Article

Higher Biomarker-Calibrated Protein Intake Is Not Associated with Impaired Renal Function in Postmenopausal Women

Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
Journal of Nutrition (Impact Factor: 4.23). 06/2011; 141(8):1502-7. DOI: 10.3945/jn.110.135814
Source: PubMed

ABSTRACT With aging, renal function tends to decline, as evidenced by reduced glomerular filtration rate. High-protein intake may further stress the kidneys by causing sustained hyperfiltration. To investigate whether dietary protein is associated with impaired renal function, we used data from 2 nested case-control studies within the Women's Health Initiative Observational Study (n = 2419). We estimated protein intake using a FFQ and estimated glomerular filtration rate (eGFR) from cystatin C. To account for the original study designs, inverse probability weights were applied. Self-reported energy and protein were calibrated using biomarkers of energy and protein intake. Associations between protein intake and renal function were estimated by weighted linear and logistic regression models. Average calibrated protein intake (mean ± SD) was 1.1 ± 0.2 g/(kg body weight·d).Twelve percent (n = 292) of women had impaired renal function. The odds of impaired renal function, defined as eGFR <60 mL/(min·1.73m(2)), was not associated with calibrated protein intake. When eGFR was modeled continuously, there was no association with calibrated protein when protein was expressed in absolute (g/d) or relative to energy (protein % energy/d), but protein relative to body weight [g/(kg body weight·d)] was associated with higher eGFR. There was no evidence for effect modification by age, BMI, or general health status. These data suggest higher protein intake is not associated with impaired renal function among postmenopausal women without a diagnosis of chronic kidney disease.

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    • "Baseline protein intake was not related to GFR. This is in agreement with results, e.g., from the Women's Health Initiative Observational Study, which suggest that higher protein intake is not associated with impaired renal function among postmenopausal women without a diagnosis of chronic kidney disease [32]. Results from the Nurses' Health study also indicate that high protein intake is not associated with renal function decline in women with normal renal function. "
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