Metabolic abnormalities, but not obesity, contribute to the mildly reduced eGFR in middle-aged and elderly Chinese

Background The role of obesity as a determinant of kidney dysfunction has not reached an agreement and the underlying reason may be due to the heterogeneity of obese phenotypes. The aim of the study was to explore the associations of different obese phenotypes with the change of estimated glomerular filtration rate (eGFR) and the roles of obesity and metabolic abnormalities in this association. Methods eGFR was calculated in 8,586 participants (≥40 years old). eGFR 60–90 mL/min/1.73 m 2 was defined as the mildly reduced eGFR. Multiple logistic regression analysis was used to determine odds ratios (ORs) for mildly reduced eGFR in the metabolically healthy obese (MHO), metabolically abnormal non-obese (MANO) and metabolically abnormal obese (MAO) groups, using the metabolically healthy non-obese (MHNO) subjects as the reference group. Meanwhile, the associations of body mass index (BMI), waist circumference (WC) and metabolic abnormalities (including hypertension, hyperglycemia and dyslipidemia) with the risk of mildly reduced eGFR were also investigated. Results The proportion of MHNO, MHO, MANO and MAO subjects was 8.3, 17.1, 10.1 and 64.5 %, respectively. Increased ORs were observed in MANO (OR 1.51, P = 0.014) and MAO (OR 1.47, P = 0.015) groups, after adjusting for age, gender, smoking, drinking, BMI and WC. When further adjusting for metabolic abnormalities, MANO (OR 1.24, P = 0.247) and MAO (OR 1.17, P = 0.366) subjects would not present increased risk of mildly reduced eGFR any more. Oppositely, fasting insulin (OR 1.03, P