseases, infections, birth defects, and cancer.
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Some of the listed associations have indeed been recorded in scientific studies, but a crucial point is omitted here – a statistical correlation does not mean that low cholesterol is the cause of the disease.
In most cases, scientists talk about so-called reverse causality: it is not the lowered cholesterol that causes the disease, but the disease itself or the changes it causes in the body that can reduce cholesterol levels in the blood.
Low cholesterol does not cause cancer
There were indeed suspicions earlier that very low cholesterol levels might increase cancer risk. Some observational studies noted that people with lower LDL cholesterol levels were diagnosed with cancer more often.
However, such an association does not mean that low cholesterol caused the disease. One main explanation is reverse causality: an undiagnosed tumor itself can reduce cholesterol levels in the blood.
Much more about causality is revealed by randomized clinical trials where cholesterol levels are deliberately lowered with medication.
This issue was thoroughly examined by the international Cholesterol Treatment Trialists’ Collaboration (CTT) – a group of scientists summarizing cholesterol-lowering treatment studies.
In their meta-analysis, 27 statin clinical trials and data from about 175,000 people were evaluated. Over an average of five years of follow-up, more than 10,000 new cancer cases and over 3,500 cancer deaths were recorded.
The results were clear: lowering LDL cholesterol with statins did not increase cancer diagnoses, nor did cancer mortality increase. The relative risk was 1.00 – in simple terms, cancer risk was the same in treatment and control groups.
The researchers separately evaluated 23 different cancer localizations but found no increased risk for any of them. The results did not change with longer treatment duration, different statins, or different patient groups, including people over 75 years old.
It is especially important that cancer risk did not increase even in people whose LDL cholesterol was below 2 mmol/l before treatment. Lowering it further – on average from about 1.7 to 1.3 mmol/l – did not increase cancer cases.
Long-term follow-up of participants in the West of Scotland Coronary Prevention Study (WOSCOPS) found no increase in new cancer cases or cancer deaths among people initially treated with pravastatin.
Similar results were obtained in the Scandinavian Simvastatin Survival Study (4S). Over an average of 10.4 years of follow-up, cancer incidence and mortality did not differ significantly between groups initially receiving simvastatin or placebo.
In an even larger Heart Protection Study (HPS), more than 20,000 participants were followed for an average of 11 years. Here too, long-term LDL cholesterol lowering was not associated with increased overall or specific cancer risks.
Suspicions were dispelled
Manipulations falsely spreading online claim that lower cholesterol supposedly can provoke oncological diseases.
They are based on some scientific studies that indeed showed low total cholesterol more often in people later diagnosed with cancer. However, a more detailed analysis of the same data shows that this does not necessarily mean low cholesterol causes cancer.
The JPHC study conducted in Japan linked low total cholesterol with higher overall cancer and stomach cancer risk. However, when researchers excluded cancer cases diagnosed within the first three years of follow-up, this association weakened.
The study authors concluded that their results do not confirm that low cholesterol is the cause of most cancer types.
In an even larger South Korean study analyzing about 1.19 million adults, low total cholesterol was initially associated with higher cancer incidence.
However, after excluding liver cancer cases, this association significantly weakened.
The researchers noted this might be reverse causality: it is not low cholesterol increasing cancer risk, but liver disease or undiagnosed liver cancer reducing cholesterol levels in the blood.
Cholesterol and hormone imbalance
Scientists were concerned about very low cholesterol because it is indeed necessary for the body – some hormones are made from it, and it is important for cell membranes and other body functions.
Therefore, it was decided to find out whether drastically lowering cholesterol could disrupt hormone production or other metabolism.
However, clinical trials did not confirm such effects. In a study by Dirk J Blom and co-authors from the Lipidology Department of the University of Cape Town, 901 patients took the cholesterol-lowering drug evolocumab for one year.
LDL cholesterol decreased by about 60%, and for some patients reached very low levels – less than 15 mg/dl. Despite this, cortisol, testosterone, estradiol, and vitamin E concentrations did not decrease even in patients with the lowest LDL cholesterol.
Similar results were obtained in a smaller randomized trial with pravastatin. In 22 patients taking 40 mg of this statin daily, total and LDL cholesterol significantly decreased, but testosterone, estradiol, cortisol, and dehydroepiandrosterone sulfate (DHEAS) concentrations remained unchanged.
The researchers also found no hormonal changes indicating the body was trying to compensate for disrupted hormone production.
Depression, suicides, and violence
Some observational studies linked low cholesterol with depression, suicides, or violent behavior. However, such studies only show that these phenomena sometimes occur together – they do not prove that low cholesterol causes them.
This is also confirmed by a meta-analysis of statin trials. It found no evidence that cholesterol-lowering treatment increased deaths from suicides, accidents, or violence.
In the group taking statins, such deaths were even slightly fewer than in the control group, but the difference was too small to confidently attribute it to the treatment itself.
Heart failure
The claim that lowered cholesterol can harm the heart or even cause heart failure does not align with results from large randomized trials.
In 2015, a meta-analysis published in the European Heart Journal combined data from 17 large statin trials.
Altogether, more than 132,000 people were followed for an average of 4.3 years. During treatment, their LDL, or “bad,” cholesterol decreased by almost 1 mmol/l on average.
If cholesterol reduction itself increased heart failure risk, such large studies should show at least a clear signal of harm. However, the results showed the opposite trend. In the statin group, first hospitalizations for heart failure were 10% less frequent than in the control group – 1,344 cases among 66,238 people versus 1,498 cases among 66,330 control participants.
Considering hospitalizations and deaths from heart failure together, the risk was 8% lower. Mortality from heart failure alone did not change significantly – in other words, researchers found neither increased nor decreased risk. Meanwhile, the risk of non-fatal myocardial infarction was 26% lower in the statin group.
It is also important that similar results were found in all studies included in the meta-analysis, with no significant differences between them. Benefits were similar for people without prior cardiovascular disease and those at higher risk.
Longer follow-up data also do not show that harm would simply appear later. In the West of Scotland Coronary Prevention Study, with 15 years of follow-up, a 43% lower risk of hospitalization for heart failure was found among people previously treated with statins.
Alzheimer’s disease
Alzheimer’s disease is the most common cause of dementia – the gradual decline of memory, thinking, behavior, and social skills. It mostly affects people over 65 years old.
The fact-checking portal Health Feedback already debunked J. Wallach’s claims about Alzheimer’s disease last year. This was also covered by the 15min portal, as well as fact-checkers from Bosnia and Herzegovina and Taiwan.
Also read: Does cholesterol-lowering medication really cause Alzheimer’s disease?
The claim that Alzheimer’s disease is new and caused by low cholesterol levels is incorrect. It contradicts current scientific evidence about cholesterol’s influence on this disease.
Dementia cases have been recorded long ago. Since this disease is associated with aging, cases increased as human life expectancy grew.
A healthy person’s brain consists of tens of millions of neurons that process and transmit information via electrical and chemical signals.
They send messages between different brain parts and from the brain to muscles and organs. Alzheimer’s disease disrupts this neuronal connectivity, so neurons no longer function and die.
Although cholesterol is indeed important for the brain, most of it is produced by the brain itself, so blood cholesterol levels and brain cholesterol metabolism are not the same.
One of the most important studies on this topic is EBBINGHAUS (“Evaluating PCSK9 Binding Antibody Influence on Cognitive Health in High Cardiovascular Risk Subjects”), which assessed whether strong cholesterol lowering impairs cognitive functions. It was part of the larger FOURIER (“Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Subjects With Elevated Risk”) clinical trial.
Later, 473 EBBINGHAUS participants were followed for an average of 5.1 years, and some for up to 7.2 years from initial enrollment. Participants took statins and evolocumab – a drug inhibiting PCSK9 protein and thus strongly lowering LDL, or “bad,” cholesterol in the blood. During long-term follow-up, very low LDL cholesterol was not associated with cognitive decline.
15min verdict: false. The claim that low cholesterol by itself causes cancer, Alzheimer’s disease, depression, suicides, violent behavior, hormone disorders, or heart failure is misleading.
Some such associations were indeed observed in observational studies, but this does not prove causality – in some cases, the disease itself may reduce cholesterol levels in the blood.
Randomized clinical trials and large meta-analyses do not show that cholesterol lowering increases the risk of cancer, heart failure, or cognitive impairment.
On the contrary, statin trials showed reductions in heart attacks and hospitalizations for heart failure, and even very low LDL cholesterol was not linked to cognitive decline.
Publication prepared by 15min in cooperation with Meta, aiming to stop the spread of misleading news on social media. More about the program and its rules – here.
