Sedentary behavior and estimated nephron number in middle-aged and older adults with or without chronic kidney disease

Keisei Kosaki, Kanako Takahashi, Masahiro Matsui, Masaki Yoshioka, Shoya Mori, Natsumi Nishitani, Ai Shibata, Chie Saito, Makoto Kuro-o, Kunihiro Yamagata, Koichiro Oka, Seiji Maeda*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Background: Excessive sedentary behavior may contribute to the pathogenesis of chronic kidney disease (CKD). The nephron index is a novel methodology for non-invasively estimating the number of functional nephrons, under the assumption that serum fibroblast growth factor 23 (FGF23) concentrations should correlate with phosphate excretion per nephron. The purpose of this study was to investigate the cross-sectional associations between daily sedentary time and the nephron index in middle-aged and older adults with or without CKD. Methods: The daily time spent in sedentary behavior was assessed using a tri-axial accelerometer in 294 participants (182 non-CKD adults and 112 CKD patients). The nephron index value was calculated by measuring blood and spot urine phosphate and creatinine, together with serum FGF23 concentrations and estimated glomerular filtration rate. Results: We observed that advancing age and CKD were associated with a progressive decrease in the nephron index value. Additionally, CKD patients with more sedentary time also had a greater nephron index decrease compared to those with less sedentary time (P < 0.05). Multiple linear regression analysis confirmed the independent association between sedentary time and the nephron index after adjusting for age, sex, presence of CKD, overweight/obesity, medication use, and total wear time (β = −0.13, P = 0.035). Conclusions: These cross-sectional findings suggest that age- or CKD-related decreases in the estimated nephron number (that is, the nephron index) may be accelerated by increased sedentary behavior.

Original languageEnglish
Article number111531
JournalExperimental Gerontology
Publication statusPublished - 2021 Oct 15


  • Fibroblast growth factor 23
  • Functional nephron number
  • Phosphate
  • Sedentary time

ASJC Scopus subject areas

  • Biochemistry
  • Ageing
  • Molecular Biology
  • Genetics
  • Endocrinology
  • Cell Biology


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