Link Between Low Back Pain and Depression Prevalent in Twins

Low back pain (LBP) and depression may be linked, according to findings from a study about twins which were published in the journal PAIN.

Researchers from The University of Sydney studied 2,148 twins from the Murcia Twin Registry in Spain in order to evaluate whether symptoms of depression are associated with LBP after adjusting for various factors. The twins were instructed to answer questions about lifetime experience with LBP and symptoms of depression. After a series of statistical analyses, the researchers clarified the contributions of genetic factors and early shared environmental and developmental factors that could have contributed to the experience of LBP.

The researchers determined there was a significant association between LBP and symptoms of depression. The initial analysis, which looked at the participants as individuals, demonstrated that the odds for having LBP were about 1.6 times higher for those participants who also experienced symptoms of depression and anxiety.

However, for twin pairs, which takes into account genetic and familial factors, the relationship between LBP and symptoms of depression remained significant, the researchers said. There was a 1.7 increase in odds. The odds increased to 2.3 times higher when the researchers analyzed only fraternal (dizygotic) twins. Monozygotic twins did not share associations between LBP and symptoms of depression, which the researchers attributed to non identical twins having “confounding” effects of common genetic factors which influence both conditions. The researchers believe that the neurotransmitters serotonin and norepinephrine might be affected from both of the conditions, LBP and depression.

“It still remains unclear whether common genetic factors predispose people to develop both low back pain and depression,” wrote Marina B. Pinheiro, MSc, and colleagues. The authors believe that further studies — especially those done with twins – may be able to dictate the link between LBP and symptoms of depression more concretely.

Prior research has indicated that a consistent relationship between LBP and depression exists, which may influence and complicate diagnoses and or treatment plans. This study was the first to examine the relationship between depression and LBP using data collected from twins to control for genetic and familial factors, a press release noted.