Lp(a) lipoprotein and lipids in patients with rheumatoid arthritis: serum levels and relationship to inflammation

Objectives Changes in lipid profiles, Lp(a) lipoprotein, and acute phase reactants are associated with early atherosclerosis in rheumatoid arthritis (RA). The associations of Lp(a) levels with atherosclerotic disorders, diabetes, RA, and renal diseases suggest that Lp(a) might be involved in autoimmune reactions.Methods Eighty-seven women with RA diagnosed according to American Rheumatism Association criteria (mean age 45.4±9.4 years) were recruited and 50 healthy women (mean age 44±10.7 years) included as a control group. Serum Lp(a), total cholesterol (TC), triglyceride (TG), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), and C-reactive protein levels were analyzed.Results In the RA and C groups, serum Lp(a) levels were 39.2±20.6 mg/dl and 14.8±9.7 mg/dl, respectively (P<0.001). The TC levels were 188.4±41.8 mg/dl and 185.3±19.3 mg/dl (P>0.05), TG levels were 124.5±50.1 mg/dl and 94.6±24.9 mg/dl (P<0.01), HDL-C levels were 40.0±7.4 mg/dl and 52.8±4.8 mg/dl (P<0.01), and LDL-C levels were 123.4±24.6 mg/dl and 113.3±21.1 mg/dl (P>0.05). While serum CRP levels showed a positive correlation with Lp(a), they correlated negatively with HDL-C levels (r=0.83 and P<0.0001, r=–0.49 and P<0.0001, respectively). It was meaningful that Lp(a) correlated negatively with serum HDL-C level (r=–0.36, P<0.001).Conclusions It is suggested that higher serum Lp(a), lower HDL-C, higher TG level, and a high ratio of TC/HDL-C might show high risk of atherosclerosis. Inflammation in RA may cause changes in HDL-C and Lp(a) metabolisms.