Study: Too Little and Too Much Sleep Linked to Cognitive Decline

Tamara Bhandari wrote . . . . . . . . .

Like so many other good things in life, sleep is best in moderation. A multiyear study of older adults found that both short and long sleepers experienced greater cognitive decline than people who slept a moderate amount, even when the effects of early Alzheimer’s disease were taken into account. The study was led by researchers at Washington University School of Medicine in St. Louis.

Poor sleep and Alzheimer’s disease are both associated with cognitive decline, and separating out the effects of each has proven challenging. By tracking cognitive function in a large group of older adults over several years and analyzing it against levels of Alzheimer’s-related proteins and measures of brain activity during sleep, the researchers generated crucial data that help untangle the complicated relationship among sleep, Alzheimer’s and cognitive function. The findings could aid efforts to help keep people’s minds sharp as they age.

The findings are published in the journal Brain.

“It’s been challenging to determine how sleep and different stages of Alzheimer’s disease are related, but that’s what you need to know to start designing interventions,” said first author Brendan Lucey, MD, an associate professor of neurology and director of the Washington University Sleep Medicine Center. “Our study suggests that there is a middle range, or ‘sweet spot,’ for total sleep time where cognitive performance was stable over time. Short and long sleep times were associated with worse cognitive performance, perhaps due to insufficient sleep or poor sleep quality. An unanswered question is if we can intervene to improve sleep, such as increasing sleep time for short sleepers by an hour or so, would that have a positive effect on their cognitive performance so they no longer decline? We need more longitudinal data to answer this question.”

Alzheimer’s is the main cause of cognitive decline in older adults, contributing to about 70% of dementia cases. Poor sleep is a common symptom of the disease and a driving force that can accelerate the disease’s progression. Studies have shown that self-reported short and long sleepers are both more likely to perform poorly on cognitive tests, but such sleep studies typically do not include assessments of Alzheimer’s disease.

To tease apart the separate effects of sleep and Alzheimer’s disease on cognition, Lucey and colleagues turned to volunteers who participate in Alzheimer’s studies through the university’s Charles F. and Joanne Knight Alzheimer Disease Research Center. Such volunteers undergo annual clinical and cognitive assessments, and provide a blood sample to be tested for the high-risk Alzheimer’s genetic variant APOE4. For this study, the participants also provided samples of cerebrospinal fluid to measure levels of Alzheimer’s proteins, and each slept with a tiny electroencephalogram (EEG) monitor strapped to their foreheads for four to six nights to measure brain activity during sleep.

In total, the researchers obtained sleep and Alzheimer’s data on 100 participants whose cognitive function had been monitored for an average of 4 1/2 years. Most (88) had no cognitive impairments, 11 were very mildly impaired, and one had mild cognitive impairment. The average age was 75 at the time of the sleep study.

The researchers found a U-shaped relationship between sleep and cognitive decline. Overall, cognitive scores declined for the groups that slept less than 4.5 or more than 6.5 hours per night — as measured by EEG — while scores stayed stable for those in the middle of the range. EEG tends to yield estimates of sleep time that are about an hour shorter than self-reported sleep time, so the findings correspond to 5.5 to 7.5 hours of self-reported sleep, Lucey said.

The U-shaped relationship held true for measures of specific sleep phases, including rapid-eye movement (REM), or dreaming, sleep; and non-REM sleep. Moreover, the relationship held even after adjusting for factors that can affect both sleep and cognition, such as age, sex, levels of Alzheimer’s proteins, and the presence of APOE4.

“It was particularly interesting to see that not only those with short amounts of sleep but also those with long amounts of sleep had more cognitive decline,” said co-senior author David Holtzman, MD, a professor of neurology. “It suggests that sleep quality may be key, as opposed to simply total sleep.”

Each person’s sleep needs are unique, and people who wake up feeling rested on short or long sleep schedules should not feel compelled to change their habits, Lucey said. But those who are not sleeping well should be aware that sleep problems often can be treated.

“I ask many of my patients, ‘How’s your sleep?’” said co-senior author Beau M. Ances, MD, PhD, the Daniel J. Brennan, MD, Professor of Neurology. Ances treats patients with dementia and other neurodegenerative conditions at Barnes-Jewish Hospital. “Often patients report that they’re not sleeping well. Often once their sleep issues are treated, they may have improvements in cognition. Physicians who are seeing patients with cognitive complaints should ask them about their quality of sleep. This is potentially a modifiable factor.”

Source: Washington University School of Medicine

What’s for Lunch?

Shrimp Tempura Soba Lunch Set at Dining Cafe Chigusa in Kitakyushu, Japan

The price is 1,870 yen (tax included).

Heartburn Meds Might Be Good for Your Gums

While they’re helping to ease reflux, some heartburn drugs may also be reducing the severity of gum disease, new research suggests.

For the study, researchers assessed probing depth in the gums (the gap between teeth and gums) in more than 1,000 patients with gum disease who were or weren’t using drugs called proton pump inhibitors (PPIs), a class of drugs widely prescribed to treat heartburn, acid reflux and ulcers.

Probing depth is an indicator of gum disease (periodontitis) severity. When gums are healthy, they fit snugly against the teeth and there is a smaller probing depth.

The lower severity of gum disease associated with PPIs may be due to how the drugs alter bone metabolism and the gut microbiome, according to lead investigator Dr. Lisa Yerke. She is a clinical assistant professor at the University at Buffalo School of Dental Medicine, in New York.

PPIs include drugs like Prilosec (omeprazole) and Nexium (esomeprazole).

Probing depths of 6 millimeters (mm) or more were found in 14% of teeth in patients who used PPIs, compared with 24% of teeth from patients who did not use PPIs, the findings showed.

Probing depths of 5 mm or more were found in 27% of teeth in patients using PPIs, compared with 40% of teeth from those not using PPIs, the study authors reported.

The results were recently published online in the journal Clinical and Experimental Dental Research.

“PPIs could potentially be used in combination with other periodontal treatments; however, additional studies are first needed to understand the underlying mechanisms behind the role PPIs play in reducing the severity of periodontitis,” Yerke said in a university news release.

The study cannot prove a cause-and-effect relationship. Further research is being planned to learn whether this association between PPIs and gum disease can be found in other groups of patients, and to determine how much of this relationship is directly attributable to PPIs, Yerke said.

Source: HealthDay

Sea Bass with Ginger Beer and Bok Choy


1 bunch bok choy (about 1 pound)
Kosher salt
4 Chilean sea bass fillets (6 to 8 ounces each)
freshly ground black pepper
1 tablespoon dark sesame oil
4 tablespoons (1/2 stick) unsalted butter
one 12-ounce bottle ginger beer
1-inch knob fresh ginger, peeled and grated
juice of 1 lime
2 to 3 tablespoons chopped fresh cilantro, or 2 lime leaves, sliced (optional)


  1. Trim the bok choy and cut out any thick stems. Rinse under cool, running water and shake most of the water from the leaves.
  2. Pour water into a large, deep skillet to a depth of 2 inches or so and season lightly with salt. Put a steamer basket over the water and bring to a boil over high heat. Put the bok choy leaves (they don’t have to be dry) in the skillet, salt lightly, cover the pan, and reduce the heat to medium. Steam the bok choy until the leaves wilt, 7 to 9 minutes. Remove the lid from the skillet and continue cooking for about 1 minute to evaporate any excess water clinging to the leaves (there will be some water in the pan, but no worries).
  3. Season the sea bass fillets on both sides with salt and pepper.
  4. In a large sauté pan, heat the sesame oil with 1 tablespoon of the butter over medium-high heat. When hot, add the fillets and cook until golden brown and cooked through, 4 to 5 minutes per side. Remove the fillets from the heat, set aside on a plate, and cover with aluminum foil to keep warm.
  5. Pour the ginger beer into the sauté pan (after you’ve taken a few nips yourself) and stir to mix with the pan juices. Bring to a boil over high heat, reduce the heat a little, and simmer until the beer evaporates, leaving a thickish, slightly oozy glaze in the pan, 8 to 10 minutes. As the pan sauce simmers, stir it with a wooden spoon to scrape any browned bits from the bottom of the pan.
  6. Add the grated ginger and lime juice to the pan and swirl to mix. Add the remaining 3 tablespoons butter and stir until the pan sauce is smooth and thick.
  7. Serve the fillets on top of the wilted bok choy. Spoon a little sauce over the fish and garnish with the cilantro, if desired

Makes 4 servings.

Source: So Good

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