A new study adds to growing evidence of a link between sleep problems and Alzheimer’s. The interesting thing is that this association – between sleep apnea and Alzheimer’s biomarkers — wasn’t revealed until the data was separated out according to BMI.
Those with sleep apnea and a BMI under 25 showed several Alzheimer’s biomarkers (increased levels of tau in the cerebrospinal fluid, greater atrophy of the hippocampus, glucose hypometabolism in regions vulnerable to Alzheimer’s). This (with the exception of glucose hypometabolism in the mediotemporal lobe only) was not found in those with sleep apnea and a higher BMI.
The study involved 68 healthy older adults (average age 71), of whom 18 had normal breathing, 33 mild sleep apnea, and 17 moderate-severe apnea. Those in the latter group tended to have higher BMIs.
Some 10-20% of middle-aged adults in the U.S. have sleep apnea, and this jumps dramatically in those over 65 (30-60%), where the link to obesity is much smaller. The researchers suggest that early preclinical Alzheimer’s damage might be a reason, and plan follow-up research to assess what impact CPAP therapy for sleep apnea has on the Alzheimer’s biomarkers.
Those interested in the relationship between poor sleep and later development of Alzheimer’s might also like to read a Guardian article on the subject.
Osorio, R.S. et al. 2013. Sleep-Disordered Breathing, Aging And Risk For Alzheimer's Disease In Cognitively Normal Subjects. Abstract 38456. Presented at the ATS 2013 International Conference.