Associations of metabolic factors, especially serum retinol-binding protein 4 (RBP4), with blood pressure in Japanese -the Tanno and Sobetsu study-

Excess secretion of various adipocyte-derived molecules has been linked with insulin resistance, obesity, diabetes, inflammation, atherosclerosis, and cardiovascular disease. Retinol-binding protein 4 (RBP4), one of the new adipocytokine, is recently reported to provide a link between insulin resistance and features of metabolic factors. Hypertension is one of the most influential risk factors among cardiovascular disease. We examined the relationship between systolic blood pressure (BP) levels and metabolic factors including homeostasis model assessment of insulin resistance (HOMA-R), high sensitivity C-reactive protein (hs-CRP), adiponectin, and RBP4. The subjects were 153 men aged 59 +/- 14 years and 224 women aged 57 +/- 14 years who had undergone medical check-ups in rural communities in 2007. Systolic BP was positively correlated with HOMA-R, hs-CRP and RBP4 but not with adiponectin in women. There was a positive significant relationship between serum RBP4 levels and blood pressure in women, but such a relationship was not found in men. Serum RBP4 levels were not correlated with HOMA-R in either men or women. Serum RBP4 levels negatively were correlated with estimated glomerular filtration rate (eGFR) in women but not in men. Multiple regression analysis revealed that serum RBP4 levels significantly were related to systolic BP independently of age, sex, body mass index (BMI), total cholesterol levels and eGFR. Our study showed that increased levels of RBP4 as well as HOMA-R and hs-CRP in women were significantly associated with increased levels of systolic BP.