Racial Differences in Serum Adipokine and Insulin Levels in a Matched Osteoarthritis Sample: A Pilot Study.

Background. In an attempt to correlate biomarkers with disease, serum-based biomarkers often are compared between individuals with osteoarthritis (OA) and control subjects. However, variable results have been reported. Some studies have suggested an association between certain adipokines and insulin and OA. We know that there are racial differences in OA prevalence and incidence, and from general population-based studies, those of Asian race consistently demonstrate a unique adipokine/insulin serum concentration profile as compared to Caucasians. Whether similar racial differences exist within OA samples is unknown and may have implications for selecting appropriate controls in comparative studies. Methods. Serum levels of adipokines, leptin, and adiponectin, along with insulin, were determined by ELISA in patients scheduled for total hip or knee replacement surgery for OA. Fifteen Asian patients were matched 1 : 1 on age (+/- 2 years), gender, body mass index (+/- 1.5 kg/m(2)), and surgical joint with Caucasian patients. Differences in serum concentrations were tested using paired t-tests. Results. Serum leptin and insulin levels were significantly higher in Asians compared to Caucasians (p < 0.05). While serum adiponectin levels were lower among Asians, the difference did not reach statistical significance (p = 0.12). Conclusion. Findings from this work suggest that when studying serum biomarker concentrations in OA versus controls, race may be an important factor to consider. Our findings warrant confirmation in larger studies.