Relationship between BMI and glomerular filtration rate in a large cohort initiating a weight loss program: differential contributions of fat mass, fat-free mass, and abdominal fat compartments

This research investigates how body composition and fat distribution influence kidney function in a cohort of 9,704 individuals starting a weight loss program. While BMI alone showed a negative association with glomerular filtration rate (GFR), this association disappeared after adjusting for body fat percentage. Further analysis revealed that fat mass is linked to reduced GFR, whereas fat-free mass and subcutaneous fat are associated with better kidney function. The study highlights the importance of analyzing fat compartments rather than relying on BMI alone to assess renal health risks.