Jan Gerrit van der Stouwe1,2, Cristian Carmeli3, Stefanie Aeschbacher1,2, Tobias Schoen1,2, Philipp Krisai1,2, Giuditta Wenger1,2, Georg Ehret4, Belen Ponte5, Menno Pruijm6, Daniel Ackermann7, Idris Guessous8,9,10, Fred Paccaud3, Antoinette Pechère-Bertschi11, Bruno Vogt7, Markus G Mohaupt12, Pierre-Yves Martin5, Michel Burnier6, Martin Risch13,14, Lorenz Risch13,15,16, Murielle Bochud3, David Conen1,2,17. 1. Department of Medicine, University Hospital Basel, University of Basel, Basel, Switzerland. 2. Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland. 3. Institute of Social and Preventive Medicine, Lausanne University Hospital, Lausanne, Switzerland. 4. Department of Cardiology, Geneva University Hospitals, Geneva, Switzerland. 5. Department of Nephrology, Geneva University Hospitals, Geneva, Switzerland. 6. Service of Nephrology and Hypertension, University Hospital Lausanne, Lausanne, Switzerland. 7. University Clinic for Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. 8. Geneva University Hospitals, Unit of population epidemiology, Geneva, Switzerland. 9. Department of Ambulatory Care and Community Medicine, University of Lausanne and Department of Epidemiology, Lausanne, Switzerland. 10. Emory University, Atlanta, Georgia, USA. 11. Geneva University Hospitals, Hypertension Unit, Geneva, Switzerland. 12. Sonnenhofspital, Bern, Switzerland. 13. Labormedizinisches Zentrum Dr. Risch, Principality of Liechtenstein, Schaan, FL. 14. Division of Laboratory Medicine, Kantonspital Graubünden, Chur, Switzerland. 15. Division of Clinical Biochemistry, Medical University Innsbruck, Innsbruck, Austria. 16. Private University, Triesen, FL. 17. Population Health Research Institute, McMaster University, Hamilton, Canada.
Abstract
BACKGROUND: While the positive relationship between urinary sodium excretion and blood pressure (BP) is well established for middle-aged to elderly individuals using office BP, data are limited for younger individuals and ambulatory BP measurements. METHODS: Our analysis included 2,899 individuals aged 18 to 90 years from 2 population-based studies (GAPP, Swiss Kidney Project on Genes in Hypertension [SKIPOGH]). Participants with prevalent cardiovascular disease, diabetes, or on BP-lowering treatment were excluded. In SKIPOGH, 24-hour urinary sodium excretion was used as a measure of sodium intake, while in GAPP it was calculated from fasting morning urinary samples using the Kawasaki formula. Multivariable linear regression models were used to assess the relationships of 24-hour urinary salt excretion with office and ambulatory BP measurements. RESULTS: Mean age, ambulatory BP, sodium excretion, and estimated glomerular filtration rate in GAPP and SKIPOGH were 35 and 44 years, 123/78 and 118/77 mm Hg, 4.2 and 3.3 g/d, and 110 and 99 ml/min/1.73 m2, respectively. A weak linear association was observed between 24-hour ambulatory systolic BP and urinary sodium excretion (β (95% confidence interval [CI]) per 1 g increase in sodium excretion (0.33 % (0.09; 0.57); P = 0.008). No significant relationships were observed for 24-hour ambulatory diastolic BP (β (95% CI) (0.13 % (-0.15; 0.40) P = 0.37). When repeating the analyses in different age groups, all BP indices appeared to have stronger relationships in the older age groups (>40 years). CONCLUSIONS: In these large cohorts of healthy adults, urinary sodium excretion was only weakly associated with systolic 24-hour ambulatory BP.
BACKGROUND: While the positive relationship between urinary sodium excretion and blood pressure (BP) is well established for middle-aged to elderly individuals using office BP, data are limited for younger individuals and ambulatory BP measurements. METHODS: Our analysis included 2,899 individuals aged 18 to 90 years from 2 population-based studies (GAPP, Swiss Kidney Project on Genes in Hypertension [SKIPOGH]). Participants with prevalent cardiovascular disease, diabetes, or on BP-lowering treatment were excluded. In SKIPOGH, 24-hour urinary sodium excretion was used as a measure of sodium intake, while in GAPP it was calculated from fasting morning urinary samples using the Kawasaki formula. Multivariable linear regression models were used to assess the relationships of 24-hour urinary salt excretion with office and ambulatory BP measurements. RESULTS: Mean age, ambulatory BP, sodium excretion, and estimated glomerular filtration rate in GAPP and SKIPOGH were 35 and 44 years, 123/78 and 118/77 mm Hg, 4.2 and 3.3 g/d, and 110 and 99 ml/min/1.73 m2, respectively. A weak linear association was observed between 24-hour ambulatory systolic BP and urinary sodium excretion (β (95% confidence interval [CI]) per 1 g increase in sodium excretion (0.33 % (0.09; 0.57); P = 0.008). No significant relationships were observed for 24-hour ambulatory diastolic BP (β (95% CI) (0.13 % (-0.15; 0.40) P = 0.37). When repeating the analyses in different age groups, all BP indices appeared to have stronger relationships in the older age groups (>40 years). CONCLUSIONS: In these large cohorts of healthy adults, urinary sodium excretion was only weakly associated with systolic 24-hour ambulatory BP.