β-Carotene Status Is Associated with Inflammation and Two Components of Metabolic Syndrome in Patients with and without Osteoarthritis

This study was conducted to investigate the β-carotene status in osteoarthritis (OA) patients and examine its relationships with the risk of inflammation and metabolic syndrome. OA patients were stratified by obesity based on body fat percentage (obese OA, n = 44; non-obese OA, n = 56), and sixty-nine subjects without OA or obesity were assigned as a non-obese control group. β-carotene, metabolic parameters, and inflammation status were assessed. Obese OA patients exhibited a significantly higher rate of metabolic syndrome (p = 0.02), abdominal obesity (p < 0.01), and lower β-carotene status (p < 0.01) compared with non-obese OA and non-obese controls. After adjusting for potential confounders, β-carotene status (≥0.8 µM) was significantly inversely correlated with the risk of metabolic syndrome (odds ratio = 0.27, p < 0.01), abdominal obesity (odds ratio = 0.33, p < 0.01), high blood pressure (odds ratio = 0.35, p < 0.01), hyperglycemia (odds ratio = 0.45, p < 0.05), and inflammation (odds ratio = 0.30, p = 0.01). Additionally, subjects who had a high β-carotene status with a low proportion of metabolic syndrome when they had a low-grade inflammatory status (p < 0.01). Obese OA patients suffered from a higher prevalence of metabolic syndrome and lower β-carotene status compared to the non-obese controls. A better β-carotene status (≥0.8 µM) was inversely associated with the risk of metabolic syndrome and inflammation, so we suggest that β-carotene status could be a predictor of the risk of metabolic syndrome and inflammation in patients with and without OA.