J A Harvey1, K D Hill, C Y Pak. 1. Center in Mineral Metabolism and Clinical Research, University of Texas, Southwestern Medical Center, Dallas, USA.
Abstract
STUDY OBJECTIVE: To compare urinary biochemical risk factors among stone-forming patients in the Southeast (SE) or "stone belt" versus four other regions of the United States. DESIGN: Prospective biochemical survey for regional comparisons. SETTING: Referral-based nephrolithiasis clinics, urologists, nephrologists, and family practitioners. PATIENTS: Consecutive sample of 3473 stone-forming patients who submitted 24-hour urine collections for biochemical analyses of stone-forming risk factors. INTERVENTIONS: None. Subjects taking medication known to interfere with stone-forming risk factors were deleted from the final data compilation. MEASUREMENTS AND MAIN RESULTS: Overall, the mean values for each urinary parameter spanned a narrow range without significant difference between the five regions. Among "metabolic" factors, 40% in the SE had hypercalciuria (> 6.25 mmol/d), compared to 35%-43% in other regions, and hyperuricosuria (> 4.2 mmol/d) was found in 16% in the SE versus 17%-19% elsewhere. Among "environmental" factors, low urine volume ( < 2 L/d) was found in 77% patients in the SE compared to 69%-78% elsewhere, and high sodium was encountered in 27% in the SE versus 24%-29% elsewhere. No differences were noted in occurrence of other abnormal risk factors: hyperoxaluria, hypocitraturia, low pH, high sulfate, high phosphorus, or low magnesium. CONCLUSIONS: Despite expected regional differences in nutritional and environmental influences, the results of this study showed a striking similarity in urinary biochemical risk factor profiles of stone-formers in all five regions of the United States.
STUDY OBJECTIVE: To compare urinary biochemical risk factors among stone-forming patients in the Southeast (SE) or "stone belt" versus four other regions of the United States. DESIGN: Prospective biochemical survey for regional comparisons. SETTING: Referral-based nephrolithiasis clinics, urologists, nephrologists, and family practitioners. PATIENTS: Consecutive sample of 3473 stone-forming patients who submitted 24-hour urine collections for biochemical analyses of stone-forming risk factors. INTERVENTIONS: None. Subjects taking medication known to interfere with stone-forming risk factors were deleted from the final data compilation. MEASUREMENTS AND MAIN RESULTS: Overall, the mean values for each urinary parameter spanned a narrow range without significant difference between the five regions. Among "metabolic" factors, 40% in the SE had hypercalciuria (> 6.25 mmol/d), compared to 35%-43% in other regions, and hyperuricosuria (> 4.2 mmol/d) was found in 16% in the SE versus 17%-19% elsewhere. Among "environmental" factors, low urine volume ( < 2 L/d) was found in 77% patients in the SE compared to 69%-78% elsewhere, and high sodium was encountered in 27% in the SE versus 24%-29% elsewhere. No differences were noted in occurrence of other abnormal risk factors: hyperoxaluria, hypocitraturia, low pH, high sulfate, high phosphorus, or low magnesium. CONCLUSIONS: Despite expected regional differences in nutritional and environmental influences, the results of this study showed a striking similarity in urinary biochemical risk factor profiles of stone-formers in all five regions of the United States.
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NASA Discipline Number 18-10; NASA Discipline Regulatory Physiology; NASA Program Biomedicine; Non-NASA Center