Kidney function and sarcopenia in the United States general population: NHANES III

Background/Aims: It is not known whether sarcopenia is associated with levels of kidney function in community-dwelling adults. Methods: Subjects were adult Third National Health and Nutrition Examination Survey participants in whom bioimpedance was performed (n = 13,770). Class I sarcopenia was defined as a skeletal mass index of 1-2 standard deviations below and class II sarcopenia as <2 standard deviations below young adult values. Results: A monotonic association existed between increasing sarcopenia prevalence and declining glomerular filtration rate: ≥90 ml/min/1.73 m², 22.8% class I, 3.8% class II sarcopenia; 60-89 ml/min/1.73 m², 33.6% class I, 5.3% class II sarcopenia, and <60 ml/min/1.73 m², 50.7% class I, 9.4% class II sarcopenia (p < 0.0001). This association dissipated when adjustment was made for older age and more comorbidity. Multivariate associations (p < 0.05) of sarcopenia and chronic kidney disease included: older age; low income-to-poverty ratio; overweight; lack of exercise; low carbohydrate, fat and protein intake; hypercalcemia; low 25-hydroxy-vitamin D₃; higher diastolic blood pressure, and insulin resistance. Conclusion: Sarcopenia is common in community-dwelling adults with chronic kidney disease. Although causality cannot be assumed, several associations may be susceptible to intervention.