A number of studies have suggested that sleep-disordered breathing (SDB) may be a risk factor for developing Alzheimer’s disease. Now, a study from the U.S. has found that a preclinical stage of the condition could be recognized by testing SDB patients for specific biomarkers.
In the study, 68 cognitively normal participants aged 64 to 87 underwent comprehensive clinical examination, neuropsychological testing, two nights of home monitoring of SDB, and a number of procedures used for Alzheimer’s diagnosis. Eighteen (26.5 percent) had normal breathing, 33 (48.5 percent) mild SDB and 17 (25 percent) moderate–severe SDB.
Adjusting for weight, the researchers found that participants with SDB who had a body mass index lower than 25 possessed several biomarkers of Alzheimer’s disease risk. However, no such link was found in obese patients (BMI > 25).
“We know that about 10 to 20 percent of middle-aged adults in the U.S. have SDB and that the number jumps dramatically in those over 65,” said Dr. Ricardo Osorio, lead researcher and research assistant professor at New York University’s School of Medicine. “We don’t know why it becomes so prevalent but one factor may be that some of these patients are in the earliest stages of Alzheimer’s disease.” He further pointed out that the biochemical harbingers of the disease are present 15 to 20 years before any other symptom.
In order to determine the direction of the causality between SDB and preclinical Alzheimer’s disease, the researchers are planning a two-year trial with 200 cognitively normal subjects who would be given continuous positive airway pressure (CPAP) to treat their sleep apnea. After six months, they would be examined again for the presence of potential biomarkers of Alzheimer’s disease.
“If biomarkers change, it may indicate that SDB is causing Alzheimer’s disease. If they don’t change, the probable conclusion is that patients are going to develop Alzheimer’s with or without CPAP and that Alzheimer’s may either be causing the apneas or coexist with SDB as part of aging,” Osorio said.
Original Source: The Dental Tribune.com