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.

中文翻译：

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患有或不患有慢性肾病的中老年人的久坐行为和估计的肾单位数量

背景

过度久坐行为可能导致慢性肾脏病 (CKD) 的发病机制。肾单位指数是一种用于非侵入性估计功能性肾单位数量的新方法，假设血清成纤维细胞生长因子 23 (FGF23) 浓度应与每个肾单位的磷酸盐排泄相关。本研究的目的是调查每日久坐时间与患有或不患有 CKD 的中老年人的肾单位指数之间的横断面关联。

方法

在 294 名参与者（182 名非 CKD 成人和 112 名 CKD 患者）中使用三轴加速度计评估了每天久坐行为所花费的时间。肾单位指数值是通过测量血液和尿液中的磷酸盐和肌酐以及血清 FGF23 浓度和估计的肾小球滤过率来计算的。

结果

我们观察到随着年龄的增长和 CKD 与肾单位指数值的逐渐降低有关。此外，与久坐时间较少的CKD患者相比，久坐时间较长的CKD患者肾单位指数下降幅度更大（P  < 0.05）。多元线性回归分析证实了在调整年龄、性别、CKD、超重/肥胖、药物使用和总佩戴时间后，久坐时间与肾单位指数之间的独立关联（β  = -0.13，P  = 0.035）。

结论

这些横断面研究结果表明，久坐行为的增加可能会加速估计肾单位数量（即肾单位指数）的年龄或 CKD 相关减少。