It hints that falling total cholesterol levels after middle age may point to an ongoing disease processes in the brain, and could be a marker for risk of late-life cognitive impairment.
Dr. Miia Kivipelto, from the Aging Research Center at the Karolinska Institute in Stockholm, Sweden, and colleagues investigated changes in total cholesterol levels in relation to cognitive functioning in late-life.
The study involved some 2000 people who had their cholesterol level measured in midlife, and were re-examined an average of 21 years later.
The team focused on 70 people who developed mild cognitive impairment during follow-up, 48 who developed Alzheimer\’s disease and a "control" group of 1,203 people who remained mentally intact.
"Mid-life total cholesterol represented a risk factor for more severe cognitive impairment later in life," the researchers found, with significant differences between the controls, those with mild cognitive impairment, and those with dementia.
On the other hand, a moderate drop in total cholesterol from mid-life to late-life "was significantly associated with the risk of a more impaired late-life cognitive status," the investigators report in the medical journal Neurology.
These findings remained unchanged after adjusting for factors that might influence brain function, including age, sex, education and even the presence APOE-4 gene, which is known to predispose people to develop Alzheimer\’s disease.
Kivipelto and colleagues believe that declining cholesterol after middle age may "reflect ongoing pathological processes in the brain." Nonetheless, they say the relationship between cholesterol and dementia is "controversial," and meanwhile, they point out, high cholesterol "carries risk even in old age, and results from clinical trials in vascular diseases support the benefit of lipid-lowering treatment in elderly patients."
SOURCE: Neurology, March 2007.