New York, Dec 23 (IANS) You can literally lose sleep over discrimination as a new study has found that people who perceive more unfairness in daily life have higher rates of sleep problems.

"Discrimination is an important factor associated with sleep measures in middle-aged adults," according to the study by Sherry Owens of West Virginia University in the US, and colleagues. 

The research included 441 adults from a study of health and well-being in middle age and beyond (the MIDUS Study). The participants' average age was 47 years. 

Participants wore an activity monitor device for one week to gather data on objective sleep measures -- for example, sleep efficiency, calculated as the percentage of time spent in bed that the person was asleep. 

They also completed subjective sleep ratings -- for example, how often they had sleep problems.

Perceived experiences of discrimination were assessed using a validated "Everyday Discrimination Scale." 

For example, participants were asked how often they were treated with less courtesy or respect than others, or how often they were insulted or harassed.

Participants who perceived more discrimination had increased sleep problems, according to the study published in Psychosomatic Medicine: Journal of Biobehavioral Medicine.

Higher discrimination scores were associated with 12 per cent higher odds of poor sleep efficiency and a nine percent increase in the odds of poor sleep quality. 

Discrimination was also related to (objective) time spent awake after falling asleep and (subjective) overall sleep difficulties.

While poor sleep has previously been linked to higher perceived discrimination, the researchers said that the new study is the first to look at how discrimination affects both objective and subjective sleep measures.

"The findings support the model that discrimination acts as a stressor than can disrupt subjective and objective sleep," the study said.