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BMJ. Apr 6, 1991; 302(6780): 815–818.
PMCID: PMC1669173

By how much does dietary salt reduction lower blood pressure? II--Analysis of observational data within populations.

Abstract

OBJECTIVE--To determine whether the estimates of the size of the association between blood pressure and sodium intake derived from studies of individuals within populations can be quantitatively reconciled with our estimates derived from comparisons of the average blood pressure and sodium intake between different populations. DESIGN--Examination of data from 14 published studies that correlated blood pressure recordings in individuals against measurements of their 24 hour sodium intake (within population studies). MAIN OUTCOME MEASURE--Comparison of observed differences in blood pressure per 100 mmol/24 h difference in sodium intake in each within population study with predicted differences calculated from the between population data, after allowing for the underestimation of the true association of blood pressure with sodium intake caused by the large day to day variation in 24 hour sodium intake within individuals. RESULTS--The underestimation bias inherent in the within populations studies reduced the regression slope of blood pressure on single measures of 24 hour sodium intake to between a half and a quarter of the true value (for example, in one study from 6.0 to 2.4 mm Hg/100 mmol/24 h). Estimates from between population comparisons of the regression slope of blood pressure on sodium intake, after adjustment to take this underestimation bias into account, were similar to the values actually observed in the within population studies. CONCLUSION--The within population studies confirm our estimates from between population comparisons of the magnitude of the association between blood pressure and sodium intake.

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Selected References

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  • Law MR, Frost CD, Wald NJ. By how much does dietary salt reduction lower blood pressure? I--Analysis of observational data among populations. BMJ. 1991 Apr 6;302(6780):811–815. [PMC free article] [PubMed]
  • Liu K, Cooper R, McKeever J, McKeever P, Byington R, Soltero I, Stamler R, Gosch F, Stevens E, Stamler J. Assessment of the association between habitual salt intake and high blood pressure: methodological problems. Am J Epidemiol. 1979 Aug;110(2):219–226. [PubMed]
  • Luft FC, Aronoff GR, Sloan RS, Fineberg NS. Intra- and interindividual variability in sodium intake in normal subjects and in patients with renal insufficiency. Am J Kidney Dis. 1986 May;7(5):375–380. [PubMed]
  • Law MR, Frost CD, Wald NJ. By how much does dietary salt reduction lower blood pressure? III--Analysis of data from trials of salt reduction. BMJ. 1991 Apr 6;302(6780):819–824. [PMC free article] [PubMed]
  • Liu LS, Zheng DY, Jin L, Liao YL, Liu K, Stamler J. Variability of urinary sodium and potassium excretion in north Chinese men. J Hypertens. 1987 Jun;5(3):331–335. [PubMed]
  • Siani A, Iacoviello L, Giorgione N, Iacone R, Strazzullo P. Comparison of variability of urinary sodium, potassium, and calcium in free-living men. Hypertension. 1989 Jan;13(1):38–42. [PubMed]
  • Elliott P, Forrest RD, Jackson CA, Yudkin JS. Sodium and blood pressure: positive associations in a north London population with consideration of the methodological problems of within-population surveys. J Hum Hypertens. 1988 Aug;2(2):89–95. [PubMed]
  • Connor SL, Connor WE, Henry H, Sexton G, Keenan EJ. The effects of familial relationships, age, body weight, and diet on blood pressure and the 24 hour urinary excretion of sodium, potassium, and creatinine in men, women, and children of randomly selected families. Circulation. 1984 Jul;70(1):76–85. [PubMed]
  • Staessen J, Bulpitt C, Fagard R, Joossens JV, Lijnen P, Amery A. Four urinary cations and blood pressure. A population study in two Belgian towns. Am J Epidemiol. 1983 Jun;117(6):676–687. [PubMed]
  • Kesteloot H, Huang DX, Li YL, Geboers J, Joossens JV. The relationship between cations and blood pressure in the People's Republic of China. Hypertension. 1987 Jun;9(6):654–659. [PubMed]
  • Strazzullo P, Trevisan M, Farinaro E, Cappuccio FP, Ferrara LA, de Campora E, Mancini M. Characteristics of the association between salt intake and blood pressure in a sample of male working population in southern Italy. Eur Heart J. 1983 Sep;4(9):608–613. [PubMed]
  • Smith WC, Crombie IK, Tavendale RT, Gulland SK, Tunstall-Pedoe HD. Urinary electrolyte excretion, alcohol consumption, and blood pressure in the Scottish heart health study. BMJ. 1988 Jul 30;297(6644):329–330. [PMC free article] [PubMed]
  • Bulpitt CJ, Broughton PM, Markowe HL, Marmot MG, Rose G, Semmence A, Shipley MJ. The relationship between both sodium and potassium intake and blood pressure in London Civil Servants. A report from the Whitehall Department of Environment Study. J Chronic Dis. 1986;39(3):211–219. [PubMed]
  • Kesteloot H, Park BC, Lee CS, Brems-Heyns E, Claessens J, Joossens JV. A comparative study of blood pressure and sodium intake in Belgium and in Korea. Eur J Cardiol. 1980 Mar;11(3):169–182. [PubMed]
  • Watt GC, Foy CJ. Dietary sodium and arterial pressure: problems of studies within a single population. J Epidemiol Community Health. 1982 Sep;36(3):197–201. [PMC free article] [PubMed]

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