1 salt, hypertension & health presenters name institution
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- 1 Salt, Hypertension & Health Presenters name Institution
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- 2 Outline
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- 3 Hypertension: A leading risk factor for death and disability
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- 4 Proportion of deaths attributable to leading risk factors worldwide (WHO 2000) Ezzati et al. WHO 2000 Report. Lancet. 2002;360:1347-60. Attributable Mortality (In millions; total 55,861,000) 087654321 High blood pressure Tobacco High cholesterol Unsafe sex High BMI Physical inactivity Alcohol Indoor smoke from solid fuels Iron deficiency Underweight
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- 5 Organ damage related to hypertension Cerebrovascular disease - transient ischemic attacks - ischemic or hemorrhagic stroke - vascular dementia Hypertensive retinopathy Left ventricular dysfunction Coronary artery disease - myocardial infarction - angina pectoris - congestive heart failure Chronic kidney disease - hypertensive nephropathy GFR < 60 ml/min/1.73 m2) - albuminuria - ESRD/dialysis Peripheral artery disease - intermittent claudication
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- 6 High blood pressure as a cardiovascular risk factor Systolic blood pressure > 115 mmHg causes: overall 50% of heart and stroke 60-70% of strokes Hypertension > 140/90 mmHg causes: heart Failure 50% heart attack 25% kidney failure 20%
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- 7 Risk of hypertension increases with age Risk of Hypertension % 0 2 4681012 14161820 Years to Follow-up Women Risk of Hypertension % Years to Follow-up 0 2 4681012 14161820 Men JAMA. 2002: Framingham data. 100 80 60 40 20 0 100 80 60 40 20 0 Future risk in normotensive women and men aged 65 years
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- 8 Risk of stroke mortality increases with age Systolic blood pressure (mm Hg) Prospective Studies Collaboration. Lancet. 2002;360:1903-13. 80-89 years 70-79 years 60-69 years 50-59 years
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- 9 Lifestyle risk factors for hypertension high dietary salt intake obesity high alcohol intake physical inactivity smoking inadequate vegetable and fruit intake inadequate milk product intake
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- 10 In summary Hypertension is a leading risk factor for death and disability. Hypertension is a major cardiovascular risk factor. Hypertension is very prevalent and has a large impact on health care resource use. Lifestyle factors influence blood pressure including dietary salt.
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- 11 Salt, Sodium & Hypertension
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- 12 Higher dietary salt increases death from stroke in the EU Adapted from Perry IJ et al. J Hum Hypertens. 1992;6:23-25.
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- 13 High salt intake increases risk of death CHD Death CVD Death All Death 1.75 1.50 1.25 1.00 0.75 0.50 Hazard Ratio High salt intake Lower salt intake He FJ, MacGregor GA. J Hum Hypertens. 2002;16:761-70.
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- 14 International scientific and health organizations conclude that high dietary salt: increases blood pressure is a health risk WHO/FAO technical report recommends less than 5 g of salt per day Nishida C et al. Public Health Nutr. 2003;7:245-50. WHO/FAO technical report recommends less than 5 g of salt per day Nishida C et al. Public Health Nutr. 2003;7:245-50.
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- 15 Dietary salt blood pressure in animal research
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- 16 Excess salt intake raises blood pressure in animals Rats Pigs Mice Dogs Rabbits Chickens Baboons Chimpanzees Green monkeys Spider monkeys Such studies provide us with detailed information regarding how salt may affect blood pressure its time course underlying mechanisms what to expect in humans
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- 17 Animal studies suggest: Van Vliet et al, 2006 Excess salt intake can cause a slow and progressive increase in blood pressure. In time, salt restriction may not fully restore blood pressure to original levels. Acute salt restriction may underestimate the accumulated effects of lifelong salt exposure.
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- 18 Excess salt intake increases morbidity and mortality in animals Morbidities cardiac hypertrophy vascular hypertrophy vascular stiffening renal damage hyperlipidaemia insulin resistance Mortality hypertensive encephalopathy stroke heart failure premature death Progressive (left to right) effect of salt exposure on LVH in salt sensitive (DS, top row) vs salt resistant (DR, bottom row) rats. From Inoko Am J Physiol. 1994;267:H2471-82.
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- 19 Animal studies summary The ability of excess salt to raise blood pressure appears to be a general characteristic in mammals, including humans. The effects of salt on blood pressure are complex, having several distinct components: - acute vs slow-progressive; - reversible vs irreversible. Many individual systems and mechanisms contribute to the effect of salt on blood pressure.
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- 20 Renal Mechanisms for Salt-Dependent Hypertension
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- 21 Renal mechanisms for salt-dependent hypertension Acute high salt intake - renal retention of fluid blood pressure Chronic high salt intake - resets renal threshold for salt excretion less salt excretion - peripheral resistance - subnormal vasodilation to salt load Nat. Med. 2008 14:64
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- 22 Acute salt sensitivity of blood pressure Salt sensitivity is well defined by the steady state relationship between salt intake and blood pressure (chronic pressure natriuresis relationship, or renal function curve).
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- 23 intrauterine growth retardation (IUGR) low nephron mass renal disease inflammation, injury, etc genetic abnormalities exogenous agents (e.g. DOCA) ageing - salt excretion Factors that lead to salt sensitivity of blood pressure
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- 24 Evidence in Humans for a Link between High Dietary Salt & Hypertension
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- 25 Lower salt reduces systolic blood pressure 4 2 0 -2 -4 -6 -8 -10 -12 - 30 -50-70-90-110 -130 Change in Urinary Salt (mmol/24h) Change in Systolic Blood Pressure (mmHg) Normotensives Hypertensives He FJ, MacGregor GA. J Hum Hyptens. 2002;16:761-70.
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- 26 Effect of longer-term modest salt reduction on blood pressure: meta-analysis* Cochrane Review criteria for sodium studies to include in analysis: random allocation of subjects to treatment/control groups >920 mg/day reduction in dietary sodium >4 weeks duration no concomitant interventions Hypertensive subjects (20 trials), median age 50 (range 24-73) Normotensive subjects (11 trials), median age 47 (range 22-67) * He FJ, MacGregor GA. Cochrane Database of Syst Rev. 2004;Issue 1. Art. No.: CD004937.
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- 27 Lower dietary salt reduced blood pressure in hypertensive adults 20 trials, 802 individuals dietary salt lowered by 4.5 g/day from baseline of 7 - 11 g/d to 3.25 7.2 g/d blood pressure lowered by 5.1/2.7 mm Hg He FJ, MacGregor GA. Cochrane Database of Syst Rev. 2004;Issue 1. Art. No.: CD004937.
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- 28 Lower dietary salt reduces blood pressure in normotensive adults 11 trials, 2,220 subjects dietary salt lowered by 4.25 g/day from baseline of 7.25 11.5 g/d to 3.25 7.75 g/d blood pressure lowered by 2.0/1.0 mm Hg He FJ, MacGregor GA. Cochrane Database of Syst Rev. 2004;Issue 1. Art. No.: CD004937.
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- 29 Effects of salt reduction on blood pressure over time Obarzanek E et al. Hypertension. 2003;42:459-67.
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- 30 Lower salt as part of a healthy diet Methodology randomized 412 adults (mixed blood pressure status, racial groups, sexes) to: control diet - low in fruit, vegetables and dairy, fat content typical of US diet DASH diet - high in fruit, vegetables and low-fat dairy, reduced fat content consume diet for consecutive 30 day periods in random order at each of 3 levels of salt DASH-Sodium Collaborative Research Group. N Engl J Med. 2001;344:3-10.
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- 31 Results: diet and salt intake DASH-Sodium Collaborative Research Group. N Engl J Med. 2001;344:3-10. InterventionChange in mean blood pressure vs control (systolic) Control dietDASH diet 9 g/d saltcontrol level- 6 mmHg 6 g/d salt- 2 mmHg- 7 mmHg 3 g/d salt- 7 mmHg- 9 mmHg
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- 32 Salt restriction reduces blood pressure in children and infants Children (average age 13) reduced dietary salt 42% reduced blood pressure 1.17/1.29 mmHg Infants (less than one year) reduced dietary salt 54% reduced systolic blood pressure 2.47 mmHg Hypertension. 2006;48:861-9.
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- 33 In summary High dietary salt increases blood pressure, which is a health risk. Lower salt consumption decreases blood pressure. Other dietary factors can also reduce blood pressure.
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- 34 The Importance of Lower Salt Intake
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- 35 Healthcare cost savings in Canada by reducing dietary sodium Using the Cochrane Review data a reduction in average dietary sodium intake by 4.5g/d (from 8.8g to 4.3g in Canada) would result in 30% fewer people with hypertension almost double the blood pressure treatment and control rate hypertension care cost savings of $430 to $538 million/yr Can J Cardiol. 2007;23:437-43.
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- 36 Impact of reducing blood pressure through dietary sodium Annual reduction in incidence of myocardial infarction (5%
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