In brief

• Research suggests elevated levels of “good” cholesterol lead to nearly 30% higher risk of dementia, over 40% for aged 75+.
• This connection remains even after accounting for various factors like age, physical activity, etc, though it does not establish causation.
• Findings challenge the traditional belief that high LDL cholesterol is always harmful.

A surprising study

In a surprising twist, a recent study led by Monash University has revealed that high levels of High-Density lipoprotein cholesterol (HDL-C), often considered “good” cholesterol for heart health, may be associated with an increased risk of dementia in older adults. 

The research, analyzing data from over 18,600 adults aged 65 and above in Australia and the US, found that individuals with high HDL-C levels had a nearly 30% higher risk of dementia on average. The risk steps up to more than 40% for those above 75 years of age. 

The association remains significant even after accounting for variables such as age, gender, educational background, alcohol consumption, and daily exercise. Note that this does not establish causation, merely indicating the presence of a correlation.

Rethinking what we know about cholesterol 

It’s the latest in a string of studies overturning what the medical profession thought it knew about cholesterol. A massive study published in the British Medical Journal in 2016 revealed that the pioneering studies linking cholesterol and saturated fats to heart disease were based on falsified data. (Link: https://www.bmj.com/content/353/bmj.i1246 )

Doctors have assumed that HDL cholesterol is “good”, while the other form, LDL, is “bad. Another big 2016 study blew a hole in the LDL theory big enough to drive a Big Mac through. The research team wanted to know what impact high cholesterol levels were having on a sample of 68,000 people over 60 who, by definition, were more likely to have a close encounter with the Grim Reaper because of their age. If high cholesterol killed, they reasoned, that’s where the bodies would be buried.

“If Goldstein and Brown’s recent statement that LDL-C is ‘the essential causative agent’ of cardiovascular disease CVD is correct, then we should find that LDL-C is a strong risk factor for mortality in elderly people.” (LINK: https://bmjopen.bmj.com/content/6/6/e010401.abstract )

Yet when they started digging, headstone after headstone was inscribed, “Here lies a person with low cholesterol”:

“The 4-year mortality among those with the highest LDL-C in the included cohorts was up to 36% lower than among those with the lowest LDL-C. Furthermore, in the largest study that included about two-thirds of the total number of participants in our study, the risk was lower among those with the highest LDL-C than among those on statin treatment.”

Which is safer? 

That last finding is a shocker: you are more likely to live if your bad cholesterol is high, than if you are on cholesterol-lowering medication.

“High LDL-C is inversely associated with mortality in most people over 60 years,” they wrote, meaning the lower the LDL level the higher the mortality rates. “This finding is inconsistent with the cholesterol hypothesis (ie, that cholesterol, particularly LDL-C, is inherently atherogenic). Since elderly people with high LDL-C live as long or longer than those with low LDL-C, our analysis provides reason to question the validity of the cholesterol hypothesis.”

The dementia link to “good” HDL cholesterol will further muddy the waters.