Association between C-Reactive Protein and Metabolic Syndrome in Korean Adults

The prevalence of metabolic syndrome (MetS) is increasing, and obesity, insulin resistance, and inflammation are the known risk factors. However, results of previous studies regarding the relationship between MetS and inflammation have not been consistent. This study aimed to identify the associations between C-reactive protein (CRP) and MetS and its components in obese and non-obese men and women.

This was a cross-sectional study based on the 6th Korea National Health and Nutrition Examination Survey (2015), and a nationally representative sample of 3,013 Korean adults aged 40-78 years were included. Those with cardiovascular disease, cancer, CRP level >10 mg/L, white blood cell count >10,000/mm3 , chronic kidney disease, and lung/liver disease were excluded.

Approximately 11.0%, 50.0%, 8.4%, and 48.8% of non-obese men, obese men, non-obese women, and obese women presented with MetS (P<0.001), respectively. In all four groups, those who presented with MetS or its components showed a higher high-sensitivity (hs-CRP) average than those without. Multivariate regression analysis showed the increased risk of developing MetS with higher quartiles of hs-CRP level in obese (3rd and 4th quartiles: odds ratios [ORs], 3.87 and 2.57, respectively) and non-obese women (4th quartile: OR, 2.63). The different components also showed increased ORs in the four groups. However, no statistically significant trend in the relationship was found in men.

Low-grade inflammation may increase the risk of MetS in Korean women independent of adiposity. However, due to the cross-sectional design of the present study, further studies must be conducted to identify the causal relationship between inflammation and metabolic disorders.