Urine specific gravity and water hardness in relation to urolithiasis in persons with spinal cord injury

Abstract

Study design: A matched case-control study. Objectives: To clarify the in¯uence of urine speci®c gravity and drinking water quality on the formation of urinary stones in persons with spinal cord injury (SCI). Setting: A rehabilitation center within a university hospital. Methods: Between 1992 and 1998, 63 stone cases (31 kidney, 27 bladder, and ®ve both) and 289 age-duration-matched controls were recruited from a cohort of SCI patients enrolled in an on-going longitudinal study. Data on urine speci®c gravity and other characteristics of study participants were retrieved from the database and medical charts. Community water supply information was provided by the Alabama Department of Environmental Management. Multivariable conditional logistic regression analysis was performed to evaluate the association with stone formation. Results: SCI individuals who had urinary stones were more likely than control subjects to use indwelling catheters and have decreased renal function. The occurrence of stones was not signi®cantly related to gender, race, severity of injury, urinary tract infection, nor urine pH. After controlling for the potential confounding from other factors, a continuously increasing stone occurrence with increasing speci®c gravity was observed (P=0.05); this association was stronger for kidney (odds Ratio [OR]=1.8 per 0.010 g/cm 3 ) versus bladder stones (OR=1.2) and for recurrent (OR=2.0) versus ®rst stones (OR=1.5). Increased water hardness was not signi®cantly associated with a decreased stone occurrence. Conclusions: Study results suggest that maintaining urine speci®c gravity below a certain level might reduce the occurrence of urinary stones. This could be easily achieved by using a dipstick for self-feedback along with appropriate¯uid intake. For persons with SCI who are at an increased risk of a devastating stone disease, this prophylactic approach could be very cost-eective; however, this requires further con®rmation. Spinal Cord (2001) 39, 571 ± 576Keywords: spinal cord injury; calculi; speci®c gravity; hardness IntroductionUrinary stone disease is a frequent complication of spinal cord injury (SCI). It has been estimated that within 8 years after injury, approximately 7% of SCI patients would develop their ®rst kidney stones, 1 whereas 36% would have bladder stones.2 Urinary calculi can lead to obstruction, sepsis, deterioration of renal function, and even loss of the aected kidney. 3,4 An eective method to prevent stones is necessary to alleviate the threat, which they pose to the health and welfare of many SCI survivors.The high stone incidence in the SCI population has been thought to be attributable to immobilization hypercalciuria and an increased susceptibility to urinary tract infection (UTI).1 Most injury-related determinants of urinary stones, including years since injury, severity of injury, and methods of bladder management, may re¯ect one or both of these pathways. However, because UTI is much more common than urinary stones in persons with SCI, infection may be a necessary compon...

Fluid and Sodium Balance of Elite Wheelchair Rugby Players

“…Furthermore, SCI individuals may drink more because of the high prevalence of urinary tract infections and kidney and bladder stones reported in this population (Shekelle, Morton, Clark, Pathak, & Vickrey, 1999). The higher incidence of urinary tract infections has led to advice to increase fluid intakes and promote euhydration among the SCI population (Chen, Roseman, Funkhouser, & DeVivo, 2001). However, currently there is no definitive research showing an association between USG and the risk of bladder or kidney stones for those with a spinal-cord injury (Chen et al, 2001).…”

“…The higher incidence of urinary tract infections has led to advice to increase fluid intakes and promote euhydration among the SCI population (Chen, Roseman, Funkhouser, & DeVivo, 2001). However, currently there is no definitive research showing an association between USG and the risk of bladder or kidney stones for those with a spinal-cord injury (Chen et al, 2001). Despite the lack of concrete evidence, it is possible the players in the current study regularly ingested fluid throughout the day in an attempt to attenuate the risk of urinary tract infections.…”

Dietary NaCl Does Not Affect Blood Pressure in Healthy Cats

“…[3][4][5] This could potentially reduce calcium oxalate and stuvite urine saturation, as suggested by some preliminary studies 3,4 and observations in human studies. 6,7 Along with the potential beneficial effects of increased dietary salt on patients with FLUTD, potential adverse effects must be considered as well. Increased salt intake has been associated with increased arterial blood pressure in both humans and laboratory animals.…”

Urine: Waste product or biologically active tissue?

“…Much like how water quality may affect the ecologic health of a body of water, urine quality is proposed as a potential factor contributing to bladder health. Specifically, the authors define urine quality as the biological, chemical, and physical characteristics of urine, including the microbiota, [18][19][20] cells, 21 exosomes, [22][23][24][25] pH, metabolites, 6,26 proteins, 27,28 and specific gravity [29][30][31] (among others). These features might interact in complex ways with one another and the bladder and/or kidney to potentially affect health.…”