FokI as a genetic factor of intervertebral disc degeneration: A PRISMA-compliant systematic review of overlapping meta-analyses.

J Clin Neurosci. 2019 Feb;60:36-43. doi: 10.1016/j.jocn.2018.09.028. Epub 2018 Oct 9.

Pekala PAHenry BMTaterra DPiwowar MVikse JTubbs RSTomaszewski KA.


Abstract

The association of FokI (rs2228570), a polymorphism of the vitamin D receptor gene, with intervertebral disc degeneration (IDD) has been investigated in a multitude of studies. However, conflicting results of these studies led to emergence of several meta-analyses over the past few years. Despite the increased statistical power, these meta-analyses have failed to provide uniform and conclusive data on the relationship of FokI with IDD. The aim of this study was to present a comprehensive review based on the most up-to-date meta-analyses on the association of FokI with IDD. A comprehensive search of all major databases was conducted to identify meta-analyses investigating relation between FokI and IDD. No date or language restrictions were applied. The Jadad decision algorithm was utilized to evaluate included meta-analyses and identify the one providing the best evidence. A total of 7 meta-analyses (n = 2580 original patients), that included six to ten case control studies, analyzed the association of FokI polymorphism with IDD. The meta-analysis of the highest quality supported the notion that overall there is no statistically significant association between FokI polymorphism and IDD. However, the authors showed that Caucasians have a reduced risk of IDD and Hispanics have an increased risk of IDD in the dominant and dominant/homozygous/heterozygous models of FokI polymorphism. While currently there is no evidence of an association between FokI polymorphism and IDD in the general population, ethnic predisposition has been shown.

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KEYWORDS:

FokI; Intervertebral disc degeneration; Vitamin D receptor; rs2228570