Student Use of the Washington State Twin Registry: An Analysis of Low Back Pain and Body Mass Index in Monozygotic and Dizygotic Twins

Primary author: Andrew Liechty
Faculty sponsor: Glen Duncan

Primary college/unit: Elson S. Floyd College of Medicine
Campus: Everett


In cohort studies, it can often be difficult to separate the question of nature vs nurture in the development of a particular disease. For this, Monozygotic twins (i.e. identical twins) allow us a convenient model to analyze various outcomes of interest between two individuals as they control for the genetic aspects. Students at WSU have access to the Washington State Twin Registry which contains a database of Monozygotic and Dizygotic Twin pairs that have answered questionnaires about health, education, and income for many years. I analyzed the relationship between low back pain and body mass index. I hypothesized that an increase in body mass index would lead to an increase in low back pain. We found that there was not a step wise increase in BMI and LBP. In fact, in monozygotic twins who were discordant for BMI (one normal weight and one obese) there was no statistical difference in LBP. We did find however, that there may be a genetic link between the two. We also found that Moderate to Vigorous Physical Activity is associated with LBP, however these may also be linked through a common genetic element. The Washington State Twin Registry is an untapped resource for undergraduate, graduate, and professional students as it allows us to account for genetics while analyzing a variety of factors.