Objective: To investigate the interrelationships among smoking, protein tyrosine phosphatase non-receptor 22 (PTPN22) R620W (rs2476601) genotype, and anticitrullinated peptide antibody (ACPA) status; and among smoking, PTPN22 R620W genotype, and presence of bone erosions overall and separately by ACPA status in patients with rheumatoid arthritis (RA).
Methods: Six studies totaling 2680 patients with RA were included in a Mantel-Haenszel fixed-effects metaanalysis investigating ACPA status and up to 8 studies totaling 3172 patients with RA were included in a Mantel-Haenszel fixed-effects metaanalysis investigating presence of erosive damage.
Results: Evidence was found for an increase in the odds of ACPA positivity for ever smoking (OR 1.56, 95% CI 1.28-1.90, p = 8.5 × 10(-6)), carriage of at least 1 of the PTPN22 risk alleles (OR 1.50, 95% CI 1.13-2.00, p = 5.5 × 10(-3)) and both ever smoking and carriage of at least 1 of the PTPN22 risk alleles (OR 2.22, 95% CI 1.69-2.91, p = 8.3 × 10(-9)). There was no evidence of an association between presence of erosive damage and smoking status or carriage of PTPN22 risk alleles when analyzed overall or separately by ACPA status.
Conclusion: This metaanalysis indicates that both smoking and the PTPN22 risk allele are associated with the risk of ACPA positivity. There was insufficient evidence to establish a relationship in either direction between PTPN22 and smoking with erosive damage, despite evidence that ACPA positivity is associated with erosive damage.