APOA1 and rheumatoid arthritis: In older (>50.19 years) individuals, only smoking (OR = 1.74 (1.24–2.45)) was significantly associated with increased risk of future RA, whereas in younger individuals the significant factors were elevated ApoB/ApoA1 ratio (OR = 1.39 (1.00–1.93)), BMI ≥ 25.0 (OR = 1.45 (1.04–2.02)) and smoking (OR = 2.11 (1.51–2.95)).