Frequent use of sleep medications may increase the risk of future cognitive impairment, new research suggests.
Investigators Yue Leng, PhD, and Kristine Yaffe, MD, University of California, San Francisco, found that older adults who reported taking sleep medications often were more than 40% more likely to develop dementia over 15 years than their peers who rarely, or never, took sleeping pills.
"While we don't know the exact mechanism underlying this association, we hope this research will raise caution among clinicians when prescribing sleep medications to those at high risk for dementia," said Leng. She reported the results during a press briefing here at the Alzheimer's Association International Conference (AAIC) 2019.
"Sleeping pills are one of the most frequently prescribed medications in the US among older adults. It's estimated that 1 in every 5 older adults takes sleep medications regularly," said Leng.
"Surprisingly, the effects of sleep medication use in older adults is poorly understood. Most previous research has focused on short-term adverse events related to use of sleep medications, such as increased risk of falls or increased risk of short-term memory loss. The long-term effects of sleep medication use on cognition is unclear," Leng noted.
To evaluate ties between sleep medication use and dementia risk, Leng and colleagues examined 3068 black and white community-dwelling older adults without dementia aged 70 to 79 years from the Health, Aging, and Body Composition (Health ABC) study. Participants reported sleep medication use in 1997–1998 and were followed until 2013.
- A total of 147 (4.8%) participants reported taking sleep medications "sometimes" (2 to 4 times per month), and 172 (5.6%) reported taking sleep medications "often" (5 to 15 times monthly) or “almost always" (16 to 30 times monthly).
- Whites were more likely than blacks to report taking sleep medications "often" or "almost always" (8% vs 3%). More frequent users were also more likely to be women and have a history of coronary heart disease and depression.
- Older adults who reported taking sleep medications "often" or "almost always" were 43% more likely to develop dementia than those who never or rarely used sleep medications (hazard ratio [HR], 1.43; 95% confidence interval [CI], 1.01 - 2.02).
- White participants reporting frequent use had a 79% higher dementia risk (HR, 1.79; 95% CI, 1.21 - 2.66). There was no association in blacks (HR = 0.84; 95% CI, 0.38 - 1.83). The association did not differ by sex.
The associations were independent of age, sex, education, socioeconomic status, smoking, alcohol use, body mass index, depressive symptoms, physical activity, comorbidities, APOE 4 genotype and sleep disturbances.
"The use of sleep medication may be a risk factor for later cognitive impairment," said briefing moderator David Knopman, MD, a clinical neurologist at the Mayo Clinic in Rochester, Minnesota, and member of the Alzheimer's Association Medical and Scientific Advisory Group.
"Over the lifespan, sleep is clearly a marker of brain health and health generally. Whether sleep is directly related to AD [through] excess accumulation of beta-amyloid and tau proteins, or whether it's a marker of more general nonspecific health, is something that is a very active area of research," said Knopman.
While the study shows an association between the use of sleep medications and subsequent cognitive impairment, it does not show causality, he cautioned.
"One cannot say from the study that sleep medication causes future cognitive impairment," said Knopman. Gaining a better understanding of the mechanisms for this association is a "key issue for future research.”
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