Adrien Bigot, Gaëlle Gusto, Nane Copin, Bénédicte Sautenet, Olivier Lantieri and Jean-Michel Halimi
Objective: Obesity and diabetes mellitus increase the risk of chronic renal disease. However, whether body mass index (BMI) and metabolic disturbances are associated with renal dysfunction and affect similarly albuminuria and estimated glomerular filtration rate (eGFR) are less clear. Hence, the aim of this study was to describe these associations in the general French population.
Methods: We realised a large cross-sectional study of 118,314 subjects aged ≥ 40 years undergoing a medical examination in 11 French regional health centers. Results: Renal dysfunction ((abnormal albuminuria (≥ 30 mg/g) and/or low eGFR (<60 ml/min/1.73m2)) was observed in 5.3% of subjects. There was a J-curve relationship between BMI and the risk of abnormal albuminuria: underweight (BMI<18.5 kg/m²: odds ratio: 2.12 [95% confidence interval: 1.55-2.83]), overweight (BMI 25-29.9: 1.36 [1.24-1.50]), and obese (BMI 30-34.9: 2.66 [2.39-2.97]; BMI 35-39.9: 4.14 [3.52-4.86]; BMI>40: 7.35 [5.89-9.15]) had a greater risk of abnormal albuminuria than subjects with normal weight. In contrast, the relationship between BMI - or other metabolic disturbances- and low eGFR was continuous. Metabolic disturbances increased the risk of abnormal albuminuria to a greater extent than the risk of abnormal eGFR. High fatty liver index and high calculated risk of developing diabetes were risk factors for both abnormal albuminuria and low eGFR.
Conclusion: There is a J-curve relationship between BMI and abnormal albuminuria, in contrast to the continuous association between other metabolic disturbances and abnormal eGFR. All metabolic disturbances are associated with abnormal albuminuria, but the association with abnormal eGFR is less clear, suggesting a stronger relationship with endothelial than renal dysfunction. Abnormal albuminuria and eGFR may precede the onset of diabetes.