The idea that LDL cholesterol levels could affect mental health is not new, but a European study has found that the amount of fluctuation between cholesterol measurements—rather than average cholesterol readings—may have mental health implications for the elderly.
The researchers examined 4, 428 participants across Scotland, Ireland, and the Netherlands who either had preexisting vascular disease or were at high risk of developing vascular disease due to the presence of things like cigarette smoking, diabetes, or hypertension in their history. The variability of LDL (the “bad” cholesterol) was assessed by taking measurements over the course of various doctor visits and assessing how much the observed LDL levels went up or down. A set of four cognitive function tests were used to assess selective attention, information processing speed, and immediate and delayed verbal memory recall.
It was found that the higher variability in LDL levels was correlated to poorer performance on the cognitive tests, regardless of what the actual average cholesterol level was. For instance, participants who had the highest LDL variability took an average of 2.7 seconds longer to complete. The effect is definitely small, but it was consistent enough across the study’s population to suggest a connection of some form. Lower levels of brain blood flow and greater intensity loads on the brain’s white matter were also observed among the higher variability cases. Such load types have been associated with endothelial dysfunctions in past research.
Interestingly, the researchers didn’t notice any impact from the use of cholesterol-lowering statins. This suggests the possibility that the connection between LDL cholesterol and mental health effects may be indirect in nature—that the cholesterol connection is only a manifestation of another, unidentified variable. It could also mean, however, that statins aren’t strong enough to counteract the effect, among other possible explanations. The idea of variability in LDL cholesterol having an impact on mental health is still relatively new and research is still in its early stages. Fortunately, science is nothing if not persistent and more research on a broader selection of subjects will allow for more understanding of the phenomenon.
“Fluctuations in “bad” cholesterol may be linked to worse brain health,” American Heart Association web site, July 18, 2016; http://newsroom.heart.org/news/fluctuations-in-bad-cholesterol-may-be-linked-to-worse-brain-health?preview=97b3, last accessed July 19, 2016.
Roelof, A., et. al., “Higher Visit-to-Visit Low-Density Lipoprotein Cholesterol Variability Is Associated With Lower Cognitive Performance, Lower Cerebral Blood Flow, and Greater White Matter Hyperintensity Load in Older Subjects,” Circulation, 2016; http://dx.doi.org/10.1161/CIRCULATIONAHA.115.020627.