Without cholesterol our body could not exist. The substance serves as a building material of our cells, forms the skeleton of many hormones and promotes the digestion of fats as a forerunner of the bile acid. Too much cholesterol, however, that is undisputed, deposits on the wall of the blood vessels, thereby increasing the risk of heart attack and stroke.
For decades, doctors have been using cholesterol-lowering drugs called statins to reduce the risk of cardiovascular disease. They prescribe these when a high cholesterol patient is already suffering from a cardiovascular disease, or is in danger of dying from it within the next ten years. However, a recent study shows that many more people could benefit from the funds.
Thus, especially in people under the age of 45, elevated cholesterol significantly affects the risk of developing severe cardiovascular disease later in life. The ten-year risk, the doctors used in their decision for or against drugs, is often too short, is the conclusion of the study in the journal "The Lancet".
The base: data from 400,000 people from 19 countries
For the investigation, a team led by Fabian Brunner from the University Heart & Vascular Center Hamburg evaluated data from almost 400,000 people, most of whom came from Europe. At the beginning of the study, the subjects were on average 51 years old and had no heart disease. However, in the following years - on average, there were 13 - but 54,000 were suffering from heart and vessels.
In the first step, scientists combined these numbers with the participants' cholesterol levels. They used the so-called non-HDL cholesterol value, which includes all forms of cholesterol - apart from HDL cholesterol. The HDL has the important function in the body to transport cholesterol from the tissues (such as the cell walls) to the liver, and there, for example, to convert it into bile acids.
The results showed a clear correlation between cholesterol levels at baseline and the likelihood of later disease. In both men and women, the probability of developing cardiovascular disease within the next 30 years was three to four times higher in the group with the highest cholesterol levels than in the group with the lowest cholesterol levels.
Risk greatly increased at the age of 45 years with high cholesterol
Another surprising finding: among those under 45, cholesterol levels had the greatest impact on disease risk. This was especially true when the researchers considered a longer period than just ten years.
Who paid for it?
The study was funded by independent institutions: a research funding program of the European Commission, the UK Medical Research Council and the German Center for Cardiovascular Research. However, some of the 40 study authors have received fees from pharmaceutical companies, as is common in medical research.
In a second step , the scientists calculated for different age groups the risk of falling ill in the course of their life. For example, according to the results:
- A healthy, overweight smoker under the age of 45, with slightly elevated cholesterol, has a 16 percent chance of getting her 75th birthday.
- In a still healthy overweight smoker from 60 with the same conditions, the risk is therefore only 12 percent.
This is probably due to the fact that not only the level of cholesterol determines the risk of disease, but also the duration of the body's exposure to cholesterol. The only question is: should therefore all young adults with slightly elevated levels swallow cholesterol-lowering drugs for decades? How many people would really benefit from this?
The risk of young adults in detail
Women under 45, low cholesterol
Women under the age of 45 with the lowest cholesterol (non-HDL cholesterol below 2.6 mmol / liter) and with no or just one other risk factor for cardiovascular disease (eg, diabetes, obesity, or smoking) have a 5, 7% risk of developing cardiovascular disease by 75th birthday.
Women under 45, high cholesterol
In women under 45, who were in the highest cholesterol group (non-HDL cholesterol at least 5.7 mmol / l) and had at least two other risk factors, the value was almost four times higher at 24.1 percent .
Men under 45, low cholesterol
Men under the age of 45 years with the lowest cholesterol (non-HDL cholesterol below 2.6 mmol / L) and with no or just one other risk factor for cardiovascular disease (such as diabetes, obesity or smoking) have 11, 8% risk of developing cardiovascular disease by 75th birthday.
Men under 45, high cholesterol
In men under the age of 45, who were in the highest cholesterol group (non-HDL cholesterol at least 5.7 mmol / l) and had at least two other risk factors, the figure was almost four times as high at 43 percent . It has long been known that elevated cholesterol levels have a stronger effect on men.
Decades of therapy
In a third step , the researchers calculated how much young adults will benefit if their cholesterol value is permanently halved. This is not possible with a balanced diet alone.
- Statistically, approximately eight women with a slightly elevated cholesterol level would have to take medications for over 30 years to avoid serious cardiovascular disease until their 75th birthday. However, this only applies to people who still have at least two other risk factors for cardiovascular diseases, such as smoking or being overweight.
- According to the calculations, in persons with only one or no other risk factors, almost 15 people would have to take medication for 30 years to prevent a disease. The benefit of taking statins is therefore undoubted for larger risk factors.
However, the numbers are statistical extrapolations - in clinical studies, patients have never taken cholesterol-lowering drugs for such a long time. For this reason, it is also unclear whether there may be unknown side effects over decades. This must be clarified further studies in the future.
By themselves, statins are considered to be well tolerated and they are cheap. However, sometimes the remedies may increase blood sugar and rarely cause muscle pain. Even rarer they lead to a dangerous decomposition of the muscles.
It will not work with the diet alone
Despite the limitations, scientists who did not participate in the study rate the results as extremely valuable: "Everyone knows that high cholesterol levels are associated with a higher risk of heart attack or stroke," said Paul Leeson, professor of cardiovascular medicine at the University of California University of Oxford's study the "Science Media Center". "What has been shown for the first time, however, is that high cholesterol levels in people under the age of 45 disproportionately increase the risk of problems later in life."
However, according to Leeson, it is still too early to revise the treatment recommendations based on the data. Previously, studies would have to clarify how the cholesterol levels in young people could be lowered and whether it was really necessary for decades to swallow medication, he says. One of such risk-benefit considerations is to check the possible side effects.
Jane Armitage, from the University of Oxford, also sees the study as another important piece of evidence that treatment for high cholesterol in younger years protects against heart attacks and strokes later in life. But she sees a very different difficulty: "The challenge is to get people to take medication for many years." Especially if they do not feel anything of the impending illness.
What can affected people do anyway? Consume as little as possible saturated fatty acids from cheese, meat or chocolate and instead rely on unsaturated fatty acids, whole grains and legumes.
