ArticleAmerican journal of physiology. Renal physiology2019
Mechanisms for falling urine pH with age in stone formers.
Article in American journal of physiology. Renal physiology, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 15 papers.
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15 citing papers in PubMed, 32 citations in OpenAlex.
- Effect of Bicarbonate on Net Acid Excretion, Blood Pressure, and Metabolism in Patients With and Without CKD: The Acid Base Compensation in CKD Study.American journal of kidney diseases : the official journal of the National Kidney Foundation · 2021Trial
- Urine organic anion increases with age and its effects on renal acid excretion vary with pKa.American journal of physiology. Regulatory, integrative and comparative physiology · 2025Article
- Controlled Fabrication of pH-Visualised Silk Fibroin-Sericin Dual-Network Hydrogels for Urine Detection in Diapers.Gels (Basel, Switzerland) · 2025Article
- Nephrolithiasis.Advances in kidney disease and health · 2024Review
- The role of age and sex in non-linear dilution adjustment of spot urine arsenic.BMC nephrology · 2024Article
- Urinary calculi composition and its correlation with sex, age, calculi site, urine pH and underlying diseases: a retrospective study.American journal of translational research · 2024Article
- Asymptomatic hyperuricaemia in chronic kidney disease: mechanisms and clinical implications.Clinical kidney journal · 2023Review
- Urinary Risk Profile, Impact of Diet, and Risk of Calcium Oxalate Urolithiasis in Idiopathic Uric Acid Stone Disease.Nutrients · 2023Article
- Association between aortic calcification and the presence of kidney stones: calcium oxalate calculi in focus.International urology and nephrology · 2022Article
- Impact of age and renal function on urine chemistry in patients with calcium oxalate kidney stones.Urolithiasis · 2021Article
- A Pilot Study of the Safety and Efficacy of Alkali Therapy on Vascular Function in Kidney Transplant Recipients.Kidney international reports · 2021Article
- Risk factors for high-dose methotrexate-induced nephrotoxicity.International journal of hematology · 2021Article
- Relative contributions of urine sulfate, titratable urine anion, and GI anion to net acid load and effects of age.Physiological reports · 2021Article
- Twenty-four-hour urine osmolality should be used in combination with other urine parameters in urolithiasis patients.International urology and nephrology · 2019Article
- Conditions Favoring Increased COVID-19 Morbidity and Mortality: Their Common Denominator and its Early Treatment.Missouri medicineReview
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Authors and funding
6 authors at 1 institution in 1 country.
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Abstract
One of the main functions of the kidney is to excrete an acid load derived from both dietary and endogenous sources, thus maintaining the pH of other fluids in the body. Urine pH is also of particular interest in stone formers, since it determines the presence of either calcium phosphate or uric acid content in stones. Others have noted in epidemiological studies a rise in incidence of low pH-dependent uric acid stones with age, coinciding with a decrease in the incidence of high pH-dependent phosphate stones. Taken together, these trends are suggestive of a longitudinal decline in urine pH in stone-forming patients, and, if true, this could explain the observed trends in stone incidence. We studied 7,891 stone formers, all of whom collected a 24-h urine sample and matching serum. Multivariate modeling revealed that urine pH did indeed fall with age and particularly between the ages of 20 and 50 yr old in both men and women. We sought to explain this trend through the inclusion of traditionally understood determinants of urine pH such as urinary buffers, estimates of glomerular filtration, and dietary acid load, but these, taken together, accounted for but a small fraction of the pH fall. Gastrointestinal anion absorption was the strongest predictor of urine pH in all age groups, as we have previously reported in middle-aged normal men and women. However, we found that, despite a decreasing urine pH, gastrointestinal anion absorption increased monotonically with age. In fact, after adjustment for gastrointestinal anion absorption, urine pH declined more markedly, suggesting that bicarbonate-producing anion absorption is regulated in a manner that offsets the decline of urine pH.
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