Transcript Hypertension and Salt A call to action

Salt, Hypertension & Health
Presenters name
Institution
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Outline
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Hypertension:
A leading risk factor for death
and disability
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Proportion of deaths attributable to leading risk
factors worldwide (WHO 2000)
0
1
2
3
4
5
6
7
8
Attributable Mortality
(In millions; total 55,861,000)
Ezzati et al. WHO 2000 Report. Lancet. 2002;360:1347-60.
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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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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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Risk of hypertension
increases with age
Risk of Hypertension %
Risk of Hypertension %
100
100
Women
80
80
60
60
40
40
20
20
0
0
2
4
6
8
10
12
14
Years to Follow-up
16
18
20
0
Men
0
2
4
6
8
10
12
14
16
18
20
Years to Follow-up
Future risk in normotensive women and men aged 65 years
JAMA. 2002: Framingham data.
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Risk of stroke mortality
increases with age
80-89 years
70-79 years
60-69 years
50-59 years
Systolic blood pressure (mm Hg)
Prospective Studies Collaboration.
Lancet. 2002;360:1903-13.
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Lifestyle risk factors for hypertension
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•
•
•
•
•
•
high dietary salt intake
obesity
high alcohol intake
physical inactivity
smoking
inadequate vegetable and fruit intake
inadequate milk product intake
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In summary
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•
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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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Salt , Sodium & Hypertension
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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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High salt intake increases
risk of death
CHD
Death
CVD
Death
All
Death
1.75
Hazard Ratio
1.50
High salt
intake
1.25
1.00
Lower salt
intake
0.75
0.50
He FJ, MacGregor GA. J Hum Hypertens. 2002;16:761-70.
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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.
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Dietary salt  blood pressure
in animal research
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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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Animal studies suggest:
• 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.
Van Vliet et al, 2006
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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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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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Renal Mechanisms
for Salt-Dependent
Hypertension
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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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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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Factors that lead to salt sensitivity
of blood pressure
• intrauterine growth retardation (IUGR)
• low nephron mass
• renal disease
 inflammation, injury, etc
• genetic abnormalities
• exogenous agents (e.g. DOCA)
• ageing -  salt excretion
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Evidence in Humans for a Link
between
High Dietary Salt & Hypertension
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Change in Systolic Blood Pressure
(mmHg)
Lower salt reduces
systolic blood pressure
4
2
0
-2
-4
Normotensives
-6
-8
Hypertensives
-10
-12
-30
-50
-70
-90
-110
-130
Change in Urinary Salt
(mmol/24h)
He FJ, MacGregor GA. J Hum Hyptens. 2002;16:761-70.
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Effect of longer-term modest salt reduction
on blood pressure: meta-analysis*
Cochrane Review criteria for sodium studies to
include in analysis:
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•
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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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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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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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Effects of salt reduction on
blood pressure over time
Obarzanek E et al. Hypertension. 2003;42:459-67.
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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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Results: diet and salt intake
Intervention
Change in mean blood pressure vs control
(systolic)
Control diet
DASH diet
9 g/d salt
control level
- 6 mmHg
6 g/d salt
- 2 mmHg
- 7 mmHg
3 g/d salt
- 7 mmHg
- 9 mmHg
DASH-Sodium Collaborative Research Group. N Engl J Med. 2001;344:3-10.
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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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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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The Importance of
Lower Salt Intake
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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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Impact of reducing blood pressure
through dietary sodium
• Annual reduction in incidence of
– myocardial infarction (5%)
– strokes (13%)
– heart failure (17%)
• Reduction in health care costs associated with
the overall predicted 8.6% reduction in CVD
– $1.7 billion per year in Canada and $18 billion in
the United States
Can J Cardiol. 2008;24:497-501.
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Observed effect of lower salt
intake on cardiovascular events in
TOHP trials
• 25-30% lower risk of cardiovascular events
in those who had been in the low salt
groups
• 1.9 -2.5 g/day reduction in dietary salt
during intervention
BMJ. 2007;334:885-92.
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Changes in diastolic blood pressure,
salt intake and stroke deaths in Finland
5600 mg
3360 mg
DBP
Salt
Stroke
Karppanen H et al. Progress, Cardiovascular Disease. 2006;49:59-75.
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Salt intake and obesity
• High dietary salt increases thirst and fluid
consumption.
• Many of the fluids consumed contain simple sugars
or alcohol and contribute to caloric intake.
• 20-30% of the excess calories consumed by children
and adolescents are through increased beverage
consumption associated with high salt intake.
• Therefore high salt diets are likely to be a significant
factor in the obesity epidemic.
He FJ et al. Hypertension. 2008;51:629-34.
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Relationship between salt intake and fluid
consumption in children and adolescents
R=0.40
p<0.001
He FJ et al. Hypertension. 2008;51:629-34.
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Salt and other health effects
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obesity and related diseases (e.g. diabetes)
asthma
kidney stones
osteoporosis
gastric cancer
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How much salt do we need ?
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Dietary salt intake for adults
• In Canada and the USA
– 3.25 - 3.75 g/day (age dependant) is estimated to
be adequate for most adults (adequate intake (AI))
– 5.75 g/day is above the upper limit recommended
for health (upper limit (UL))
• WHO/FAO technical report has indicated dietary salt
intake should be less than 5 g/day
DRI, IM 2003
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Prevalence of excessive intakes:
What we eat in America, NHANES 2001-2002
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Where in our diet does salt come from?
In regions where most food
is processed or eaten in
restaurants
11%
12%
77%
• 12% natural content of
foods
• “hidden” salt: 77% from
processed food –
manufactured and
restaurants
• “conscious” salt: 11%
added at the table (5%)
and in cooking (6%)
Occurs Naturally in Foods
Added at the Table or in Cooking
Restaurant/Processed Food
J Am College of Nutrition. 1991;10:383-93.
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Where in our diet does salt come
from?
• In regions where most food is prepared
and eaten at home, large amounts of salt
may be added in cooking or at the table.
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Salt in our food: why?
• boosts flavor, texture and shelf life of foods
• salt and sodium phosphates increase water
binding capacity of meat products
• salty snacks make you thirsty!
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Our taste for salt:
would we miss it ?
• Taste buds get used to high salt levels.
• As salt levels are gradually reduced taste
buds adapt.
• Only takes a few weeks to enjoy food with
less salt and reveal subtle flavors.
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In summary
 In the Americas, people consume an unhealthy
amount of salt.
 This can cause hypertension, a leading risk for
death and disability.
 The solution is to reduce salt in commercially
manufactured food and promote healthy eating.
 We need to educate the public and patients.
 We need to provide leadership in our
communities.
 The outlook for improvement is cautiously
optimistic.
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Key messages
 Dietary salt is an important contributor to high
blood pressure.
 Reducing salt lowers blood pressure and
prevents cardiovascular disease.
 Salt intake in the Americas is higher than the
levels recommended for health.
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Key messages
 Policies to reduce population-wide salt
intake are most effective and can have a
high impact.
 Healthcare professionals can play a key role
in educating people of all ages regarding
their optimal dietary salt intake.
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Success stories for reducing dietary salt
• Finland (1970)
–
Karppanen H, Mervaala E. Sodium intake and hypertension. Prog Cardiovasc Dis
2006; 49: 59–75; Laatikainen T et al. Sodium in the Finnish diet: 20-year trends in
urinary sodium excretion among the adult population. Eur J Clin Nutr 2006; 60: 965–70.
• UK (1996)
– Food Standards Agency
• http://www.food.gov.uk/healthiereating/salt/
– CASH – Consensus Action on Salt and Health
• http://www.actiononsalt.org.uk/
• WASH (2005) –World Action on Salt and
Health
–
http://www.worldactiononsalt.com/
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Global initiatives
 Success of WASH raising public, political and
manufacturers’ awareness
 WHO Technical Meeting statement on “Reducing
salt intake in populations”
 Agreement of major global food and beverage
manufacturers to cut salt in their foods products
 World Hypertension Day 2009 theme “Salt and
Hypertension” – a massive global public health
campaign to reduce dietary salt through a variety
of initiatives including food sector and other
stakeholders’ participation
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Reducing salt intake
• Most dramatic impact will be to reduce
hidden salt in manufactured foods
• Reduction can be achieved by
– gradual reduction of salt by food manufacturers
and restaurateurs
– a public campaign on health benefits of salt
reduction
– raising consumer attention to salt levels on food
labels
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Anticipated outcomes
• increased consumer awareness of the health
dangers of high dietary salt
• increased consumer demand for lower salt foods
• increased development of lower salt foods by the
food sector
• increased government monitoring of dietary salt
as a health parameter
• gradual reduction in dietary salt such that most
people are below the upper limit (by 2020)
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PAHO/WHO
Cardiovascular Disease Prevention
through Dietary Salt Reduction
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PAHO/WHO
Cardiovascular Disease Prevention
through Dietary Salt Reduction
• PAHO has established a Regional Experts
Group
– international leaders in nutrition and chronic
diseases
– developed a policy statement
– with a view to commitment and implementation by
stakeholders
• who is willing to do what
• what resources are required
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Policy Goal
A gradual and sustained drop in dietary salt intake to
reach national targets or the internationally
recommended target of less than 5g/day/person by
2020.
Recommendations for Policy and Action
• Consistent with the three pillars for successful dietary
salt reduction published by WHO: product
reformulation; consumer awareness and education
campaigns; and environmental changes to make
healthy choices the easiest and most affordable
options for all people.
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To national governments
• Seek endorsement for the PAHO dietary salt
reduction policy statement from ministries of
health, agriculture and trade, from food
regulatory agencies, national public health
leaders, non-governmental organizations,
academia, and relevant food industries.
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To national governments
•Develop sustainable, securely funded, scientifically
based salt reduction programs that are integrated into
existing food, nutrition and health education programs.
The programs should be socially inclusive and include
major socioeconomic, racial, cultural, gender and age
subgroups and specifically children. Components should
include:
– Standardized food labels that easily identify high and
low salt foods.
– Educating people including children about the health
risks of high dietary salt and how to reduce salt intake
as part of a healthy diet.
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To national governments
• Initiate collaboration with relevant domestic food
industries to set gradually decreasing targets, with
timelines, for salt levels according to food categories,
by regulation or through economic incentives or
disincentives with government oversight.
• Regulate or otherwise encourage domestic and
multinational food enterprises to adopt a) best in
class (salt content to match the lowest in the specific
food category) and b) best in world (salt content to
match the lowest in a specific food produced by the
company elsewhere in the world) formulations for
products in national markets.
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To national governments
• Develop a national surveillance system with
regular reporting of dietary salt intake levels
and the major sources of dietary salt. Monitor
progress towards reducing intake to the reach
the international target or a national one.
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To national governments
• Review national salt fortification policies and
recommendations to be in concordance with the
recommended salt intake.
• Extend official support to the Codex Alimentarius
Committee on Food Labeling for salt/sodium to be
included as a mandatory component of nutrition
labels.
• Develop legislative or regulatory frameworks to
implement the WHO recommendations on advertising
of food products and beverages to children.
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To nongovernmental organizations, healthcare
organizations, associations of health
professionals, consumers’ associations
• Endorse the PAHO dietary salt reduction policy
statement.
• Educate memberships on the health risks of high
dietary salt and how to reduce salt intake. Encourage
involvement in advocacy. Monitor and promote
presentations on dietary salt at national meetings and
the publication of articles on dietary salt reduction.
• Promote and advocate media releases on dietary salt
reduction to reach the public, including children and
particularly women given their integral roles in family
health and food preparation.
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To nongovernmental organizations,
healthcare organizations, associations of
health professionals, consumers’
associations
• Broadly disseminate relevant literature.
• Educate policy and decision makers on the health
benefits of lowering blood pressure among
normotensive and hypertensive people, regardless of
age.
• Advocate policies and regulations that will contribute
to population-wide reductions in dietary salt.
• Promote coalition-building, increase organizational
capacity for advocacy and develop advocacy tools to
promote civil society actions.
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To the food industry
• Endorse the PAHO dietary salt reduction policy statement.
• Make current best in class and best in world low salt
products and practices universal across global markets as
soon as possible. Make salt substitutes readily available at
affordable prices.
• Institute reformulation schedules for a gradual and
sustained reduction in the salt content of all existing saltcontaining food products, restaurant and ready-made
meals to contribute to achieving the policy goal. Make all
new food product formulations inherently low in salt.
• Use standardized, clear and easy-to-understand food
labels that include information on salt content.
• Promote the health benefits of low salt diets to all peoples
of the Americas.
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To PAHO
• Ensure good communications and information sharing
between regional and international initiatives to foster best
practices.
• Develop a template for national report cards and report to
Member States on comparative national baselines and
progress at pre specified time points (e.g. in 2010 the
baseline, progress in 2015 and 2020).
• Work with Member States to monitor dietary salt
consumption.
• Develop and foster a network of endorsing governments,
NGOs, and expert champions on dietary salt in the region.
• Develop a web based ‘toolbox’ with educational materials
and programs on dietary salt for the public, patients,
healthcare professionals that are culturally appropriate to
subregions of the Americas.
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To PAHO
• Develop and advocate conflict of interest
guidelines to assist health organizations and
scientists in the region in their interactions with
the food industry.
• Foster research on the economic and health
impacts of high dietary salt in the countries and
sub-regions.
• Assist Member States to revise national and
subregional fortification programs to be
consistent with efforts to reduce dietary salt.
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To PAHO
• Collaborate with FAO, UNICEF, the Codex
Alimentarius Commission and other relevant UN
bodies to achieve a consistent and coordinated
approach to reducing dietary salt.
• Educate policy and decision-makers on the
health benefits of lowering blood pressure among
normotensive and hypertensive people,
regardless of age.
• Advocate policies and regulations that will
contribute to population-wide reductions in
dietary salt.
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Where can I get resources?
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•
•
•
•
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•
•
•
•
•
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www.lowersodium.ca
www.sodium101.ca
Hypertension website
www.hypertension.ca
Consensus Action on Salt & Health (CASH)
www.actiononsalt.org.uk
World Action on Salt &Health (WASH)
www.worldactiononsalt.com/
World Health Organization (WHO)
www.who.int/dietphysicalactivity/reducingsalt/en
Pan American Health Organizaiton (PAHO)
www.paho.org/cncd_cvd/salt
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Resources
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Resources
WHO Forum on Reducing Salt Intake in
Populations (2006: Paris, France)
Reducing salt intake in populations:
Report of a WHO Forum and Technical
Meeting.
5-7 October 2006, Paris, France.
1.
2.
3.
4.
5.
Sodium chloride, dietary – adverse effects
Hypertension – prevention and control
Iodine – deficiency
Nutrition policy
National health programs – organization and administration
I.
II.
III.
World Health Organization
WHO Technical Meeting on Reducing Salt Intake in Populations (2006: Paris, France)
Title
ISBN 978 92 4 159537 7
(NLM classification: QU 145)
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Resources
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