Trend: Growing research on the relationship between sleep and Alzheimer’s Disease

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The brain may clean out Alzheimer’s plaques dur­ing sleep (Sci­ence­News):

“Bendlin’s stud­ies are part of a mod­est but grow­ing body of research sug­gest­ing that a sleep-deprived brain might be more vul­ner­a­ble to Alzheimer’s dis­ease. In ani­mal stud­ies, lev­els of plaque-form­ing A‑beta plum­met dur­ing sleep. Oth­er research sug­gests that a snooz­ing brain runs the “clean cycle” to remove the day’s meta­bol­ic debris — notably A‑beta — an action that might pro­tect against the dis­ease … But while the new research is com­pelling, plen­ty of gaps remain. There’s not enough evi­dence yet to know the degree to which sleep might make a dif­fer­ence in the dis­ease, and study results are not consistent.

A 2017 analy­sis com­bined results of 27 stud­ies that looked at the rela­tion­ship between sleep and cog­ni­tive prob­lems, includ­ing Alzheimer’s. Over­all, poor sleep­ers appeared to have about a 68 per­cent high­er risk of these dis­or­ders than those who were rest­ed, researchers report­ed last year in Sleep. That said, most stud­ies have a chick­en-and-egg prob­lem. Alzheimer’s is known to cause dif­fi­cul­ty sleep­ing. If Alzheimer’s both affects sleep and is affect­ed by it, which comes first? …

The cen­tral ques­tion — the one that doc­tors real­ly want to answer — is whether bet­ter sleep could treat or even pre­vent Alzheimer’s. To try to fig­ure this out, Bendlin and her Wis­con­sin col­leagues are now study­ing peo­ple with sleep apnea. Peo­ple with that con­di­tion stop breath­ing dur­ing the night, which wakes them up and makes for a lousy night’s sleep. A machine called a CPAP, short for con­tin­u­ous pos­i­tive air­way pres­sure, treats the condition.

“Once peo­ple start treat­ment, what might we see in the brain? Is there a ben­e­fi­cial effect of CPAP on mark­ers of Alzheimer’s?” Bendlin won­ders. “I think that’s a big ques­tion because the impli­ca­tions are so large.”

The Study:

Sleep, Cog­ni­tive impair­ment, and Alzheimer’s dis­ease: A Sys­tem­at­ic Review and Meta-Analy­sis (Sleep). From the Abstract:

  • Objec­tives: Mount­ing evi­dence impli­cates dis­turbed sleep or lack of sleep as one of the risk fac­tors for Alzheimer’s dis­ease (AD), but the extent of the risk is uncer­tain. We con­duct­ed a broad sys­tem­at­ic review and meta-analy­sis to quan­ti­fy the effect of sleep problems/disorders on cog­ni­tive impair­ment and AD.
  • Con­clu­sion: This meta-analy­sis con­firmed the asso­ci­a­tion between sleep and cog­ni­tive impair­ment or AD and, for the first time, con­sol­i­dat­ed the evi­dence to pro­vide an “aver­age” mag­ni­tude of effect. As sleep prob­lems are of a grow­ing con­cern in the pop­u­la­tion, these find­ings are of inter­est for poten­tial pre­ven­tion of AD.

The Study in Context: