A group of researchers at Johns Hopkins University, the Mayo Clinic, and Columbia University may have found a biomarker (or a measurable, identifiable indicator) that predicts the onset of Alzheimer’s Disease (AD). Further research will be needed, but in a pilot study of women between the ages of 70 and 79, high levels of a particular kind of fat molecule in the blood predicted a significantly higher risk of developing AD.
The researchers behind the current study previously identified an association between this type of molecule, a related group of fat molecules known as ceramides, and cognitive decline. It was unclear from this previous research whether high ceramide levels might actually lead to AD or other dementia. To determine if further research in this area would be promising, the researchers conducted a pilot study with 99 participants, a subset of the longitudinal, population-based Women’s Health and Aging Study II.
As part of their participation in the Women’s Health and Aging Study, the participants in the pilot study had their blood drawn at baseline (or the beginning of their participation in the study), and received up to six subsequent physical and cognitive examinations over nine years. The participants in the ceramide level pilot study were randomly chosen from those participants in the larger study who did not have dementia at baseline and for whom the researchers were able to access a sufficient baseline blood sample.
The researchers were then able to analyze whether ceramide level was predictive of AD within this subset of participants. The researchers divided the sample into the lowest, middle, and highest thirds of ceramide levels within the samples, in part because scientists have yet to establish a normal range of ceramide levels.
The middle and highest thirds of the sample were about ten times more likely to develop AD than those in the lowest third, even when factoring in the participants’ age, body mass, and blood glucose level, which is also associated with AD. Three particular ceramides were particularly predictive of higher risk. The authors note the possibility that it may be the case that low levels of ceramides may be a distinctive characteristic that reduces the risk of AD, since both the middle and highest third had elevated risk.
These findings are very promising for future research, which some day might be able to identify individuals at risk for AD. There are important limitations to the study, however, such as the relatively small sample size which limits the generalizability of the study. Further, it is unclear whether these findings would apply to men, to less physically healthy older adults, or to older or younger individuals. Regardless, these findings show that the relationships between ceramides and AD should be studied in larger samples
Mielke MM, Bandaru VVR, et al. Serum ceramides increase the risk of Alzheimer disease: The Women’s Health and Aging Study II. Neurology; (2012). 79: 633-640.