Can Sleep Apnea Cause Alzheimer’s?

High quality sleep has long been linked to better brain health but a recent study has now linked sleep apnea (a known sleep sapper) to an increased risk of developing Alzheimer’s disease. The link between obstructive sleep apnea (not breathing), hypopnea (under-breathing) and dementia had been identified before, say experts, with age being the most common explanation, since sleep breathing problems tend to strike older adults.

In their recent study, researchers found that biomarkers for a compound called amyloid beta, the plaque-building peptides associated with Alzheimer’s disease, increased over time in elderly adults suffering from obstructive sleep apnea. Not surprisingly, individuals with more severe apnea were found to have a greater accumulation of these compounds over time.

Scientists say this study is the latest in series of similar findings. “Several other recent studies have suggested that sleep disturbances might contribute to amyloid deposits and accelerate cognitive decline in those at risk for Alzheimer’s,” said Ricardo S. Osorio, MD, senior study author and assistant professor of psychiatry at New York University School of Medicine.

This recent study, however, included 208 participants, age 55 to 90. All had normal cognition. Researchers performed lumbar punctures to obtain participants’ biomarker levels, and then used positron emission tomography, or PET, to measure biomarker deposits in their brains.

What do our experts have to say? “While this study does support a relationship between sleep apnea and dementia, we still don’t know the specifics yet,” explains Dr. Cynthia Bodkin, neurologist at Indiana University Health. “For instance, we know people with sleep apnea can also have hypertension, obesity and diabetes. We know that hypertension and diabetes can increase a person’s risk for developing dementia, as well. So, people who have sleep apnea sometimes have other health conditions that can increase their risk of developing dementia.”

That said, experts agree that the lack of brain oxygenation that occurs during sleep apnea can be detrimental to one’s health, particularly one’s brain health.

How? “When a person’s sleep is obstructed, they release chemicals called catechcholamines,” explains Dr. Bodkin. “These are the compounds which regulate one’s blood pressure and heart rate. Normally, when you sleep your blood pressure is low, but when you have sleep apnea this doesn’t happen and it creates more stress in your body. Surges in catecholamines can increase a person’s risk of stroke—and we know that strokes can create a climate in the brain that can increase a person’s risk of dementia.”

The bottom line: It’s difficult to know which clinical factors are currently at play with this study since obstructive sleep apnea and Alzheimer’s share risk factors and commonly coexist, explains Dr. Bodkin. “What we do know: Sleep apnea is treatable. So, if you have an issue, be proactive and see your doctor.”

— By Sarah Burns