Urinary sodium excretion, blood pressure, cardiovascular disease, and mortality: a community-level prospective epidemiological cohort study

Mente A 1 , O'Donnell M 2 , Rangarajan S 3 , McQueen M 4 , Dagenais G 5 , Wielgosz A 6 Show all authors , Lear S 7 , Ah STL 8 , Wei L 9 , Diaz R 10 , Avezum A 11 , Lopez-Jaramillo P 12 , Lanas F 13 , Mony P 14 , Szuba A 15 , Iqbal R 16 , Yusuf R 17 , Mohammadifard N 18 , Khatib R 19 , Yusoff K 20 , Ismail N 21 , Gulec S 22 , Rosengren A 23 , Yusufali A 24 , Kruger L 25 , Tsolekile LP 26 , Chifamba J 27 , Dans A 28 , Alhabib KF 29 , Yeates K 30 , Teo K 31 , Yusuf S 31

Affiliations 

  • 1 Population Health Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, ON, Canada; Department of Health Research Methods, McMaster University, Hamilton, ON, Canada. Electronic address: [email protected]
  • 2 Department of Medicine, McMaster University, Hamilton, ON, Canada; HRB-Clinical Research Facility, NUI Galway, Ireland
  • 3 Population Health Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, ON, Canada
  • 4 Population Health Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, ON, Canada; Department of Laboratory Medicine, McMaster University, Hamilton, ON, Canada
  • 5 Department of Cardiology, Université Laval Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, QC, Canada
  • 6 Department of Medicine, University of Ottawa, Ottawa, ON, Canada
  • 7 Faculty of Health Sciences, Simon Fraser University, Vancouver, BC, Canada; Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Vancouver, BC, Canada
  • 8 Jockey Club School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong SAR, China
  • 9 State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
  • 10 Estudios Clinicos Latinoamerica ECLA, Rosario, Santa Fe, Argentina
  • 11 Dante Pazzanese Institute of Cardiology, Sao Paulo, Brazil
  • 12 Fundacion Oftalmologica de Santander (FOSCAL), Floridablanca-Santander, Colombia
  • 13 Universidad de La Frontera, Francisco Salazar, Temuco, Chile
  • 14 Division of Epidemiology and Population Health, St John's Medical College and Research Institute, Bangalore, India
  • 15 Department of Internal Medicine, 4th Military Hospital, Wroclaw Medical University, Wroclaw, Poland
  • 16 Department of Community Health Sciences and Medicine, Aga Khan University, Karachi, Pakistan
  • 17 Independent University, Bangladesh, Bashundhara, Dhaka, Bangladesh
  • 18 Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
  • 19 Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
  • 20 Universiti Teknologi MARA, Sungai Buloh, Selangor, Malaysia; UCSI University, Cheras, Selangor, Malaysia
  • 21 Department of Community Health, University Kebangsaan Malaysia Medical Centre, Selangor, Malaysia
  • 22 Ankara University School of Medicine, Department of Cardiology, Ankara, Turkey
  • 23 Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital/Östra Hospital, Gothenburg, Sweden
  • 24 Hatta Hospital, Dubai Health Authority, Dubai Medical University, Dubai, United Arab Emirates
  • 25 Faculty of Health Science, North-West University, Potchefstroom Campus, Potchefstroom, South Africa
  • 26 School of Public Health, University of the Western Cape, Cape Town, Western Cape Province, South Africa
  • 27 Physiology Department, University of Zimbabwe, College of Health Sciences, Harare, Zimbabwe
  • 28 University of the Philippines, Ermita, Manila, Philippines
  • 29 Department of Cardiac Sciences, King Fahad Cardiac Center, College of Medicine, King Saud University, Riyadh, Saudi Arabia
  • 30 Department of Medicine, Queen's University, Kingston, ON, Canada
  • 31 Population Health Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, ON, Canada; Department of Health Research Methods, McMaster University, Hamilton, ON, Canada; Department of Medicine, McMaster University, Hamilton, ON, Canada
Lancet, 2018 08 11;392(10146):496-506.
PMID: 30129465 DOI: 10.1016/S0140-6736(18)31376-X

Abstract

BACKGROUND: WHO recommends that populations consume less than 2 g/day sodium as a preventive measure against cardiovascular disease, but this target has not been achieved in any country. This recommendation is primarily based on individual-level data from short-term trials of blood pressure (BP) without data relating low sodium intake to reduced cardiovascular events from randomised trials or observational studies. We investigated the associations between community-level mean sodium and potassium intake, cardiovascular disease, and mortality.

METHODS: The Prospective Urban Rural Epidemiology study is ongoing in 21 countries. Here we report an analysis done in 18 countries with data on clinical outcomes. Eligible participants were adults aged 35-70 years without cardiovascular disease, sampled from the general population. We used morning fasting urine to estimate 24 h sodium and potassium excretion as a surrogate for intake. We assessed community-level associations between sodium and potassium intake and BP in 369 communities (all >50 participants) and cardiovascular disease and mortality in 255 communities (all >100 participants), and used individual-level data to adjust for known confounders.

FINDINGS: 95 767 participants in 369 communities were assessed for BP and 82 544 in 255 communities for cardiovascular outcomes with follow-up for a median of 8·1 years. 82 (80%) of 103 communities in China had a mean sodium intake greater than 5 g/day, whereas in other countries 224 (84%) of 266 communities had a mean intake of 3-5 g/day. Overall, mean systolic BP increased by 2·86 mm Hg per 1 g increase in mean sodium intake, but positive associations were only seen among the communities in the highest tertile of sodium intake (p<0·0001 for heterogeneity). The association between mean sodium intake and major cardiovascular events showed significant deviations from linearity (p=0·043) due to a significant inverse association in the lowest tertile of sodium intake (lowest tertile <4·43 g/day, mean intake 4·04 g/day, range 3·42-4·43; change -1·00 events per 1000 years, 95% CI -2·00 to -0·01, p=0·0497), no association in the middle tertile (middle tertile 4·43-5·08 g/day, mean intake 4·70 g/day, 4·44-5.05; change 0·24 events per 1000 years, -2·12 to 2·61, p=0·8391), and a positive but non-significant association in the highest tertile (highest tertile >5·08 g/day, mean intake 5·75 g/day, >5·08-7·49; change 0·37 events per 1000 years, -0·03 to 0·78, p=0·0712). A strong association was seen with stroke in China (mean sodium intake 5·58 g/day, 0·42 events per 1000 years, 95% CI 0·16 to 0·67, p=0·0020) compared with in other countries (4·49 g/day, -0·26 events, -0·46 to -0·06, p=0·0124; p<0·0001 for heterogeneity). All major cardiovascular outcomes decreased with increasing potassium intake in all countries.

INTERPRETATION: Sodium intake was associated with cardiovascular disease and strokes only in communities where mean intake was greater than 5 g/day. A strategy of sodium reduction in these communities and countries but not in others might be appropriate.

FUNDING: Population Health Research Institute, Canadian Institutes of Health Research, Canadian Institutes of Health Canada Strategy for Patient-Oriented Research, Ontario Ministry of Health and Long-Term Care, Heart and Stroke Foundation of Ontario, and European Research Council.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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