Alzheimer’s Plaques May Be Bigger Risks Than Gene, Study Says

People with plaques in the brain associated with Alzheimer’s disease may have a greater risk for cognitive impairment than those who have a gene tied to the dementia-causing illness, Australian researchers found.

In a study of 141 healthy subjects, those with clumps of amyloid beta plaques in their brains at the start of the study had as much as a 20 percent greater decline in memory and thinking over an 18-month period than those with fewer plaques. The research also showed that patients with the gene linked to Alzheimer’s, called ApoE4, had a greater mental decline, though having the gene didn’t alter the decline related to the plaques.

The findings, published today in the journal Neurology, suggest that brain plaques may be a more important factor in determining Alzheimer’s risk than the gene, said Yen Ying Lim at Florey Institute of Neuroscience and Mental Health in Melbourne, who led the study. More than a century after it was first identified, scientists have yet to find a cause or a cure for the memory-robbing disease that afflicts 36 million people worldwide.

“If you have high amyloid, whether you have the gene or not seems to not really affect that,” Lim said in an interview. “This could provide us with a platform to begin to investigate whether drugs designed to stop amyloid accumulation in the brain can actually prevent people from getting to the more severe stages of the disease.”

An estimated 36 million people suffer from Alzheimer’s disease and the figure is projected to increase to 115 million people by 2050 by a nonprofit group American Health Assistance Foundation.

Experimental Drugs

Drug companies including Eli Lilly & Co. (LLY), GlaxoSmithKline Plc (GSK), Elan Corp. and Prana Biotechnology Ltd. (PBT) are racing to develop drugs that target beta amyloid plaques.

On Oct. 8, Lilly reported that its Alzheimer’s treatment, solanezumab, slowed memory loss and cognitive decline in early- stage patients by about 30 percent. The findings offered the first evidence that a medication may hamper the course of the disease, researchers said.

The study reported today involved healthy adults with an average age of 76 years old who were free of problems in memory and thinking. They were tracked for 18 months using computer- based cognitive tests based on playing card games and remembering word lists. They also underwent PET brain scanning and were tested for the ApoE4 gene, which is found in about half of Alzheimer’s patients.

To contact the reporter on this story: Kanoko Matsuyama in Tokyo at kmatsuyama2@bloomberg.net.

To contact the editor responsible for this story: Jason Gale in Melbourne at j.gale@bloomberg.net

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