Frequent Naps Linked to 48% Higher Dementia Risk in Seniors

Jeff's Daily Pick. Older adults who nap most days had a 48% higher risk of dementia over 10 years. The naps you don't plan carried the clearest signal.

In the United States, researchers at the Johns Hopkins Bloomberg School of Public Health followed 995 Medicare beneficiaries aged 65 and older who were free of dementia in 2013, for up to 10 years. The results, published in The Journals of Gerontology: Series A, link how often, how intentionally and how long older people nap to their risk of developing dementia.

The numbers

The data came from the National Health and Aging Trends Study, a nationally representative survey. Compared with people who rarely or never napped, those who napped most days or every day had 1.48 times the hazard of possible or probable dementia (95% CI 1.14 to 1.94). Unintentional napping, meaning dozing off without planning to, carried a hazard ratio of 1.39 (95% CI 1.06 to 1.81). Infrequent and intentional naps showed no association. Naps of 30 minutes or less were linked to a 40% higher risk, while the link for longer naps weakened once nighttime sleep was considered.

The models adjusted for demographics, health conditions and nighttime sleep: duration, daytime sleepiness and a measure of obstructive sleep apnea risk. During follow up, 417 participants, about 42%, were classified as having possible or probable dementia.

Cause or clue

Senior author Adam Spira said more frequent napping could be a marker of brain changes rather than a cause of them. That reading fits earlier work showing that naps lengthen and multiply as Alzheimer disease progresses. The authors themselves write that napping "may be a modifiable risk factor for dementia if supported by further evidence" and call for studies with detailed napping data and longer follow up.

The practical value is as a signal. A parent who starts falling asleep in the afternoon without meaning to is showing a change worth mentioning to a doctor, along with snoring and poor night sleep. Our piece on deep sleep and tau covers the other side of the sleep and dementia question.