Less than five hours of sleep a night 'can double dementia risk' 

Researchers found a doubled risk of dementia for adults over 65 who had five hours or less of sleep per night, compared to those who had seven to eight hours. https://www.dailymail.co.uk/sciencetech/article-9253509/Less-five-hours-sleep-night-double-dementia-risk.html?ns_mchannel=rss&ns_campaign=1490&ito=1490