Insomnia is a marker for increased risk of back pain, say University of Haifa researchers

University of HaifaDec 17 2014

Having trouble sleeping? Then you are nearly one-and-a-half times more likely to eventually suffer from back pain, according to a new study conducted by the University of Haifa.

"After controlling for a range of variables, including socioeconomic status and lifestyle issues, we came to the conclusion that insomnia is a marker for the increased risk of back pain, though the reverse is not the case," say researchers Dr. Maayan Agmon, of the University of Haifa's Cheryl Spencer Department of Nursing, and Dr. Galit Armon of the Department of Psychology. The study was conducted in cooperation with Prof. Shlomo Berliner and Prof. Itzhak Shapira of the Tel Aviv Sourasky Medical Center (Ichilov).

Back pain is a very common ailment: Between 60% to 80% of the adult population will suffer from it at some point in their lives. Moreover, back pain is the single most costly condition in terms of total workers' compensation costs; for example, in Europe, it accounts for 0.5%-2% of the gross domestic product. The reasons for back pain are varied, though experts say that some 90% of those suffering from it have no identifiable cause.

But some 50% of back-pain sufferers also complain of insomnia, which is defined as difficulty initiating and/or maintaining sleep, prolonged awakening during the night, or waking up too early in the morning for more than a one-month period. It is known that insomnia increases a person's sensitivity to pain and that those suffering from it are liable to suffer from spontaneous pain more often and with more intensity compared to others, but this study is the first to show a direct connection between insomnia and back pain.

The subjects of the study were self-reported healthy, working adults who come to Sourasky Medical Center for routine periodic health exams; a total of 2,131 people were examined between January 2003 and December 2011 at three different junctures. The subjects were an average of 46.2 years of age, with 15.8 years of schooling, who worked an average of 9.6 hours a day. The large scope of the study was one of its clear advantages, as were the heterogeneous sample, the fact that those with health problems were weeded out and not included in the final results, and the lengthy period over which the study was conducted.

Diagnosing the subjects' back pain was done using two criteria: Confirmation of the patient's medical record by a doctors' examination at least once during the previous 12 months, and interviews confirming consistency of back pain for at least three months. It was found that the chances of those suffering from insomnia to also suffer from back pain were nearly 150% greater than among those whose sleep was regular. Among women, the correlation between insomnia and back pain was even higher.

"This comprehensive study, that took place over such a long period of time, is the correct way to demonstrate the link between these two common medical phenomena," the researchers said. "We examined healthy, employed adults, over three periods of time. After controlling for variables like socioeconomic status, lifestyle, and more, we arrived at the conclusion that insomnia is a predicting factor for back pain, though the reverse is not the case.

"The reason for this is not yet known, but it's possible that the link between the two conditions stems from a third biological factor that we haven't yet succeeded in identifying," they continued. "One possible link is stress; people suffering from insomnia generally describe their lives as stressful, so it's almost certain that they would suffer from chronic restlessness that will increase muscle tension and reduce the number of micro-pauses in muscle activity, which leads to back pain."