t this relationship is lost in diabetic patients and UASFs. Background Uric acid (UA) nephrolithiasis affects approximately 10% of kidney stones, with a greater preponderance among patients with obesity and diabetes mellitus (DM). UA lithogenicity is driven by abnormally acidic urine pH. Distinguishing the contribution of intrinsic (e.g., body adiposity) versus external (e.g., dietary) factors to UA stone propensity is challenging because of uncontrolled diets in outpatients in previously published studies. Methods This compilation of metabolic studies with body composition examined by dual-energy x-ray absorptiometry scan and blood and urine biochemistry collected under a controlled metabolic diet was conducted across three distinct populations: 74 UA stone formers (UASF group), 13 patients with type 2 DM without kidney stones (DM group), and 51 healthy volunteers (HV group). Results Compared with HVs, both UASFs and patients with DM exhibited higher levels of net acid excretion (NAE) and significantly lower urine pH and lower proportion of NAE excreted as ammonium (NH4+/NAE), all under controlled diets. UASFs exhibited significantly lower NH4+/NAE compared with patients with DM. UASFs also showed higher total body and truncal fat compared with HVs. Among the HVs, lower NH4+/NAE ratio correlated with higher truncal and total fat. However, this association was abolished in the UASF and DM groups who exhibit a fixed low NH4+/NAE ratio across a range of body and truncal fat. Conclusions The findings suggest a dual defect of diet-independent increase in acid production and impaired kidney NH4+ excretion as major contributors to the risk of UA stone formation. There is an inverse physiologic association between body fat content and NH4+/NAE in HVs, whereas NH4+/NAE is persistently low in UASFs and patients with DM, regardless of body fat, representing pathophysiology....

中文翻译：

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尿酸结石形成者和 2 型糖尿病患者的脂肪分布和尿石症风险参数


t 这种关系在糖尿病患者和 UASF 中丢失。背景尿酸 （UA） 肾结石影响约 10% 的肾结石，肥胖和糖尿病 （DM） 患者更为明显。UA 成石性是由异常酸性尿液 pH 值驱动的。区分内在因素（例如身体肥胖）和外部因素（例如饮食因素）对 UA 结石倾向的影响具有挑战性，因为在先前发表的研究中，门诊患者的饮食不受控制。方法 在三个不同的人群中进行了代谢研究，通过双能 X 射线吸收测定法扫描检查身体成分，并在受控代谢饮食下收集血液和尿液生化分析：74 名 UA 结石形成者 （UASF 组），13 名无肾结石的 2 型 DM 患者 （DM 组），和 51 名健康志愿者 （HV 组）。结果 与 HVs 相比，UASFs 和 DM 患者均表现出更高水平的净酸排泄 （NAE） 和显著降低的尿 pH 值和较低的 NAE 以铵态氮 （NH4+/NAE） 形式排泄的比例，均在控制饮食下。与 DM 患者相比，UASF 的 NH4 + / NAE 显着降低。与 HV 患者相比，UASF 还表现出更高的全身脂肪和躯干脂肪。在 HVs 中，较低的 NH4 +/NAE 比率与较高的躯干和总脂肪相关。然而，这种关联在 UASF 和 DM 组中被消除，他们在一系列身体和躯干脂肪中表现出固定的低 NH4+/NAE 比率。结论 研究结果表明，不依赖饮食的酸产生增加和肾脏 NH4+ 排泄受损的双重缺陷是 UA 结石形成风险的主要因素。 HVs 中的体脂含量与 NH4+/NAE 之间存在负生理关联，而 NH4+/NAE 在 UASF 和 DM 患者中持续较低，无论体脂如何，都代表病理生理学。