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Aggrecan Variable Number of Tandem Repeat Polymorphism and Lumbar Disc Degeneration: A Meta-analysis

Gu, Jiaao MD; Guan, Fulin MD; Guan, Guofa MD; Xu, Gongping MD; Wang, Xintao MD; Zhao, Wei; Ji, Ye MD; Yan, Jinglong MD

Spine:
doi: 10.1097/BRS.0000000000000012
Epidemiology
Abstract

Study Design. Data on the association between the ACAN (encoded for aggrecan core protein) variable number of tandem repeat (VNTR) polymorphism and lumbar disc degeneration are conflicting, so we performed a meta-analysis.

Objective. Aggrecan is involved in the shock absorbing function of the lumbar disc; we performed a meta-analysis to assess the association between ACAN VNTR and lumbar degeneration.

Summary of Background Data. To perform a meta-analysis, we searched for studies published until September 2012, using electronic databases (PubMed, EMBASE, and China National Knowledge Infrastructure). Eight studies involving 965 cases of lumbar disc degeneration and 982 control subjects were identified.

Methods. Assessment for eligibility and extraction of data were performed by 2 independent investigators. We extracted allele frequency for each study. We calculated the pooled odds ratios (ORs) and 95% confidence intervals (CI) to assess the strength of the association between the ACAN VNTR polymorphism and lumbar disc degeneration risk.

Results. Results from the allele model suggested an increased risk of lumbar disc degeneration for the shorter alleles carriers compared with the normal alleles and longer alleles (OR = 1.54, 95% CI: 1.04–2.30, P = 0.03). In subgroup analysis by ethnicity, significant increased risks were found among Asians with shorter alleles (OR=1.65, 95% CI: 1.17–2.33, P = 0.004).

Conclusion. Our results suggest an increased risk of shorter alleles compared with normal alleles and longer alleles against lumbar disc degeneration among populations especially among Asian descent. Such association may not be statistically significant in European populations.

Level of Evidence: N/A

In Brief

A meta-analysis was performed to investigate the association between aggrecan variable number of tandem repeat and lumbar disc degeneration. Eight studies were identified. Our result suggested an increased risk of shorter alleles compared with normal alleles and longer alleles against lumbar disc degeneration among populations, especially among populations of Asian descent.

Author Information

From the Department of The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, People's Republic of China.

Address correspondence and reprint requests to Jinglong Yan, MD, Department of The First Affiliated Hospital of Harbin Medical University, No. 23, Youzheng St, Nangang District, Harbin, Heilongjiang Province, People's Republic of China; E-mail: haerbinmed@yahoo.com.cn

Acknowledgment date: November 12, 2012. First revision date: March 25, 2013. Acceptance date: May 19, 2013.

The manuscript submitted does not contain information about medical device(s)/drug(s).

Educational Commission of Heilongjiang Province, China (No. 12511280), funds were received to support this work.

No relevant financial activities outside the submitted work.

© 2013 by Lippincott Williams & Wilkins