Hypertension, Diet and Dietary Sodium in Canada. Why is sodium reduction Controversial?

1
Hypertension, Diet and Dietary Sodium in
Canada. Why is sodium reduction Controversial?

Norm Campbell
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Financial interests in sodium

• Salary support from HSF-CIHR to lead efforts to
  prevent and control hypertension
• Only recent salt based grant was a 25,000 one
  year grant (2012-2013) from the NCE Canadian
  Stroke Network to develop and implement a weekly
  med-line search and review on dietary salt
• I have received 750 to talk on unhealthy eating
  from a Internal Medicine meeting in 2013

3
Academic interests

• Professor of Medicine, Community Health Sciences
  and Physiology and Pharmacology, Libin
  Cardiovascular Institute, OBrien Institute of
  Public Health at the University of Calgary
• -HSFC CIHR Chair in Hypertension Prevention and
  Control
• -Chair of the Canadian Hypertension Advisory
  Committee (of national health and scientific
  organizations) to lead the nongovernmental effort
  to prevent and control hypertension
• -President of the World Hypertension League
• -Co-Chair of the PAHO/WHO Technical Advisory
  Group on Cardiovascular Disease Prevention
  through Dietary Salt Reduction
• -Member of the WHO Nutrition Advisory Group
• Focus on salt was based on assessment of evidence
  of benefit.

4
HSFC CIHR Chair in Hypertension Prevention and
control

• Mandate 2011-2016 to align government and non
  governmental organizations on a Pan Canadian
  Hypertension Framework vision and objectives.
• Develop a systematic approach and committee
  structure for the health care sector to
  successfully advocate for policy changes to
  reduce blood pressure in the Canadian population.
  
• Aligning Canadian public health food policy with
  global best practices.

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Systolic blood pressure greater than 115 mmHg
Figure obtained by cropping a downloaded figure
from http//www.healthdata.org July 8 2014,
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Burden of hypertension in Canada

• 7.4 million adult Canadians with hypertension
• In 2007/8 1100 Canadians a day were diagnosed
  with hypertension
• gt 90 of us are estimated to develop hypertension
  in a average lifespan
• Antihypertensive drug costs of 3 billion
  dollars/year
• Almost half of all people in Canada over age 60
  are taking drugs to control blood pressure
• 20-25 million physicians visits for
  hypertension/year
• Direct health care costs approximately 10 of
  overall health costs
• Societal burden (including indirect costs) are
  estimated to be 4.5 to 15 of GDP in high income
  countries

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Attributable Risk of Lifestyle to Hypertension
Risk factor Approximate attributable risk for hypertension
Increased salt in diet 32
Decreased potassium in diet 17
Overweight 32
Sedentary lifestyle 17
Excess alcohol 3
Dietary fats ?
8
The past and current situationfor hypertension
in Canada
2007 / 2008
16
CHHS 1985-1992
4
14
No impact on prevalence No impact of lifestyle
13
66
21
43
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CHMS Canadian Health Measures Survey
CHMS Canadian Heart Health Survey
Wilkins et al. Health Reports Feb 2010
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Pan Canadian Hypertension Framework
An opportunity to discuss how to improve the
prevention and control of hypertension in
Canada 2011-2020
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Canadian Hypertension Advisory Committee
Canadian Hypertension Advisory Committee Membership
Canadian Association of Cardiovascular Prevention and Rehabilitation
Canadian Cardiovascular Society
 Canadian Council of Cardiovascular Nurses
Canadian Diabetes Association
Canadian Medical Association
Canadian Nurses Association
Canadian Pharmacists Association
Canadian Society of Internal Medicine
Canadian Society of Nephrology
Canadian Stroke Network
College of Family Physicians of Canada
Heart and Stroke Foundation of Canada
Hypertension Canada
Public Health Physicians of Canada

• Committee structure formed to support HSF/CIHR
  Chair mandate
• Comprised of 15 national organizations to
  advance/operationalize Hypertension Framework

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Recommendation Priorities
Recommendation
Build Healthy Public Policy (1)
Re-orient/redesign the health services delivery system
Build partnerships to create supportive environments and evolve the healthcare system (2)
Strengthen community action (3)
Develop personal skills for better self-management
Improve decision support (4)
Optimize information systems (5)
Provincial Priority, Hypertension Canada,
C-CHANGE, Hypertension experts
CHAMP Initiative
Hypertension Canada/HSF
PHAC, Hypertension Canada and new Chair priority
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Priority Areas of Focus
Standardized front of package food labels that
contain health connotations
Policy Statement on Marketing to Kids
Healthy Food in Canada
Important but less urgent
Important Urgent
Reduce the impact of financial interests on
healthy public food policies
Fiscal Policies (Taxation/Subsidies)
Healthy food procurement
Sodium Policy Advocacy
Defining Healthy Food
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Policy Positions
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(No Transcript)
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Highlights of recent national health and
scientific organizations actions on dietary
sodium

• 2006 Blood Pressure Canada (BPC), a coalition of
  27 organizations and the Canadian Stroke Network
  prioritize actions to reduce dietary sodium
• 2006-8 BPC strategic planning committee formed
• 2006-7 BPC policy statement on dietary sodium
  endorsed by 17 national health and scientific
  organizations
• 2007 Health and scientific organizations
  collaborate in Health Canada Sodium Working Group
• 2007 Health and scientific organizations conduct
  work on the impact of dietary sodium on the
  health of Canadians
• 2007- Extensive education programs for health
  care professionals and the public- BPC,
  Hypertension Canada and Canadian Stroke Network
• 2011 Health and scientific organizations write
  public letter of concern to the Prime Minister
  and all elected FPT officials regarding the
  Harper governments lack of support for the Sodium
  Reduction Strategy for Canada created by SWG
• 2013 Strong national health and scientific
  organizations support for L Davies parliamentary
  bill for sodium reduction

CSPI PHAC/Health Canada PTs Food Processing
Industry
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WHO supports sodium reduction

• Internationally, in 2012, the World Health
  Organization following an exhaustive and
  comprehensive review of the clinical
  interventions and cohort studies of populations
• United Nations (independent national reviews,
  political and based on advice of the WHO).
• All but 1 comprehensive scientific organization
  review.
• 31 of 31 surveyed national hypertension
  societies.
• Numerous scientific and health NGOs
• Global Burden of Disease Study estimated 1.65
  million deaths in 2010 from high dietary
  sodium/year.
• - 486 authors from 302 institutions in 50
  countries, indicated to be the strongest
  evidence-based assessment of peoples health
  problems around the world. WHO supported GATES
  funded.

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• There is no credible national or international
  health or scientific organization, I am aware of
  that has stated opposition to sodium reduction to
  lt 2400mg/day and most support lt2000mg/day.
  Canadas upper limit of lt2300 mg sodium/day is
  broadly supported within the Canadian health and
  scientific community. Hypertension Canada
  supports 2000 mg sodium/day

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Who does not support sodium reduction

• The Salt Institute.
• Some of the food processing industry especially
  in the United States.
• Several scientists and clinicians who have long
  histories of close relationships with the salt or
  food industries.
• A few dissident scientists most of whom have
  personally performed research (usually with major
  methodological weaknesses) that do not support
  sodium reduction.

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Generating controversy

• The studies that have created controversy are
  based on weak research design
• Unreliable assessment of sodium intake (e.g. spot
  urine)
• Using extreme variation in dietary sodium over a
  duration of a few days
• Do not address known confounding factors
  (explanations) for the outcomes being tested,
• Control for blood pressure (the main mechanism of
  sodium induced harm),
• Conducted in populations with diseases where
  reverse causality is likely (i.e. sick people eat
  less and die more)

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Generating controversy

• Several controversial studies have been conducted
  by consultants of the Salt Institute (an umbrella
  organization of the salt industry)
• The results of the weak studies have been highly
  leveraged into public attention by the food and
  salt industries

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Sodium Science Challenges

• IOM reports Institute of Medicine of the National
  Academies. Sodium Intake in Populations
  Assessment of Evidence. Strom BL, Yaktine AL,
  Oria M, editors. Report , V-F-44. 2013.
  Washington, D.C. USA, The Academies Press.

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Contextual issues in IOM report

• IOM and the IOM committee are highly respected
  and not perceived or likely to have any bias
  against sodium reduction.
• Hypertension was not considered a primary
  outcome.
• Rapid review requested likely resulted in the
  incomplete review of the quality of evidence.
• Only recent studies, 2003 and after were reviewed
  (hence not comprehensive).
• Focused on high risk people. Most of the studies
  were based on cohort designs in people with
  disease where reverse causality is an expected
  major weakness (sick people eat less and die
  more).
• Most of the speakers at the public session of IOM
  were those who had expressed positions against
  sodium reduction and some had COI.

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IOM report Cohort studies that DO NOT support
reducing dietary sodium on CVD, renal or death
Trials BP adjusted Inadequate baseline sodium assessment Inadequate adjustment of confounding factors Likely reverse causality One or more authors with perceived COI
Cohen 2006 1 24hr diet Physical activity, SES 1
Cohen 2008 1 24 hr diet Physical activity, SES 1
Dong 2010 1 3 days 1
Ekinci 2011 1 24 hr urine 1
Geleijinse 2007 overnight
Larsson 2008 1 FFQ
ODonnell /- Spot urine with many on diuretic 1
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IOM report Cohort studies that DO NOT support
reducing dietary sodium on CVD, renal or death
Trial BP adjusted Inadequate baseline sodium assessment Inadequate adjustment of confounding factors Likely reverse causality One or more authors with COI
Stolarz-Skrzypek 2011 1 24 hr
Tikellis 2013 24 hr 1 1
Lennie 2011 24 hr 1 1
Total 6/10 2/10 4/10 5/10 2/10
Number with at least 1 fatal flaw 10/10 Number
with 2 fatal flaws- 7/10 Trials with J curve
with sodium
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IOM report Cohort studies that DO support
reducing dietary sodium on CVD, or death
Trial BP adjusted Inadequate baseline sodium assessment Inadequate adjustment of confounding factors Likely reverse causality Not applicable to positive studies One or more authors with COI
Cook 2007 Repeated 24hr
Cook 2009 Repeated 24hr
Costa 2012 FFQ 1
Gardener 2012 FFQ
Heerspink 2012 Repeated 24 hr 1
Jafar 2006 FFQ 1
Kono 2011 Multiple urines 1
Supports sodium reduction when adjusted for K
intake
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IOM report Cohort studies that DO support
reducing dietary sodium on CVD, renal or death
Trial BP adjusted Inadequate Baseline sodium assessment Inadequate adjustment of confounding factors Likely reverse causality Not applicable to positive studies One or more authors with COI
Arcand 2011 Multiple day and methods
McCausland 2012 Multiday diary 1
Nagata 2004 FFQ
Takachi 2010 FFQ
Thomas 2011 24 hr
Umesawa 2008 FFQ
Yang 2011 24 hr recall
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IOM report Cohort studies that DO support
reducing dietary sodium on CVD, renal or death
Trial BP adjusted Inadequate Baseline sodium assessment Inadequate adjustment of confounding factors Likely reverse causality Not applicable to positive studies One or more authors with COI
Total 0/14 0/14 5/14 0/14 0/14

• Reverse causation does not impact positive
  findings hence 5/14 would have 1 fatal flaw and
  none more than 1

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Cohort studies- conclusion

• If the studies that have fatal flaws are excluded
  then all cohort studies find sodium intake
  associated with CVD, renal or death.
• Through selection of confounding factors and
  their adjustment, the results can be selected.
• Both studies with the senior author who had COI
  have been refuted.
• IOM contrasts with WHO-Cochrane meta analysis of
  cohort studies that used quality indicators to
  exclude methodologically weak and irrelevant
  studies found higher sodium intake was associated
  with a 24 higher risk of stroke, a 63 higher
  risk of stroke death and a 32 higher risk of
  coronary heart disease death. Aburto NJ,
  Ziolkovska A, Hooper L, Elliott P, Cappuccio FP,
  Meerpohl JJ. Effect of lower sodium intake on
  health systematic review and meta-analyses. BMJ
  2013 346f1326

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Heart failure RCT in IOM report

• Series of 6 single centre study publications
• Extreme doses of diuretic used to sodium deplete
  people with heart failure prior to sodium
  reduction
• Meta analysis of studies withdrawn as 4
  publications contain duplicate data
• It was claimed the data was lost for two 2
  studies when verifying data was requested
• Only 1 trial registered
• No safety monitoring board
• 5 complex studies with over 1000 participants -no
  stated funding
• The academic institute where the investigator
  resides declined a formal investigation

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Sodium science

• The use of weak methods indicate the need for
  research standards to be set.
• There is a need for a high quality RCT.
• To me the enthusiastic claims to media that
  sodium is not important for health based on frail
  methods is endangering programs designed to save
  millions of lives/year.

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Science of Salt Weekly

• Science of Salt Weekly is an initiative of the
  (CIHR/HSFC) Chair in Hypertension Prevention and
  Control.  
• Funding for this 2-year initiative has been
  provided by the Canadian Stroke Network and
  the George Institute for Global Health.
• This weekly newsletter features short summaries
  of relevant Medline-retrieved articles related to
  dietary sodium.
• To download issues or to sign-up for automated
  email updates, visit http//www.hypertensiontalk.
  com

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Setting Research standards

• An international coalition of organizations lead
  by the World Hypertension League is forming to
  set research standards and maintain regular
  systematic reviews of the literature

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Some Best Global Practices to achieve the WHO
target (lt5 g salt/day) and United Nations target
(30 decrease in dietary salt by 2025).

• Regulatory approaches that set targets and
  timelines on sodium content of processed foods
  (South Africa and Argentina)
• Voluntary approaches that set targets and
  timelines on sodium content of processed foods
  with close government oversight and monitoring
  (Finland, England, Ireland, Brazil, Chile
  (expected soon to be regulatory)

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Changes in DBP, salt intake and stroke deaths in
Finland
5600 mg
3360 mg
DBP
Salt
Stroke
Karppanen H et al Progress, Cardiovascular
Disease 20064959-75
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Changes in CVD, blood pressure and salt
consumption in the England 2003-2011
Japan not well evaluated but reduced salt intake,
reduced population BP and reduced stroke
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Sodium science

• A substantive but incomplete evidence base
  indicates the widespread addition of large
  amounts of sodium to food is one of the largest
  public health disasters of industrialization
  killing 1.65 million/yr. in 2010
• Current controversy is largely fueled by weak
  research methods, and financial interests.