A persistent lack of sleep will land you in an early grave.
That is the conclusion of a 40-year study examining the long-term effects of sleepless nights.
Persistent insomnia – for six years or more – was linked to a 58 per cent increased risk of death, scientists at the University of Arizona found.
It was also linked to higher levels of inflammation in the blood, which is linked to heart disease, diabetes, obesity, cancer, dementia and depression.
Insomnia – difficulty falling asleep, staying asleep, or waking too early – is a common medical complaint.
Chronic insomnia means disrupted sleep that occurs at least three nights per week and lasts at least three months.
The U.S. researchers analysed data from a long running respiratory study, the Tucson Epidemiological Study of Airway Obstructive Disease, which began in 1972 and has followed participants for decades.
They found that unlike intermittent insomnia, chronic insomnia that lasted for at least six years was associated with mortality.
They also found persistant insomnia was associated with greater levels of inflammation in the blood (measured by a biomarker in blood called C-reactive protein).
Previous studies had linked insomnia with death, but the underlying mechanism for why has still not been shown.
Dr Sairam Parthasarathy, lead author of the study, said: ‘An enhanced understanding of the association between persistence of insomnia and death would inform treatment of the at-risk population.’
‘We found that participants with persistent insomnia were at increased risk of dying due to heart and lung conditions independent of the effects of hypnotics, opportunity for sleep (as distinguished from sleep deprivation), sex, age and other known confounding factors.’
The study’s senior author, Dr Stefano Guerra, said: ‘Although there were higher levels of inflammation and steeper rises in inflammation in individuals with persistent insomnia when compared to those with intermittent or no insomnia, more research into other pathways by which persistent insomnia may lead to increased mortality needs to be explored.’
Such research could help predict outcomes in patients with insomnia, he added.
The study was published online in the American Journal of Medicine.