Modic changes and interleukin 1 gene locus polymorphisms in occupational cohort of middle-aged men

According to recent systematic reviews, Modic changes are associated with low-back pain. However, their pathophysiology remains largely unknown. A previous study of Northern Finnish males implicated that IL1A and MMP3 polymorphisms play a role in type II Modic changes. The purpose of the current study was to examine the association of IL1 cluster polymorphisms with Modic changes amongst middle-aged men in Southern Finland. The final study sample consisted of 108 men from three different occupations, who underwent magnetic resonance imaging (MRI) with a 0.1 T-scanner. Six single nucleotide polymorphisms (SNP) in the IL1 gene cluster (IL1A c.1-889C > T; IL1B c.3954C > T; IL1RN c.1812G > A; IL1RN c.1887G > C; IL1RN c.11100T > C; IL1RN c.1506G > A) were genotyped with the SNP-TRAP method or by allele-specific primer extension on modified microarray. In all, 45 subjects had Modic changes at one or more disc levels. The presence of the minor allele of IL1A (c.1-889C > T) was associated with these changes (any Modic change p = 0.031, type II changes p = 0.036). The carriers of the T-allele had a 2.5-fold risk of Modic change and the association was independent of the other IL1 gene cluster loci studied. In addition, a minor haplotype, with a frequency of 7.5% in the study population, including the minor alleles of IL1A c.1-889C > T, IL1RN c.1812G > A, and IL1RN c.1506G > A, was significantly associated with Modic changes. This observation is in accordance with the previous finding from a different geographical area, and thus confirms the importance of the IL1A gene in the pathophysiology of Modic changes.