The interaction between aggrecan gene VNTR polymorphism and obesity in predicting incident symptomatic lumbar disc herniation

Abstract

An association between aggrecan gene variable number of tandem repeats polymorphism (VNTR) and symptomatic lumbar disc herniation (LDH) has been reported in Chinese Han of Northern China, and obesity had previously been suspected of causing severe LDH. However, the interaction between aggrecan VNTR and obesity in symptomatic LDH has not been well studied. To examine the interaction between aggrecan VNTR and obesity in the susceptibility of symptomatic LDH, 259 participants participated in this study and donated a blood sample. The disease group comprised 61 patients already diagnosed with symptomatic LDH. The control group consisted of 198 healthy blood donors without symptoms of LDH who were not diagnosed with LDH. The aggrecan gene VNTR region was analyzed using polymerase chain reaction. The data indicated that between the two groups, participants carrying one or two alleles ≤25 repeats who were non-obese people showed a 1.057-fold increase in risk for symptomatic LDH (p = 0.895, changing the number of repeat alleles to <25 repeats alone did not demonstrably change the risk of LDH), and participants carrying two alleles >25 repeats who were obese people showed an 1.061-fold higher risk (p = 0.885, adding obesity to the mix alone did not demonstrably increase the risk of LDH), while participants carrying one or two alleles ≤25 repeats who were obese people showed a 4.667-fold increase in risk for symptomatic LDH (p = 0.0003, adding obesity plus changing the repeat allele number significantly increased the risk of LDH by 4.667). Overall, the findings suggest an underlying interaction between aggrecan VNTR and obesity in symptomatic LDH.