Is there a J-shaped relationship between the fatty liver index and risk of microalbuminuria in the general population?

Background: We investigated whether the fatty liver index (FLI), as a clinical indicator of hepatic fat accumulation based on body mass index, gamma-glutamyl-transferase, triglycerides, and waist circumference, has an association with microalbuminuria. Methods: We analyzed anthropometric and biochemical data from a nation-wide, population-based, cross-sectional study. A total of 1605 participants included were healthy native Korean 40 years or older and divided into quintiles according to their log-FLI and sex. Microalbuminuria was defined as urine albumin/creatinine ratio (UACR) between 30 and 300 mg/g. Results: Participants in higher quintiles of log-FLI were more obese and hypertensive and had greater glycemic exposure, poorer lipid profiles, and greater increases in log-UACR compared with lower quintiles. Linear regression analysis demonstrated that log-FLI was associated with systolic and diastolic blood pressure, body mass index, waist circumference, fasting plasma glucose, glycated hemoglobin, and log-UACR. In logistic regression adjusted for age, sex, body mass index, waist circumference, and fasting plasma glucose, the OR of microalbuminuria was elevated in quintile 1 (adjusted OR = 2.161, 95% CI = 0.453-10.31) and quintile 5 (adjusted OR = 6.387, 95% CI = 1.317-51.58), when compared to quintile 2. Conclusions: There appears to be a J-shaped association between FLI and UACR in healthy general population.