Hip osteoarthritis susceptibility is associated with IL1B −511(G>A) and IL1 RN (VNTR) genotypic polymorphisms in Croatian caucasian population

Among the predisposing factors to osteoarthritis (OA), a frequent destructive joint disease, is the complex genetic heritage including the interleukin‐1 family members like the IL1β (IL1B) and the IL1 receptor antagonist (IL1RN) genes. The aim of this study was to investigate allelic and genotypic frequencies of the IL1B gene single nucleotide polymorphism (SNP) at −511(G>A) and the variable number tandem repeat (VNTR) in the IL1RN gene in a Croatian Caucasian population of hip OA (HOA) cases and healthy controls. A total of 259 HOA patients with total hip replacement (THR) and 518 healthy blood donors as controls were genotyped for IL1B gene SNP −511(G>A) and the VNTR in the IL1RN gene associated with HOA. The genotype G/A (1/2) at IL1B was significantly associated with the protection of the HOA (p < 0.036, OR = 0.72, 95% CI = 0.52–0.99). The genotype G/G (1/1) had only a trend towards the susceptibility (p = 0.053, OR = 1.35, 95% CI = 0.98–1.86) to disease. None of the haplotypes IL1B −511(G>A) and IL1RN (VNTR) were found associated with the HOA. The haplotype 1–2 at these loci had only a trend to susceptibility (p = 0.065). Haplotype 1–3 had a significant male bias in diseased. Furthermore, genotype comprising 2–1/2–2 haplotypes was found significantly associated with predisposition to HOA (p = 0.027, OR = 2.23, 95% CI = 1.03–4.88), whereas genotype 1–1/2–2 with protection to disease (p = 0.028, OR = 0.65, 95% CI = 0.43–0.97). Our findings suggest that HOA in Croatian population might have a different genetic risk regarding the IL1 locus than has been reported for other Caucasian populations previously.