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.
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.
"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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