A study of around 8,000 civil servants has found that getting at least five hours' sleep a night could significantly reduce over-50s' chances of developing multiple chronic health problems.
The analysis, led by UCL researchers was based on the ongoing Whitehall II study, which has gathered data on the health of 10,308 officials since 1985.
Data from 7,864 participants – those who didn't already have multi-morbidity aged 50 and who continued providing results throughout the study – informed the sleep findings.
Study participants – all of whom were British civil servants based in London offices when the research began, and a third of whom are women – were asked how many hours of sleep they got on an average weeknight. Some also wore a wrist-watch sleep tracker.
They were checked for chronic conditions including diabetes, cancer, heart disease and dementia.
Researchers found people who reported getting five hours of sleep or less at age 50 were 20% more likely to have been diagnosed with a chronic disease and 40% more likely to be diagnosed with two or more chronic diseases over 25 years, compared to people who slept for up to seven hours.
Sleeping for five hours or less at the age of 50, 60, and 70 was linked to a 30-40% increase in the risk of multi-morbidity compared with those who slept for up to seven hours. Researchers also found that sleeping five hours or less a night at age 50 was associated with a 25% increased risk of death over the 25-year timeline. They attributed this mainly to the increased incidence of chronic disease, which in turn increases the risk of death.
While the study found no strong association between long sleep (over nine hours) and risk of chronic disease or multi-morbidity, it did find some evidence that those who already had a chronic condition were more likely to develop further conditions if they regularly slept for over nine hours.
The study aimed to understand the link between sleep duration and the development of multiple chronic diseases and mortality risk amid rising multi-morbidity in high income countries. More than half of older adults now have at least two chronic diseases, the researchers said.
Lead author Dr Severine Sabia said: “This is proving to be a major challenge for public health, as multi-morbidity is associated with high healthcare service use, hospitalisations and disability." Sabia said sleep of 7-8 hours a night is recommended, as previous studies have associated durations above or below this with individual chronic diseases.
