Science Update

Inadequate Sleep in Middle Age Associated with Increased Risk of Dementia

Dementia is the progressive deterioration of cognitive function and behavioral abilities due to neuronal cell death. Individuals with dementia often lose their memory, language skills, the ability to focus, visual perception, reasoning, and problem solving. Although dementia is more commonly diagnosed, with nearly 10 million new cases of dementia worldwide each year, it is not a normal part of aging. Research has shown that there may be various potential causes of dementia, including insulin resistance, diabetes, and hypertension. More recently, studies show that changes in sleep patterns and dysregulation of the sleep–wake cycle due to pathophysiological processes affecting the hypothalamus and brainstem are common in patients who have Alzheimer’s disease, but it remains unclear whether sleep duration prior to old age is correlated with an increased risk of cognitive decline and dementia.

According to a new longitudinal study published on April 20, 2021 in the journal of Nature Communications, sleeping 6 hours or less per night at 50 and 60 years of age was associated with a higher risk of late-onset dementia compared with those who sleep at least 7 hours per night. Researchers analyzed data from 7,959 individuals who participated in the Whitehall II study starting in 1985 and followed their health for 25 years extracting data on their sleep duration at ages 50, 60, and 70 years. Sleep duration was self-reported among the participants; however, 3,900 study participants also wore a watch device overnight. Persistent short sleep duration was associated with a 30% increased dementia risk among all age groups; however, after adjusting for cardiometabolic or mental health issues, which are known risk factors of dementia, sleep duration at age 70 was not associated with dementia. The lowest dementia incidence was observed among participants who slept at least 7 hours per night, regardless of their age when the sleep duration was measured. This study showed no correlation between long sleep duration and dementia incidence.

Aside from recommending middle-aged individuals (approximate age range, 45 to 65 years) to adopt an anti-inflammatory, whole food diet that is low in refined carbohydrates with minimal added sugars, along with a moderate intensity exercise regimen, patients may find taking sleep-supportive nutrients and botanicals with relaxing properties to be helpful for improving overall sleep duration. Melatonin, inositol, L-theanine, 5-hydroxytryptophan (5-HTP), gamma-aminobutyric acid (GABA), Montmorency tart cherry powder, and other calming herbs, such as lavender, California poppy, chamomile, passion flower, and valerian root. Magnesium supplementation has been shown to support overall relaxation, sleep time, and sleep efficiency, whereas magnesium deficiency has been shown to negatively affect sleep quality.

Encourage patients to avoid excessive alcohol or caffeine intake and to avoid eating too close to bedtime to help reduce sleep latency. Excessive stress and insufficient daytime exposure to natural sunlight can also reduce the body’s natural production of melatonin; therefore, getting outside during the day and managing stress may support the body’s natural sleep–wake cycle and support healthy aging and brain function.

By Caitlin Higgins, MS, CNS, LDN