Elevated cholesterol levels have been linked to increased risk of Alzheimer’s later in life.
By contrast Early-onset Alzheimer’s is a relatively rare form of the condition. The disease is considered “early-onset” when it appears before age 65. About 10% of all Alzheimer’s cases are early-onset. Past research has shown that the condition is largely genetics-based, meaning it is likely to be inherited if a parent has it.
To test whether early-onset Alzheimer’s disease is linked to cholesterol and identify the genetic variants that might underlie this possible association, the researchers in this study sequenced specific genomic regions of 2,125 people, 654 of whom had early-onset Alzheimer’s and 1,471 of whom were controls. They also tested blood samples of 267 participants to measure the amount of LDL cholesterol.
They found that APOE E4 explained about 10% of early-onset Alzheimer’s, which is similar to estimates in late-onset Alzheimer’s disease. The researchers also tested for APP, PSEN1, and PSEN2 (known to be related to early-onset Alzheimer’s disease). About 3% of early-onset Alzheimer’s cases had at least one of these known early-onset Alzheimer’s risk factors.
After testing blood samples, the researchers found that participants with elevated LDL levels were more likely to have early-onset Alzheimer’s disease, compared with patients with lower cholesterol levels. This was true even after the researchers controlled for cases with the APOE mutation, meaning cholesterol could be an independent risk factor for the disease, regardless of whether the problematic APOE gene variant is present.
“Association of Early-Onset Alzheimer Disease With Elevated Low-Density Lipoprotein Cholesterol Levels and Rare Genetic Coding Variants of APOB | Cardiology | JAMA Neurology | JAMA Network.” Accessed May 29, 2019. https://jamanetwork.com/journals/jamaneurology/article-abstract/2734865.