Hormonal treatment exposition and smoking were found to act with a protective effect against ACPA production (OR = 0.44, 95% CI 0.3, 0.7, P = 0.001) and early bone erosion (OR = 0.56, 95% CI 0.4-0.8, P = 0.003), respectively, and independently of HLADR and PTPN22 status