151
|
Charlton KE, Steyn K, Levitt NS, Zulu JV, Jonathan D, Veldman FJ, Nel JH. Diet and blood pressure in South Africa: Intake of foods containing sodium, potassium, calcium, and magnesium in three ethnic groups. Nutrition 2005; 21:39-50. [PMID: 15661477 DOI: 10.1016/j.nut.2004.09.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2004] [Accepted: 07/02/2004] [Indexed: 10/25/2022]
Abstract
OBJECTIVES We investigated whether habitual intakes of sodium (Na), potassium, magnesium, and calcium differ across South African ethnic groups, assessed the proportion of Na intake, which is discretionary, and identified which food sources were the major contributors to Na intake. METHODS This was a cross-sectional study of 325 black, white, and mixed ancestry hypertensive and normotensive subjects. Three repeated 24-h urine samples were collected for assessment of urinary Na, and three corresponding 24-h dietary recalls were administered by trained fieldworkers. Blood pressure and weight were measured at each visit. Secondary analyses were performed on existing dietary databases obtained from four regional surveys undertaken in South African adults. RESULTS Mean urinary Na excretion values equated to daily salt (NaCl) intakes of 7.8, 8.5, and 9.5 g in black, mixed ancestry, and white subjects, respectively (P < 0.05). Between 33% and 46% of total Na intake was discretionary, and, of the non-discretionary sources, bread was the single greatest contributor to Na intake in all groups. Ethnic differences in calcium intake were evident, with black subjects having particularly low intakes. Urban versus rural differences existed with respect to sources of dietary Na, with greater than 70% of total non-discretionary Na being provided by bread and cereals in rural black South Africans compared with 49% to 54% in urban dwellers. CONCLUSION White South Africans have higher habitual intakes of Na, but also higher calcium intakes, than their black and mixed ancestry counterparts. All ethnic groups had Na intakes in excess of 6 g/d of salt, whereas potassium intakes in all groups were below the recommended level of 90 mM/d. Dietary differences may contribute to ethnically related differences in blood pressure.
Collapse
Affiliation(s)
- Karen E Charlton
- Chronic Diseases of Lifestyle Unit, Medical Research Council, Tygerberg, South Africa.
| | | | | | | | | | | | | |
Collapse
|
152
|
Abstract
PURPOSE OF REVIEW While treating high blood pressure in middle age is beneficial in terms of reducing the occurrence of cardiovascular disease, treated and well controlled hypertensive adults still have a substantial excess mortality and reduced survival compared with normotensives. Therefore, identification of the means of preventing hypertension in earlier life is an important objective. There is increasing evidence that adult blood pressure is determined by a range of characteristics from the intrauterine period, through infancy and childhood. The purpose of this review is to provide a summary of the current evidence concerning the early life determinants of adult blood pressure. RECENT FINDINGS Children from poorer socioeconomic positions, those whose mothers experience pregnancy-induced hypertension, those whose mothers smoke throughout pregnancy, those with low birthweight, who are not breast-fed, who have high sodium diets in infancy and who are obese in childhood or adolescence tend to have higher blood pressure in adulthood. However, the mechanisms linking these early life factors to later blood pressure and the most appropriate means of preventing adult hypertension by intervening in early life are unclear. SUMMARY There is clear evidence that early life factors are important determinants of adult blood pressure. However, there is a need for randomized trials with sufficient resources for long-term follow-up to assess the effects that interventions such as preventing pregnancy-induced hypertension, reducing maternal smoking, increasing breast-feeding, reducing salt consumption in infancy and preventing childhood obesity have on adult blood pressure and cardiovascular disease.
Collapse
Affiliation(s)
- Debbie A Lawlor
- Department of Social Medicine, University of Bristol, Bristol, UK
| | | |
Collapse
|
153
|
Lipowicz A, Lopuszanska M. Marital differences in blood pressure and the risk of hypertension among Polish men. Eur J Epidemiol 2005; 20:421-7. [PMID: 16080590 DOI: 10.1007/s10654-005-1752-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The aim of the study was to evaluate the relationship between marital status and blood pressure, and to assess the risk of hypertension in adult Polish men, after adjustment for BMI. Material comprised the data of 2,271 healthy men, aged 25-60, occupationally active inhabitants of Wroclaw (south-western Poland). Arterial hypertension was diagnosed when systolic blood pressure (SBP) > or =140 mm Hg and/or diastolic blood pressure (DBP) > or = 90 mm Hg. The following categories of marital status and educational level were applied: never married vs. currently married, and well-educated vs. poorly educated, respectively. The data on lifestyle elements were obtained from questionnaires. Multi-factorial analyses of covariance (ANCOVA) were used to compare mean values of SBP and DBP in married vs. never married in subsequent age categories with BMI as a covariate. Independent effects of marital status, life-style variables and body mass index (BMI) on the risk of hypertension in men were analysed using the multifactorial models of logistic regression. In our analysis an interesting epidemiological phenomenon was observed. Never married men had on average higher SBP and DBP than married men. Never married had also a higher risk of hypertension when compared to married men, even when adjusted for different demographic, socio-economic, life-style variables, and even that never married men had lower BMI than married subjects. Marital differences in psychological status (prolonged stress and low social support), dietary intake (mainly sodium and potassium intake) and economic aspects of living alone are suggested as factors, which might explain at least partly the marital diversity in blood pressure and the risk of hypertension in men.
Collapse
Affiliation(s)
- Anna Lipowicz
- Institute of Anthropology, Polish Academy of Sciences, Wrocław, Poland.
| | | |
Collapse
|
154
|
Schneider RH, Alexander CN, Staggers F, Orme-Johnson DW, Rainforth M, Salerno JW, Sheppard W, Castillo-Richmond A, Barnes VA, Nidich SI. A randomized controlled trial of stress reduction in African Americans treated for hypertension for over one year. Am J Hypertens 2005; 18:88-98. [PMID: 15691622 PMCID: PMC2224896 DOI: 10.1016/j.amjhyper.2004.08.027] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Revised: 08/14/2004] [Accepted: 08/27/2004] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Psychosocial stress has been implicated in the disproportionately higher rates of hypertension among African Americans. This randomized controlled trial compared the effects of two stress reduction techniques and a health education control program on hypertension during a period of 1 year in African-American men and women (N = 150, mean age 49 +/- 10 years, mean blood pressure (BP) = 142/95 mm Hg) at an urban community health center. METHODS Interventions included 20 min twice a day of Transcendental Meditation (TM) or progressive muscle relaxation (PMR), or participation in conventional health education (HE) classes. All subjects continued usual medical care. Outcomes assessed were systolic BP and diastolic BP at 3, 6, 9, and 12 months after treatment, analyzed by repeated measures ANCOVA. RESULTS The TM group showed decreases in systolic BP/diastolic BP of -3.1/-5.7 mm Hg compared to -0.5/-2.9 mm Hg for PMR or HE, (P = .12 to .17 for systolic BP, P = .01 for diastolic BP). In addition the TM group demonstrated reduced use of antihypertensive medication relative to increases for PMR (P = .001) and HE (P = .09) groups. Group analysis by gender showed that women practicing TM had decreased BP (-7.3/-6.9 mm Hg) significantly more than women practicing PMR (0.7/-2.7 mm Hg) or HE (-.07/-3.0 mm Hg) (P .01 to .03). The change in men praticing TM (0.2 /-4.7 mm Hg) was greater than men practicing HE (-0.9/-2.0 mm Hg) for diastolic BP only (P = .09,) and not different from PMR men (-2.0/-3.1). CONCLUSIONS A selected stress reduction approach, the Transcendental Meditation program, may be useful as an adjunct in the long-term treatment of hypertension in African Americans.
Collapse
Affiliation(s)
- Robert H Schneider
- Institute for Natural Medicine and Prevention, Maharishi University of Management, Fairfield, Iowa, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
155
|
McCarron DA, Reusser ME. Diet: Micronutrients. Hypertension 2005. [DOI: 10.1016/b978-0-7216-0258-5.50132-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
156
|
|
157
|
Khaw KT, Bingham S, Welch A, Luben R, O'Brien E, Wareham N, Day N. Blood pressure and urinary sodium in men and women: the Norfolk Cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk). Am J Clin Nutr 2004; 80:1397-403. [PMID: 15531692 DOI: 10.1093/ajcn/80.5.1397] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Abundant evidence indicates that a high sodium intake is causally related to high blood pressure, but debate over recommendations to reduce dietary sodium in the general population continues. A key issue is whether differences in usual sodium intake within the range feasible in free-living populations have clinical or public health relevance. OBJECTIVE We examined the relation between blood pressure and urinary sodium as a marker of dietary intake. DESIGN This was a study of 23104 community-living adults aged 45-79 y. RESULTS Mean systolic and diastolic blood pressure increased as the ratio of urinary sodium to creatinine increased (as estimated from a casual urine sample), with differences of 7.2 mm Hg for systolic blood pressure and 3.0 mm Hg for diastolic blood pressure (P < 0.0001) between the top and bottom quintiles. This trend was independent of age, body mass index, urinary potassium:creatinine, and smoking and was consistent by sex and history of hypertension. The prevalence of those with systolic blood pressure >/= 160 mm Hg halved from 12% in the top quintile to 6% in the bottom quintile; the odds ratio for having systolic blood pressure >/= 160 mm Hg was 2.48 (95% CI: 1.90, 3.22) for men and 2.67 (95% CI: 2.08, 3.43) for women in the top compared with the bottom quintile of urinary sodium. Estimated mean sodium intakes in the lowest and highest quintiles were approximately 80 and 220 mmol/d, respectively. CONCLUSIONS Within the usual range found in a free-living population, differences in urinary sodium, an indicator of dietary sodium intake, are associated with blood pressure differences of clinical and public health relevance. Our findings reinforce recommendations to lower average sodium intakes in the general population.
Collapse
Affiliation(s)
- Kay-Tee Khaw
- Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
158
|
Kumanyika SK, Cook NR, Cutler JA, Belden L, Brewer A, Cohen JD, Hebert PR, Lasser VI, Raines J, Raczynski J, Shepek L, Diller L, Whelton PK, Yamamoto M. Sodium reduction for hypertension prevention in overweight adults: further results from the Trials of Hypertension Prevention Phase II. J Hum Hypertens 2004; 19:33-45. [PMID: 15372064 DOI: 10.1038/sj.jhh.1001774] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sodium reduction is efficacious for primary prevention of hypertension, but the feasibility of achieving this effect is unclear. The objective of the paper is detailed analyses of adherence to and effects of the sodium reduction intervention among overweight adults in the Trials of Hypertension Prevention, Phase II. Sodium reduction (comprehensive education and counselling about how to reduce sodium intake) was tested vs no dietary intervention (usual care) for 36-48 months. A total of 956 white and 203 black adults, ages 30-54 years, with diastolic blood pressure 83-89 mmHg, systolic blood pressure (SBP) <140 mmHg, and body weight 110-165% of gender-specific standard weight were included in the study. At 36 months, urinary sodium excretion was 40.4 mmol/24 h (24.4%) lower in sodium reduction compared to usual care participants (P<0.0001), but only 21% of sodium reduction participants achieved the targeted level of sodium excretion below 80 mmol/24 h. Adherence was positively related to attendance at face-to-face contacts. Net decreases in SBP at 6, 18, and 36 months of 2.9 (P<0.001), 2.0 (P<0.001), and 1.3 (P=0.02) mmHg in sodium reduction vs usual care were associated with an overall 18% lower incidence of hypertension (P=0.048); were relatively unchanged by adjustment for ethnicity, gender, age, and baseline blood pressure, BMI, and sodium excretion; and were observed in both black and white men and women. From these beneficial but modest results with highly motivated and extensively counselled individuals, sodium reduction sufficient to favourably influence the population blood pressure distribution will be difficult to achieve without food supply changes.
Collapse
Affiliation(s)
- S K Kumanyika
- University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
159
|
Cook NR, Kumanyika SK, Cutler JA, Whelton PK. Dose–response of sodium excretion and blood pressure change among overweight, nonhypertensive adults in a 3-year dietary intervention study. J Hum Hypertens 2004; 19:47-54. [PMID: 15343354 DOI: 10.1038/sj.jhh.1001775] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A cross-sectional dose-response relationship between sodium intake and blood pressure (BP) has been demonstrated, but evidence for a graded longitudinal effect is limited. Evaluation of BP response to sodium reduction was assessed in a 3-year lifestyle dietary intervention trial. BP changes at 18 and 36 months after enrollment were analysed according to concurrent quantitative changes in sodium excretion and by categories of success in sodium reduction among 1157 men and women, ages 30-54 years, with a diastolic BP (DBP) 83-89 mmHg, systolic BP (SBP) <140 mmHg, body weight 110-165% of sex-specific standard weight, and valid baseline urinary sodium excretion. Participants were randomized to a Sodium Reduction intervention (n=581) or Usual Care (n=576). From a 187 mmol/24 h baseline mean sodium excretion, net decreases were 44 mmol/24 h at 18 months and 38 mmol/24 h at 36 months in Sodium Reduction vs Usual Care. Corresponding net decreases in SBP/DBP were 2.0/1.4 mmHg at 18 months, and 1.7/0.9 mmHg at 36 months. Significant dose-response trends in BP change over quintiles of achieved sodium excretion were seen at both 18 (SBP and DBP) and 36 (SBP only) months; effects appeared stronger among those maintaining sodium reduction. Estimated SBP decreases per 100 mmol/24 h reduction in sodium excretion at 18 and 36 months were 2.2 and 1.3 mmHg before and 7.0 and 3.6 mmHg after correction for measurement error, respectively. DBP changes were smaller and nonsignificant at 36 months. In conclusion, incremental decreases in BP with lower sodium excretion were observed in these overweight nonhypertensive individuals.
Collapse
Affiliation(s)
- N R Cook
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215-1204, USA.
| | | | | | | |
Collapse
|
160
|
|
161
|
Li D, Xing H, Hao K, Peng S, Wu D, Guang W, Huang A, Wang Y, Zhang Y, Yu Y, Li J, Chen C, Wang B, Zhu G, Huo Y, Chen D, Ronnenberg A, Niu T, Xu X. Hypertensive patients from two rural Chinese counties respond differently to benazepril: the Anhui Hypertension Health Care Study. Ann Epidemiol 2004; 14:123-8. [PMID: 15018885 DOI: 10.1016/s1047-2797(03)00118-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2002] [Accepted: 05/08/2003] [Indexed: 11/30/2022]
Abstract
PURPOSE Essential hypertension, as a complex disorder with unknown etiology cause, is a major public health problem worldwide. Patients need constant drug therapy to maintain their blood pressure in a normal range. However, the current facts suggest that the treatment is not optimized in a large number of patients, and as a result they are at risk for compliance resulting in uncontrolled blood pressure. Genetic and environmental factors associated with individual variation in response to anti-hypertensive drug remain largely unknown. METHODS In order to illustrate the existence and to attempt to identify the factors modifying drug effect, we conducted a large-scale follow-up study in two Chinese rural counties differing in both genetic background and residential environment. Hypertensive patients were treated with benazepril, a commonly used angiotensin converting enzyme inhibitor, for 15 days, and the end-point effect was evaluated. RESULTS We found that there were large and significant differences in drug response between subjects from two counties, even after adjustment for known factors. The responses to benazepril, measured in diastolic blood pressure drop, in male patients from Yuexi was twice as effective as their counterparts from Huoqiu. CONCLUSIONS These results suggest that adjustment of treatment regimen is necessary to improve efficacy, and it could be done at the population level to make it more feasible and affordable.
Collapse
Affiliation(s)
- Dong Li
- School of Life Science, University of Science and Technology in China, Hefei, China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
162
|
Abstract
Most patients with chronic kidney disease (CKD) also have hypertension. It is critical to control blood pressure in CKD to decrease the risk of negative outcomes. Modification of diet can reduce blood pressure, most notably in people with hypertension and in older adults. Current guidelines recommend reducing sodium intake to less than 2.4 g/day and increasing potassium and calcium intakes. Sodium reduction is supported for CKD patients in general. However, increasing potassium intake should be restricted in patients with glomerular filtration rate (GFR) less than 60 mL/min/1.73 m(2). In addition, because of the high phosphorus levels of many calcium-rich foods such as dairy products, calcium intake also should be limited in this low-GFR population. There is increasing evidence for the association of other nutrients such as omega-3 polyunsaturated fatty acids and vitamin C with blood pressure. Those nutrients are also discussed here.
Collapse
Affiliation(s)
- Kristie J Lancaster
- Department of Nutrition, Food Studies, and Public Health, New York University, 35 W 4th Street, 10th Floor, New York, NY 10012 USA.
| |
Collapse
|
163
|
Williams B, Poulter NR, Brown MJ, Davis M, McInnes GT, Potter JF, Sever PS, McG Thom S. Guidelines for management of hypertension: report of the fourth working party of the British Hypertension Society, 2004—BHS IV. J Hum Hypertens 2004; 18:139-85. [PMID: 14973512 DOI: 10.1038/sj.jhh.1001683] [Citation(s) in RCA: 685] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- B Williams
- Department of Cardiovascular Sciences, Clinical Sciences Building, Leicester Royal Infirmary, University of Leicester, UK.
| | | | | | | | | | | | | | | |
Collapse
|
164
|
Fairweather-Tait SJ. Human nutrition and food research: opportunities and challenges in the post-genomic era. Philos Trans R Soc Lond B Biol Sci 2004; 358:1709-27. [PMID: 14561328 PMCID: PMC1693270 DOI: 10.1098/rstb.2003.1377] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Sequencing of the human genome has opened the door to the most exciting new era for nutritional science. It is now possible to study the underlying mechanisms for diet-health relationships, and in the near future dietary advice (and possibly tailored food products) for promoting optimal health could be provided on an individual basis, in relation to genotype and lifestyle. The role of food in human evolution is briefly reviewed, from palaeolithic times to modern-day hunter-gatherer societies. The aetiology of 'diseases of modern civilization', such as diabetes, heart disease and cancer, and the effect of changes in dietary patterns are discussed. The risk of disease is often associated with common single nucleotide polymorphisms, but the effect is dependent on dietary intake and nutritional status, and is often more apparent in intervention studies employing a metabolic challenge. To understand the link between diet and health, nutritional research must cover a broad range of areas, from molecular to whole body studies, and is an excellent example of integrative biology, requiring a systems biology approach. The annual cost to the National Health Service of diet-related diseases is estimated to be in excess of 15 billion, and although diet is a key component of any preventative strategy, it is not given the prominence it deserves. For example, less than 1% of the pound 1.6 billion budget for coronary heart disease is spent on prevention. The polygenic and multifactorial nature of chronic diseases requires substantial resources but the potential rewards, in terms of quality of life and economics, are enormous. It is timely therefore to consider investing in a long-term coordinated national programme for nutrition research, combining nutritional genomics with established approaches, to improve the health of individuals and of the nation.
Collapse
|
165
|
Hooper L, Bartlett C, Davey SG, Ebrahim S. Advice to reduce dietary salt for prevention of cardiovascular disease. Cochrane Database Syst Rev 2004:CD003656. [PMID: 14974027 DOI: 10.1002/14651858.cd003656.pub2] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Restricting sodium intake in elevated blood pressure over short periods of time reduces blood pressure. Long term effects (on mortality, morbidity or blood pressure) of advice to reduce salt in patients with elevated or normal blood pressure are unclear. OBJECTIVES To assess in adults the long term effects (mortality, cardiovascular events, blood pressure, quality of life, weight, urinary sodium excretion, other nutrients and use of anti-hypertensive medications) of advice to restrict dietary sodium using all relevant randomised controlled trials. SEARCH STRATEGY The Cochrane Library, MEDLINE, EMBASE, bibliographies of included studies and related systematic reviews were searched for unconfounded randomised trials in healthy adults aiming to reduce sodium intake over at least 6 months. Attempts were made to trace unpublished or missed studies and authors of all included trials were contacted. There were no language restrictions. SELECTION CRITERIA Inclusion decisions were independently duplicated and based on the following criteria: 1) randomisation was adequate; 2) there was a usual or control diet group; 3) the intervention aimed to reduce sodium intake; 4) the intervention was not multifactorial; 5) the participants were not children, acutely ill, pregnant or institutionalised; 6) follow-up was at least 26 weeks; 7) data on any of the outcomes of interest were available. DATA COLLECTION AND ANALYSIS Decisions on validity and data extraction were made independently by two reviewers, disagreements were resolved by discussion or if necessary by a third reviewer. Random effects meta-analysis, sub-grouping, sensitivity analysis and meta-regression were performed. MAIN RESULTS Three trials in normotensives (n=2326), five in untreated hypertensives (n=387) and three in treated hypertensives (n=801) were included, with follow up from six months to seven years. The large, high quality (and therefore most informative) studies used intensive behavioural interventions. Deaths and cardiovascular events were inconsistently defined and reported; only 17 deaths equally distributed between intervention and control groups occurred. Systolic and diastolic blood pressures were reduced at 13 to 60 months in those given low sodium advice as compared with controls (systolic by 1.1 mm Hg, 95% CI 1.8 to 0.4, diastolic by 0.6 mm hg, 95% CI 1.5 to -0.3), as was urinary 24 hour sodium excretion (by 35.5 mmol/ 24 hours, 95% CI 47.2 to 23.9). Degree of reduction in sodium intake and change in blood pressure were not related. People on anti-hypertensive medications were able to stop their medication more often on a reduced sodium diet as compared with controls, while maintaining similar blood pressure control. REVIEWER'S CONCLUSIONS Intensive interventions, unsuited to primary care or population prevention programmes, provide only minimal reductions in blood pressure during long-term trials. Further evaluations to assess effects on morbidity and mortality outcomes are needed for populations as a whole and for patients with elevated blood pressure. Evidence from a large and small trial showed that a low sodium diet helps in maintenance of lower blood pressure following withdrawal of antihypertensives. If this is confirmed, with no increase in cardiovascular events, then targeting of comprehensive dietary and behavioural programmes in patients with elevated blood pressure requiring drug treatment would be justified.
Collapse
Affiliation(s)
- L Hooper
- MANDEC, University Dental Hospital of Manchester, Higher Cambridge Street, Manchester, UK, M15 6FH
| | | | | | | |
Collapse
|
166
|
Jürgens G, Graudal NA. Effects of low sodium diet versus high sodium diet on blood pressure, renin, aldosterone, catecholamines, cholesterols, and triglyceride. Cochrane Database Syst Rev 2004:CD004022. [PMID: 14974053 DOI: 10.1002/14651858.cd004022.pub2] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND One of the controversies in preventive medicine is, whether a general reduction in sodium intake can decrease the blood pressure of a population and thereby reduce cardiovascular mortality and morbidity. In recent years the debate has been extended by studies indicating that reducing sodium intake has effects on the hormone and lipid profile. OBJECTIVES To estimate the effects of low sodium versus high sodium intake on systolic and diastolic blood pressure (SBP and DBP), plasma or serum levels of renin, aldosterone, catecholamines, cholesterol and triglycerides. SEARCH STRATEGY "MEDLINE" and reference lists of relevant articles were searched from 1966 through December 2001. SELECTION CRITERIA Studies randomising persons to low sodium and high sodium diets were included if they evaluated at least one of the above outcome parameters. DATA COLLECTION AND ANALYSIS Two authors independently extracted the data, which were analysed by means of Review Manager 4.1. MAIN RESULTS In 57 trials of mainly Caucasians with normal blood pressure, low sodium intake reduced SBP by -1.27 mm Hg (CI: -1.76; -0.77)(p<0.0001) and DBP by -0.54 mm Hg (CI: -0.94; -0.14) (p = 0.009) as compared to high sodium intake. In 58 trials of mainly Caucasians with elevated blood pressure, low sodium intake reduced SBP by -4.18 mm Hg (CI: -5.08; - 3.27) (p < 0.0001) and DBP by -1.98 mm Hg (CI: -2.46; -1.32) (p < 0.0001) as compared to high sodium intake. The median duration of the intervention was 8 days in the normal blood pressure trials (range 4-1100) and 28 days in the elevated blood pressure trials (range 4-365). Multiple regression analyses showed no independent effect of duration on the effect size. In 8 trials of blacks with normal or elevated blood pressure, low sodium intake reduced SBP by -6.44 mm Hg (CI: -9.13; -3.74) (p < 0.0001) and DBP by -1.98 mm Hg (CI: -4.75; 0.78) (p = 0.16) as compared to high sodium intake. The magnitude of blood pressure reduction was also greater in a single trial in Japanese patients. There was also a significant increase in plasma or serum renin, 304% (p < 0.0001), aldosterone, 322%, (p < 0.0001), noradrenaline, 30% (p < 0.0001), cholesterol, 5.4% (p < 0.0001) and LDL cholesterol, 4.6% (p < 0.004), and a borderline increase in adrenaline, 12% (p = 0.04) and triglyceride, 5.9% (p = 0.03) with low sodium intake as compared with high sodium intake. REVIEWER'S CONCLUSIONS The magnitude of the effect in Caucasians with normal blood pressure does not warrant a general recommendation to reduce sodium intake. Reduced sodium intake in Caucasians with elevated blood pressure has a useful effect to reduce blood pressure in the short-term. The results suggest that the effect of low versus high sodium intake on blood pressure was greater in Black and Asian patients than in Caucasians. However, the number of studies in black (8) and Asian patients (1) was insufficient for different recommendations. Additional long-term trials of the effect of reduced dietary sodium intake on blood pressure, metabolic variables, morbidity and mortality are required to establish whether this is a useful prophylactic or treatment strategy.
Collapse
|
167
|
Suárez Fernández C. ¿Es realmente útil la restricción salina en el tratamiento de la hipertensión arterial? HIPERTENSION Y RIESGO VASCULAR 2004. [DOI: 10.1016/s1889-1837(04)71498-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
168
|
Abstract
BACKGROUND Many randomised trials assessing the effect of salt reduction on blood pressure show reduction in blood pressure in individuals with high blood pressure. However, there is controversy about the magnitude and the clinical significance of the fall in blood pressure in individuals with normal blood pressure. Several meta-analyses of randomised salt reduction trials have been published in the last few years. However, most of these included trials of very short duration (e.g. 5 days) and included trials with salt loading followed by salt deprivation (e.g. from 20 to 1 g/day) over only a few days. These short-term experiments are not appropriate to inform public health policy which is for a modest reduction in salt intake over a prolonged period of time. A meta-analysis by Hooper et al is an important attempt to look at whether advice to achieve a long-term salt reduction (i.e. more than 6 months) in randomised trials causes a fall in blood pressure. However, most trials included in this meta-analysis achieved a small reduction in salt intake; on average, salt intake was reduced by 2 g/day. It is, therefore, not surprising that this analysis showed a small fall in blood pressure, and that a dose-response to salt reduction was not demonstrable. OBJECTIVES To assess the effect of the currently recommended modest reduction in salt intake (WHO 2003; SACN 2003; Whelton 2002), on blood pressure in individuals with normal and elevated blood pressure. To assess whether the magnitude of the reduction in blood pressure is dependent on the magnitude of the reduction in salt intake. SEARCH STRATEGY We searched MEDLINE, EMBASE, Cochrane library, CINAHL, and reference list of original and review articles. SELECTION CRITERIA We included randomised trials with a modest reduction in salt intake and a duration of 4 or more weeks. DATA COLLECTION AND ANALYSIS Data were extracted independently by two persons. Mean effect sizes were calculated using both fixed and random effect models using Review Manager 4.2.1 software. Weighted linear regression was used to examine the relationship between the change in urinary sodium and the change in blood pressure. We used funnel plots to detect publication and other biases in the meta-analysis. MAIN RESULTS Seventeen trials in individuals with elevated blood pressure (n=734) and 11 trials in individuals with normal blood pressure (n=2220) were included. In individuals with elevated blood pressure the median reduction in 24-h urinary sodium excretion was 78 mmol (4.6 g/day of salt), the mean reduction in systolic blood pressure was -4.97 mmHg (95%CI:-5.76 to -4.18), and the mean reduction in diastolic blood pressure was -2.74 mmHg (95% CI:-3.22 to -2.26). In individuals with normal blood pressure the median reduction in 24-h urinary sodium excretion was 74 mmol (4.4 g/day of salt), the mean reduction in systolic blood pressure was -2.03 mmHg (95% CI: -2.56 to -1.50) mmHg, and the mean reduction in diastolic blood pressure was -0.99 mmHg (-1.40 to -0.57). Weighted linear regression analyses showed a correlation between the reduction in urinary sodium and the reduction in blood pressure. REVIEWERS' CONCLUSIONS Our meta-analysis demonstrates that a modest reduction in salt intake for a duration of 4 or more weeks has a significant and, from a population viewpoint, important effect on blood pressure in both individuals with normal and elevated blood pressure. These results support other evidence suggesting that a modest and long-term reduction in population salt intake could reduce strokes, heart attacks, and heart failure. Furthermore, our meta-analysis demonstrates a correlation between the magnitude of salt reduction and the magnitude of blood pressure reduction. Within the daily intake range of 3 to 12 g/day, the lower the salt intake achieved, the lower the blood pressure.
Collapse
|
169
|
De Backer G, Ambrosioni E, Broch-Johnsen K, Brotons C, Cifkova R, Dallongeville J, Ebrahim S, Faergeman O, Graham I, Mancia G, Cats VM, Orth-Gom??r K, Perk J, Py??r??l?? K, Rodicio JL, Sans S, Sansoy V, Sechtem U, Silber S, Thomsen T, Wood D. European guidelines on cardiovascular disease prevention in clinical practice Third Joint Task Force of European and other Societies on Cardiovascular Disease Prevention in Clinical Practice (constituted by representatives of eight societies and by invited experts). ACTA ACUST UNITED AC 2003. [DOI: 10.1097/00149831-200312001-00001] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
170
|
Abstract
The current public health recommendations are to reduce salt intake from 9 to 12 g/d to 5 to 6 g/d. However, these values are based on what is feasible rather than the maximum effect of salt reduction. In a meta-analysis of longer-term trials, we looked at the dose response between salt reduction and fall in blood pressure and compared this with 2 well-controlled studies of 3 different salt intakes. All 3 studies demonstrated a consistent dose response to salt reduction within the range of 12 to 3 g/d. A reduction of 3 g/d predicts a fall in blood pressure of 3.6 to 5.6/1.9 to 3.2 mm Hg (systolic/diastolic) in hypertensives and 1.8 to 3.5/0.8 to 1.8 mm Hg in normotensives. The effect would be doubled with a 6 g/d reduction and tripled with a 9 g/d reduction. A conservative estimate indicates that a reduction of 3 g/d would reduce strokes by 13% and ischemic heart disease (IHD) by 10%. The effects would be almost doubled with a 6 g/d reduction and tripled with a 9 g/d reduction. Reducing salt intake by 9 g/d (eg, from 12 to 3 g/d) would reduce strokes by approximately one third and IHD by one quarter, and this would prevent approximately 20 500 stroke deaths and 31 400 IHD deaths a year in the United Kingdom. The current recommendations to reduce salt intake from 9 to 12 g/d to 5 to 6 g/d will have a major effect on blood pressure and cardiovascular disease but are not ideal. A further reduction to 3 g/d will have a much greater effect and should now become the long-term target for population salt intake worldwide.
Collapse
Affiliation(s)
- Feng J He
- Blood Pressure Unit, St George's Hospital Medical School, Cranmer Terrace, London, England
| | | |
Collapse
|
171
|
Micheli ET, Rosa AA. Estimation of sodium intake by urinary excretion and dietary records in children and adolescents from Porto Alegre, Brazil: a comparision of two methods. Nutr Res 2003. [DOI: 10.1016/s0271-5317(03)00157-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
172
|
A Comparison of Outcomes with Angiotensin-converting Enzyme. Curr Hypertens Rep 2003. [DOI: 10.1007/s11906-003-0079-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
173
|
Kaplan NM, Vidt DG. A comparison of outcomes with angiotensin-converting enzyme inhibitors and diuretics for hypertension in the elderly. Curr Hypertens Rep 2003; 5:362-3. [PMID: 12948426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Affiliation(s)
- Norman M Kaplan
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75235, USA.
| | | |
Collapse
|
174
|
Bauhofer A, Tischer B, Middeke M, Plaul U, Lorenz W, Torossian A. The Genetic Background of Hypertensive, Septic Rats Determines Outcome Improvement With Antibiotic and G-CSF Prophylaxis. Shock 2003; 20:326-31. [PMID: 14501946 DOI: 10.1097/01.shk.0000084342.58020.1e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Hypertension is proposed as a risk factor among others (high age, diabetes mellitus, and pre- and intraoperative bleeding) for adverse outcomes, such as severe infections, leading to sepsis and to multiple organ failure as the most deleterious complication. Hypertension was modeled with spontaneous hypertensive rats (SHR) and Dahl salt-sensitive (DS) rats and the infective complication by polymicrobial, peritoneal contamination, and infection (PCI). The concept of clinic modeling randomized trials was used to simulate clinical complexity, including a relevant antibiotic prophylaxis in combination with granulocyte-colony stimulating factor (G-CSF) and clinical trial conditions. Outcome parameters were: survival, systemic cytokines (protein), and organ-specific cytokine levels (mRNA). With low complexity (no prophylaxis), 28% of the animals in the Wistar and 50% in the SHR group survived (P=0.17). Tumor necrosis factor-alpha levels were lower in the liver of SHR vs. Wistar rats with PCI (P<0.01). The anti-inflammatory cytokine interleukin (IL)-10 was expressed on a higher level in SHR with PCI compared with Wistar rats (P<0.01). With increased complexity (antibiotic and G-CSF prophylaxis) the survival rate was increased from 50% in Wistar rats to 89% in SHR (P<0.01) and the mRNA expression of IL-6 was decreased in the kidney of SHR (P<0.05). Survival rate was 44% in the DS rats vs. 67% of the Wistar rats (P=0.18). The mRNA expression of tumor necrosis factor-alpha and IL-10 was reduced (P<0.01) by pretreatment in the liver of DS rats with PCI. The hypertensive, genetically distinct SHR and DS rats express different patterns of pro- and anti-inflammatory cytokine levels after PCI. G-CSF and antibiotic prophylaxis increases only in SHR survival and decreases IL-6 mRNA expression in the kidney significantly.
Collapse
Affiliation(s)
- Artur Bauhofer
- Institute of Theoretical Surgery, Philipps-University Marburg, 35033 Marburg, Germany.
| | | | | | | | | | | |
Collapse
|
175
|
Wang JG, Staessen JA, Messaggio E, Nawrot T, Fagard R, Hamlyn JM, Bianchi G, Manunta P. Salt, endogenous ouabain and blood pressure interactions in the general population. J Hypertens 2003; 21:1475-81. [PMID: 12872040 DOI: 10.1097/00004872-200308000-00010] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Experimental data show that ouabain is a modulator of the sodium-potassium pump, which plays an important role in sodium homeostasis and blood pressure regulation. We investigated the distribution of plasma ouabain in the general population in relation to blood pressure and other determinants of sodium homeostasis. METHODS In 379 subjects enrolled in a Belgian population study, we measured plasma ouabain, clinical characteristics including blood pressure, serum and urinary electrolytes, urinary aldosterone excretion, various lifestyle factors, and the Gly460Trp polymorphism of the alpha-adducin gene. Our statistical methods included analysis of covariance and multiple linear regression. RESULTS Plasma ouabain (median, 140 pmol/l) correlated independently and positively with male gender (n = 182, P = 0.002), smoking (n = 116, P = 0.05), urinary potassium excretion (mean 69 mmol/day, P < 0.0001), and mutation of the alpha-adducin gene (n = 161, P < 0.0001). Both before and after adjustment for covariables, continuous as well as categorical analyses revealed a significant interaction (P < or = 0.02) between plasma ouabain and urinary sodium excretion (mean 194 mmol/day) in relation to blood pressure (mean systolic blood pressure/diastolic blood pressure, 123/76 mmHg). In individuals with plasma ouabain values below the median, blood pressure increased by 2.2 mmHg systolic and 1.4 mmHg diastolic for each 50 mmol/day increment in urinary sodium excretion (P < or = 0.01). No association between blood pressure and urinary sodium excretion was found when plasma ouabain exceeded the median. CONCLUSIONS Plasma ouabain behaves as a blood pressure modulating factor, possibly released in response to potassium, either inhibiting the pressor effect of an excessive salt intake or counteracting the depressor action of sodium depletion.
Collapse
Affiliation(s)
- Ji-Guang Wang
- Hypertensie en Cardiovasculaire Revalidatie Eenheid, Departement voor Moleculair en Cardiovasculair Onderzoek, Katholieke Universiteit Leuven, Leuven, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
176
|
Sheridan S, Pignone M, Donahue K. Screening for high blood pressure: a review of the evidence for the U.S. Preventive Services Task Force. Am J Prev Med 2003; 25:151-8. [PMID: 12880884 DOI: 10.1016/s0749-3797(03)00121-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
CONTEXT In 1996, the U.S. Preventive Services Task Force (USPSTF) recommended screening adults for hypertension. Since that time, the published literature on hypertension has expanded rapidly, necessitating a new examination of the evidence supporting screening. OBJECTIVE Update the 1996 evidence review on screening for hypertension. DATA SOURCES The 1996 Guide to Clinical Preventive Services, recent systematic reviews, and focused searches of MEDLINE were used to identify new evidence relevant to detecting and treating hypertension. STUDY SELECTION When a good quality, recent systematic review was available, it was used to summarize previous research; MEDLINE was searched only for more recent articles. Two authors reviewed abstracts (and full texts, if necessary) of potentially relevant articles to determine if they should be included. DATA EXTRACTION One author extracted data from included studies into evidence tables. DATA SYNTHESIS Hypertension can be effectively detected through office measurement of blood pressure. Treatment of elevated blood pressure in adults can reduce cardiovascular events. The magnitude of risk reduction depends on the degree of hypertension and the presence of other cardiovascular risk factors. Available studies have found no important adverse effects on psychological well-being and mixed effects on the absenteeism rates of adults who are screened and labeled as being hypertensive. CONCLUSIONS Substantial indirect evidence supports the effectiveness of screening adults to detect hypertension and treating them to reduce cardiovascular disease.
Collapse
Affiliation(s)
- Stacey Sheridan
- Department of Medicine, Division of General Medicine and Clinical Epidemiology, University of North Carolina-Chapel Hill, 5039 Old Clinic Building, CB 7110, Chapel Hill, NC 27599, USA.
| | | | | |
Collapse
|
177
|
|
178
|
Adab P, Cheng KK, Jiang CQ, Zhang WS, Lam TH. Age-specific relevance of usual blood pressure to vascular mortality. Lancet 2003; 361:1391; author reply 1391-2. [PMID: 12711500 DOI: 10.1016/s0140-6736(03)13063-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
179
|
Murray CJL, Lauer JA, Hutubessy RCW, Niessen L, Tomijima N, Rodgers A, Lawes CMM, Evans DB. Effectiveness and costs of interventions to lower systolic blood pressure and cholesterol: a global and regional analysis on reduction of cardiovascular-disease risk. Lancet 2003; 361:717-25. [PMID: 12620735 DOI: 10.1016/s0140-6736(03)12655-4] [Citation(s) in RCA: 370] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cardiovascular disease accounts for much morbidity and mortality in developed countries and is becoming increasingly important in less developed regions. Systolic blood pressure above 115 mm Hg accounts for two-thirds of strokes and almost half of ischaemic heart disease cases, and cholesterol concentrations exceeding 3.8 mmol/L for 18% and 55%, respectively. We report estimates of the population health effects, and costs of selected interventions to reduce the risks associated with high cholesterol concentrations and blood pressure in areas of the world with differing epidemiological profiles. METHODS Effect sizes were derived from systematic reviews or meta-analyses, and the effect on health outcomes projected over time for populations with differing age, sex, and epidemiological profiles. Incidence data from estimates of burden of disease were used in a four-state longitudinal population model to calculate disability-adjusted life years (DALYs) averted and patients treated. Costs were taken from previous publications, or estimated by local experts, in 14 regions. FINDINGS Non-personal health interventions, including government action to stimulate a reduction in the salt content of processed foods, are cost-effective ways to limit cardiovascular disease and could avert over 21 million DALYs per year worldwide. Combination treatment for people whose risk of a cardiovascular event over the next 10 years is above 35% is also cost effective leading to substantial additional health benefits by averting an additional 63 million DALYs per year worldwide. INTERPRETATION The combination of personal and non-personal health interventions evaluated here could lower the global incidence of cardiovascular events by as much as 50%.
Collapse
|
180
|
Abstract
Many workers have an overly simplistic view of the relationship between salt intake and hypertension. This article attempts a critical evaluation of some of the evidence.
Collapse
Affiliation(s)
- J Ian S Robertson
- Medical Research Council Blood Pressure Unit, Western Infirmary, Glasgow, UK
| |
Collapse
|
181
|
MacGregor GA, He FJ. Long term effects of advice to reduce dietary salt. Front cover was highly misleading. BMJ 2003; 326:222; author reply 222. [PMID: 12543848 PMCID: PMC1125076 DOI: 10.1136/bmj.326.7382.222/a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
182
|
Jürgens G, Graudal NA. Effects of low sodium diet versus high sodium diet on blood pressure, renin, aldosterone, catecholamines, cholesterols, and triglyceride. Cochrane Database Syst Rev 2003:CD004022. [PMID: 12535503 DOI: 10.1002/14651858.cd004022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND One of the controversies in preventive medicine is, whether a general reduction in sodium intake can decrease the blood pressure of a population and thereby reduce cardiovascular mortality and morbidity. In recent years the debate has been extended by studies indicating that reducing sodium intake has effects on the hormone and lipid profile. OBJECTIVES To estimate the effects of low sodium versus high sodium intake on systolic and diastolic blood pressure (SBP and DBP), plasma or serum levels of renin, aldosterone, catecholamines, cholesterol and triglycerides. SEARCH STRATEGY "MEDLINE" and reference lists of relevant articles were searched from 1966 through December 2001. SELECTION CRITERIA Studies randomising persons to low sodium and high sodium diets were included if they evaluated at least one of the above outcome parameters. DATA COLLECTION AND ANALYSIS Two authors independently extracted the data, which were analysed by means of Review Manager 4.1. MAIN RESULTS In 57 trials of mainly Caucasians with normal blood pressure, low sodium intake reduced SBP by -1.27 mm Hg (CI: -1.76; -0.77)(p<0.0001) and DBP by -0.54 mm Hg (CI: -0.94; -0.14) (p = 0.009) as compared to high sodium intake. In 58 trials of mainly Caucasians with elevated blood pressure, low sodium intake reduced SBP by -4.18 mm Hg (CI: -5.08; - 3.27) (p < 0.0001) and DBP by -1.98 mm Hg (CI: -2.46; -1.32) (p < 0.0001) as compared to high sodium intake. The median duration of the intervention was 8 days in the normal blood pressure trials (range 4-1100) and 28 days in the elevated blood pressure trials (range 4-365). Multiple regression analyses showed no independent effect of duration on the effect size. In 8 trials of blacks with normal or elevated blood pressure, low sodium intake reduced SBP by -6.44 mm Hg (CI: -9.13; -3.74) (p < 0.0001) and DBP by -1.98 mm Hg (CI: -4.75; 0.78) (p = 0.16) as compared to high sodium intake. The magnitude of blood pressure reduction was also greater in a single trial in Japanese patients. There was also a significant increase in plasma or serum renin, 304% (p < 0.0001), aldosterone, 322%, (p < 0.0001), noradrenaline, 30% (p < 0.0001), cholesterol, 5.4% (p < 0.0001) and LDL cholesterol, 4.6% (p < 0.004), and a borderline increase in adrenaline, 12% (p = 0.04) and triglyceride, 5.9% (p = 0.03) with low sodium intake as compared with high sodium intake. REVIEWER'S CONCLUSIONS The magnitude of the effect in Caucasians with normal blood pressure does not warrant a general recommendation to reduce sodium intake. Reduced sodium intake in Caucasians with elevated blood pressure has a useful effect to reduce blood pressure in the short-term. The results suggest that the effect of low versus high sodium intake on blood pressure was greater in Black and Asian patients than in Caucasians. However, the number of studies in black (8) and Asian patients (1) was insufficient for different recommendations. Additional long-term trials of the effect of reduced dietary sodium intake on blood pressure, metabolic variables, morbidity and mortality are required to establish whether this is a useful prophylactic or treatment strategy.
Collapse
Affiliation(s)
- G Jürgens
- Department of Internal Medicine and Rheumatology Q 107, Copenhagen University hospital at Herlev, Herlev Ringvej, Herlev, Copenhagen County, Denmark, 2730
| | | |
Collapse
|
183
|
Hooper L, Bartlett C, Davey Smith G, Ebrahim S. Reduced dietary salt for prevention of cardiovascular disease. Cochrane Database Syst Rev 2003:CD003656. [PMID: 12917977 DOI: 10.1002/14651858.cd003656] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Restricting sodium intake in elevated blood pressure over short periods of time reduces blood pressure. Long term effects (on mortality, morbidity or blood pressure) of advice to reduce salt in patients with elevated or normal blood pressure are unclear. OBJECTIVES To assess in adults the long term effects (mortality, cardiovascular events, blood pressure, quality of life, weight, urinary sodium excretion, other nutrients and use of anti-hypertensive medications) of advice to restrict dietary sodium using all relevant randomised controlled trials. SEARCH STRATEGY The Cochrane Library, MEDLINE, EMBASE, bibliographies of included studies and related systematic reviews were searched for unconfounded randomised trials in healthy adults aiming to reduce sodium intake over at least 6 months. Attempts were made to trace unpublished or missed studies and authors of all included trials were contacted. There were no language restrictions. SELECTION CRITERIA Inclusion decisions were independently duplicated and based on the following criteria: 1) randomisation was adequate; 2) there was a usual or control diet group; 3) the intervention aimed to reduce sodium intake; 4) the intervention was not multifactorial; 5) the participants were not children, acutely ill, pregnant or institutionalised; 6) follow-up was at least 26 weeks; 7) data on any of the outcomes of interest were available. DATA COLLECTION AND ANALYSIS Decisions on validity and data extraction were made independently by two reviewers, disagreements were resolved by discussion or if necessary by a third reviewer. Random effects meta-analysis, sub-grouping, sensitivity analysis and meta-regression were performed. MAIN RESULTS Three trials in normotensives (n=2326), five in untreated hypertensives (n=387) and three in treated hypertensives (n=801) were included, with follow up from six months to seven years. The large, high quality (and therefore most informative) studies used intensive behavioural interventions. Deaths and cardiovascular events were inconsistently defined and reported; only 17 deaths equally distributed between intervention and control groups occurred. Systolic and diastolic blood pressures were reduced at 13 to 60 months in those given low sodium advice as compared with controls (systolic by 1.1 mm Hg, 95% CI 1.8 to 0.4, diastolic by 0.6 mm hg, 95% CI 1.5 to -0.3), as was urinary 24 hour sodium excretion (by 35.5 mmol/ 24 hours, 95% CI 47.2 to 23.9). Degree of reduction in sodium intake and change in blood pressure were not related. People on anti-hypertensive medications were able to stop their medication more often on a reduced sodium diet as compared with controls, while maintaining similar blood pressure control. REVIEWER'S CONCLUSIONS Intensive interventions, unsuited to primary care or population prevention programmes, provide only minimal reductions in blood pressure during long-term trials. Further evaluations to assess effects on morbidity and mortality outcomes are needed for populations as a whole and for patients with elevated blood pressure. Evidence from a large and small trial showed that a low sodium diet helps in maintenance of lower blood pressure following withdrawal of antihypertensives. If this is confirmed, with no increase in cardiovascular events, then targeting of comprehensive dietary and behavioural programmes in patients with elevated blood pressure requiring drug treatment would be justified.
Collapse
Affiliation(s)
- L Hooper
- MANDEC, University Dental Hospital of Manchester, Higher Cambridge Street, Manchester, UK, M15 6FH
| | | | | | | |
Collapse
|