Credit: (John J. LaRosa | For NJ Advance Media )

When asked to grade herself, Peggy Koon gave herself only a C+.

The issue was the quality of her sleep, and on that front, she had to admit she was barely passing.

The 84-year-old East Orange retiree knew the culprit: Chica, the adorable pit bull she calls her “grand-dog.” Chica would sleep with her, then insist on being let outside at 2 a.m. to do her business.

Koon assessed her sleep as one of the 114 participants in a recent study that made national news by revealing a good night’s sleep appears to protect some African Americans from Alzheimer’s disease.

“Oh, that’s wonderful! That’s really, really wonderful!” she said when told of the findings.

When it comes to Alzheimer’s disease, Black people face a double whammy: They are more than twice as likely as white people to develop the disease, yet are underrepresented in medical research.

Dr. Mark Gluck is working hard to address that second problem. The laboratory he runs at Rutgers University’s Newark campus, called the Aging & Brain Health Alliance, is exploring ways that lifestyle choices can protect against Alzheimer’s in this population.

The most common risk factor

Researchers have long known of the link between lousy sleep and Alzheimer’s. And in recent years, they’ve also pinpointed a risky variant of a gene, called the ABCA7, the most common risk factor for Alzheimer’s among people of African descent.

Gluck and his colleagues devised a way to see if good sleep could lower the risk posed by that variant.

They asked 114 cognitively healthy volunteers from Newark and surrounding towns to have their DNA analyzed for the gene variant and then to take a battery of simple cognition tests. Finally, the participants were asked to rate their sleep. (It was at this point Koon realized the hard truth about Chica.)

They crunched the numbers, and voila! It turns out that people who have the risky gene variant but report getting enough quality sleep seem to be protected from developing the earliest signs of Alzheimer’s.

That makes perfect sense to Gluck. We think of sleep as a time when nothing happens except dreams of flying carpets or nightmares about taking a test for which we’ve never studied. Yet the brain uses this downtime to undertake basic maintenance tasks.

Gluck likens it to the way city garbage collectors pick up the trash in the predawn hours.

“Every cell is like a home — it generates garbage,” he said. “The problem becomes if that garbage doesn’t get picked up.” Truncated sleep can allow toxins to build up in the brain.

‘While it is common to think of genetics as marking our destiny, these results suggest that with the right behavioral modifications, we might be able to overcome some of our genetic predispositions to this terrible disease.’ — Dr. Mark Gluck, Aging & Brain Alliance, Rutgers University

On average, African Americans get an hour less of sleep each night. (And to be clear, that’s not because they need less sleep than other races.) The possible causes of this racial “sleep gap” range from the greater likelihood of working night shifts (or sharing living quarters with someone who works those hours), to the greater likelihood of suffering from sleep apnea.

The study findings about the importance of sleep help people realize that modest changes in daily life might help forestall the onset of Alzheimer’s, Gluck said.

“While it is common to think of genetics as marking our destiny, these results suggest that with the right behavioral modifications, we might be able to overcome some of our genetic predispositions to this terrible disease.”

Family history, genetic makeup

He envisions a time when doctors will look at a patient’s family history and genetic makeup and issue a “prescription” for better sleep.

The very act of thinking about the quality of her sleep prompted Koon to make some changes. She now drinks some ginger and honey tea at night, and more importantly, has placed her beloved Chica on a tight schedule. The dog visits the backyard at 11:30 p.m., which lets both of them sleep through the night.

While she doesn’t think Alzheimer’s disease runs in her family, she’s taking no chances. That’s why she has volunteered for the Rutgers studies for five years now. “If anything is going on, I want to handle it before it gets out of control,” she said.

Good sleep has become another tool in her healthy lifestyle tool kit. She exercises four days a week and takes a “Senior Defense” course through the City of East Orange every Friday.

“I want to be healthy,” says this retiree, who worked until she was 80. “I want to stay healthy.”