Back pain and depression have been strongly correlated across numerous studies, often causing diagnostic and treatment challenges for practitioners attempting to address one or both problems. A new study, however, suggests that genetics may explain a large portion of that correlation.
Marina B. Pinheiro, of the University of Sydney, Australia, and colleagues used data from the Murcia Twin Registry in Spain to look at incidences of low back pain and depression in over 2,000 twins. Such twin studies are often used to clarify associations among health conditions, since it is easier to isolate genetic and environmental contributing factors.
The researchers found that when the participants were analyzed as individuals, the odds of back pain were increased by a factor of 1.6 when the individuals experienced depression. The connection actually strengthened when the researchers looked at pairs of dizygotic, or non-identical, twins (who share half of their genetic information).
But the association vanished altogether when the researchers looked at pairs of monozygotic, or identical, twins using more sophisticated statistical analyses; essentially, controlling for genetic and familial factors allowed the researchers to conclude that the relationship between low back pain and depression is probably not a direct one, but rather influenced by genetics.
The researchers cautioned that it’s too early to say that genetic factors predispose people to developing both conditions. This is the first study of its kind to use twin data, and Pinheiro and colleagues recommended that a longer study with more follow-up be performed to confirm the findings.
The authors of the study also suggested that more work be done on the connection between back pain and anxiety.
The full article has been published in the March issue of the journal Pain, the official publication of the International Association for the Study of Pain.