The study was conducted by Jussi Vahtera, MD, of the Finnish Institute of Occupational Health in Helsinki, Finland.
It involved a population sample of 16,627 men and women with undisturbed sleep and 2,572 with disturbed sleep, all of whom participated in a five-year longitudinal observational cohort study.
According to the researchers, the degree of anxiety was measured by a general feeling of stressfulness and symptoms of hyperactivity at the onset of the study, with the occurrence of post-onset life events (i.e., death or illness in the family, divorce, financial difficulty and violence) and sleep disturbances measured at follow-up five years later.
The research found out that accountability to anxiety and negative life events are in accordance with sleep disorders.
The boffins found that among men liable to anxiety, the odds of sleep disturbances were 3.11 times higher for those who had experienced a severe life event within six months than for the others.
The men not liable to anxiety had odds of only 1.13 for sleep disturbances. For the men and women liable to anxiety, the odds ratio for sleep disturbance zero to six months after divorce was 2.05, with the corresponding ratio being 1.47 for those not liable to anxiety.
"This five-year follow-up showed that exposure to severe stressful events can trigger sleep disturbances in people with undisturbed sleep before the event. Those liable to anxiety before the event seemed to be at a higher risk of post-event sleep disturbances compared with those not liable to anxiety," said Dr. Vahtera.
The strength of this study is a study design that allowed the timing of pre-event predisposing traits and the occurrence of specific stressful events precipitating the onset of sleep disturbances. Control for a large number of potential confounding factors suggest that the observed associations were not explained by socioeconomic position, obesity, high alcohol intake or chronic medical conditions at study entry."
Experts recommend that adults get seven to eight hours of sleep each night for good health and optimum performance. Adolescents should sleep about nine hours a night, school-aged children between 10-11 hours a night and children in pre-school between 11-13 hours a night.
The research was published in the November 1 issue of the 'Sleep' Journal.