In a study, led by scientists at Imperial College London, researchers analysed data from over 5,000 people taking part in cholesterol-lowering trials.They wanted to assess whether reducing cholesterol as low as possible is safe, and whether it was more beneficial than the current levels achieved with existing drugs.
‘LDL carries cholesterol to cells and deposits the excess in artery walls, which is a risk for heart attack. So, reducing LDL levels with combination therapy of statins and alirocumab reduces risk of heart disease.’
The scientists found that dropping cholesterol to the lowest level possible - to levels similar to those we were born with - reduced the risk of heart attack, stroke or fatal heart disease by around one third.
Professor Kausik Ray, lead author of the research from the School of Public Health at Imperial, said, "Experts have been uncertain whether very low cholesterol levels are harmful, or beneficial. This study suggests not only are they safe, but they also reduced risk of heart disease, heart attack and stroke."
In the paper, the scientists examined levels of low density lipoprotein (LDL) cholesterol or 'bad' cholesterol, as it is responsible for clogging arteries. LDL cholesterol maintained at 100 mg/dL or below is recommended safe.
The study analysed data from 10 trials involving 5,000 patients. All of the patients had previously been diagnosed with high cholesterol, and many were slightly overweight. The average age was 60, and the researchers tracked the patients for between three months and two years. The average cholesterol reading was around 125 mg/dL, and they were all deemed at risk of heart problems or stroke.
Over half the patients were on alirocumab, every two weeks via a small injection along with statin therapy. Alirocumab may be needed when patients' cholesterol levels are not sufficiently lowered by statins.
The combined effect of the new drug and the statin in the trials meant that patients reached very low cholesterol - lower than 50mg/dL. This is comparable to the levels we are born with, but is only achievable in adulthood through medication - lifestyle and exercise alone would not drop levels so low.
The researchers found lowering levels of cholesterol reduced the risk of heart attack, stroke, angina or death from heart disease, and that for every 39mg/dL reduction in LDL, the risk reduced by 24 percent.
Professor Ray added, "This study not only confirms that LDL can trigger heart problems, but also suggests reducing it in adults to very low levels - to those of a new-born baby - is both safe and beneficial."
He explained the team now need to gather longer-term data, to see if the beneficial effects continue. He added we need to wait until these trials have been fully analysed before we can fully assess the benefits of alirocumab.
- Kausik K. Ray et al., Reductions in Atherogenic Lipids and Major Cardiovascular Events, Circulation (2016),