In a new study researchers from Mount Sinai noted that among people over the age of 85, raised levels of blood cholesterol can actually be good for health – reducing the risk of dementia and cognitive decline. The study was released in the online issue of the Alzheimer's & Dementia: The Journal of the Alzheimer's Association yesterday (5th of March 2018).
Cholesterol plaque in artery. Image Credit: hywards / Shutterstock
Cholesterol is a normal part of the body that is necessary for the growth and development and several essential functions of the body. However excess of cholesterol in blood has been tied to raising the risk of coronary artery disease or cardiovascular disease, heart attacks and stroke. Cholesterol lowering drugs thus are prescribed to reduce the risk of these diseases.
Studies have shown that cholesterol is linked with mental acuity and functions including level of concentration and attention, speed of learning, cognitive abilities, processing speed, verbal fluency and memory. With age these abilities tend to deteriorate especially in those suffering from dementia including Alzheimer’s disease. Studies have also shown that alipoprotein E is a protein that carries cholesterol in the brain and is linked with development of late-onset Alzheimer’s.
The authors of this new study looked at the association of cholesterol levels and cognitive functions at different age groups. The team looked at data from the Framingham Heart Study that is an ongoing large study on the population of Framingham, Massachusetts. The study had started in 1948 with a total of 5,209 adults and now the third generation of those participants are also part of this study. They checked upon the total cholesterol values during the middle years of the participants and in the late years. Middle years are those around 40 and later years are those around 75 years of age, they write. They also looked at cognitive tests performed at different ages of the participants. Five different values were tested – total cholesterol at average age 40 years, total cholesterol at average age 77 years, mean total cholesterol since mid life or middle years, linear change since midlife or increase or decrease of the cholesterol and quadratic change since midlife or the pattern of acceleration or deceleration of the cholesterol levels.
Results revealed that increased cholesterol levels since the 40’s led to an increased cognitive decline as the participant aged. However with age this positive correlation was stopped and ultimately reversed. In patients between ages 85 and 94 years for example, having higher cholesterol during middle years led to a lower risk of cognitive decline. This goes against the traditional study findings from other researchers.
Authors warn that this study does not advocate raising one’s cholesterol during their 40’s to reduce the risk of cognitive decline. This is because, there is a positive risk of getting dementia among the aged if they have high cholesterol levels during their 40’s. Further high cholesterol levels do lead to an increased risk of cardiovascular disease.
Study's first author, Jeremy Silverman, PhD, Professor of Psychiatry, Icahn School of Medicine at Mount Sinai said that this study was important “for researching genetic and other factors associated with successful cognitive aging.” He also warned that this study does not imply people should increase their cholesterol levels. He explained that there could be a genetic basis to the purported protective effects of high cholesterol on cognitive abilities among the elderly.