Hung-Chieh Yeh1, Yu-Sheng Lin2, Chin-Chi Kuo3, Darcy Weidemann4, Virginia Weaver5, Jeffrey Fadrowski4, Alicia Neu6, Ana Navas-Acien7. 1. Kidney Institute and Division of Nephrology, Department of Internal Medicine, China Medical University Hospital and College of Medicine, China Medical University, Taichung, Taiwan. 2. Department of Environmental and Occupational Health, University of North Texas Health Science Center, Fort Worth, TX, USA. 3. Kidney Institute and Division of Nephrology, Department of Internal Medicine, China Medical University Hospital and College of Medicine, China Medical University, Taichung, Taiwan; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD, USA. 4. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Division of Nephrology, Department of Pediatrics, Johns Hopkins Medical Institutions, Baltimore, MD, USA. 5. Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD, USA. 6. Division of Nephrology, Department of Pediatrics, Johns Hopkins Medical Institutions, Baltimore, MD, USA. 7. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
Abstract
BACKGROUND: For many environmental chemicals, concentrations in spot urine samples are considered valid surrogates of exposure and internal dose. To correct for urine dilution, spot urine concentrations are commonly adjusted for urinary creatinine. There are, however, several concerns about the use of urine creatinine. While urine osmolality is an attractive alternative; its characteristics and determinants in the general population remain unknown. Our objective was to describe the determinants of urine osmolality and to contrast the difference between osmolality and creatinine in urine. METHODS: From the National Health and Nutrition Examination Survey (NHANES) (2009-2010), 10,769 participants aged 16 years or older with measured urine osmolality and creatinine were used in the analysis. Very dilute and very concentrated urine was defined as urine creatinine lower than 0.3g/l and higher than 3g/l, respectively. Linear and logistic regression analyses were performed to investigate the associations of interest. RESULTS: Urine osmolality and creatinine were highly correlated (Pearson correlation coefficient=0.75) and their respective median values were 648 mOsm/kg and 1.07 g/l. The prevalence of very dilute and very concentrated urine samples was 8.1% and 3.1%, respectively. Factors associated in the same direction with both urine osmolality and urine creatinine included age, sex, race, body mass index (BMI), hypertension, water intake, and blood osmolality. The magnitude of associations expressed as percent change was significantly stronger with creatinine than osmolality. Compared to urine creatinine, urine osmolality did not vary by diabetes status but was affected by daily total protein intake. Participants with chronic kidney disease (CKD) had significantly higher urine creatinine concentrations but lower urine osmolality. Both very dilute and concentrated urine were associated with a diverse array of sociodemographic, medical conditions, and dietary factors. For instance, females were approximately 3.3 times more likely to have urine over-dilution than male [the adjusted odds ratios (95% CI)=3.27 (2.10-5.10)]. CONCLUSION: Although the determinants of urine osmolality were generally similar to those of urine creatinine, the relative influence of socio-demographic and medical conditions was less on urine osmolality than on urine creatinine. Protocols for spot urine sample collection could recommend avoiding excessive and insufficient water intake before urine sampling to improve urine adequacy. The feasibility of adopting urine osmolality adjustment and water intake recommendations before providing spot urine samples for environmental biomonitoring merits further investigation.
BACKGROUND: For many environmental chemicals, concentrations in spot urine samples are considered valid surrogates of exposure and internal dose. To correct for urine dilution, spot urine concentrations are commonly adjusted for urinary creatinine. There are, however, several concerns about the use of urine creatinine. While urine osmolality is an attractive alternative; its characteristics and determinants in the general population remain unknown. Our objective was to describe the determinants of urine osmolality and to contrast the difference between osmolality and creatinine in urine. METHODS: From the National Health and Nutrition Examination Survey (NHANES) (2009-2010), 10,769 participants aged 16 years or older with measured urine osmolality and creatinine were used in the analysis. Very dilute and very concentrated urine was defined as urine creatinine lower than 0.3g/l and higher than 3g/l, respectively. Linear and logistic regression analyses were performed to investigate the associations of interest. RESULTS: Urine osmolality and creatinine were highly correlated (Pearson correlation coefficient=0.75) and their respective median values were 648 mOsm/kg and 1.07 g/l. The prevalence of very dilute and very concentrated urine samples was 8.1% and 3.1%, respectively. Factors associated in the same direction with both urine osmolality and urine creatinine included age, sex, race, body mass index (BMI), hypertension, water intake, and blood osmolality. The magnitude of associations expressed as percent change was significantly stronger with creatinine than osmolality. Compared to urine creatinine, urine osmolality did not vary by diabetes status but was affected by daily total protein intake. Participants with chronic kidney disease (CKD) had significantly higher urine creatinine concentrations but lower urine osmolality. Both very dilute and concentrated urine were associated with a diverse array of sociodemographic, medical conditions, and dietary factors. For instance, females were approximately 3.3 times more likely to have urine over-dilution than male [the adjusted odds ratios (95% CI)=3.27 (2.10-5.10)]. CONCLUSION: Although the determinants of urine osmolality were generally similar to those of urine creatinine, the relative influence of socio-demographic and medical conditions was less on urine osmolality than on urine creatinine. Protocols for spot urine sample collection could recommend avoiding excessive and insufficientwater intake before urine sampling to improve urine adequacy. The feasibility of adopting urine osmolality adjustment and water intake recommendations before providing spot urine samples for environmental biomonitoring merits further investigation.
Authors: Barbro Nermell; Anna-Lena Lindberg; Mahfuzar Rahman; Marika Berglund; Lars Ake Persson; Shams El Arifeen; Marie Vahter Journal: Environ Res Date: 2007-09-27 Impact factor: 6.498
Authors: Dana B Barr; Lynn C Wilder; Samuel P Caudill; Amanda J Gonzalez; Lance L Needham; James L Pirkle Journal: Environ Health Perspect Date: 2005-02 Impact factor: 9.031
Authors: Darcy Weidemann; Chin-Chi Kuo; Ana Navas-Acien; Alison G Abraham; Virginia Weaver; Jeffrey Fadrowski Journal: Environ Res Date: 2015-04-21 Impact factor: 6.498
Authors: Carolyn J Brooks; Steven L Gortmaker; Michael W Long; Angie L Cradock; Erica L Kenney Journal: Am J Public Health Date: 2017-07-20 Impact factor: 9.308
Authors: Jessie P Buckley; Stephanie M Engel; Joseph M Braun; Robin M Whyatt; Julie L Daniels; Michelle A Mendez; David B Richardson; Yingying Xu; Antonia M Calafat; Mary S Wolff; Bruce P Lanphear; Amy H Herring; Andrew G Rundle Journal: Epidemiology Date: 2016-05 Impact factor: 4.822
Authors: Hilary J Bethancourt; Zane S Swanson; Rosemary Nzunza; Tomas Huanca; Esther Conde; W Larry Kenney; Sera L Young; Emmanuel Ndiema; David Braun; Herman Pontzer; Asher Y Rosinger Journal: Am J Hum Biol Date: 2020-06-24 Impact factor: 1.937
Authors: Asher Y Rosinger; Hilary J Bethancourt; Abigail M Pauley; Celine Latona; Jason John; Alysha Kelyman; Krista S Leonard; Emily E Hohman; Katherine McNitt; Alison D Gernand; Danielle Symons Downs; Jennifer S Savage Journal: Eur J Nutr Date: 2021-07-03 Impact factor: 5.614