What is the question?

• What is the relationship between added sugars consumption and risk of cardiovascular disease?

What is the answer to the question?

• Limited evidence from prospective cohort studies that were based primarily on sugar-sweetened beverages suggests that higher consumption of added sugars in adulthood is associated with increased risk of cardiovascular disease mortality. 
• Insufficient evidence is available to determine the relationship between added sugars consumption and risk of cardiovascular disease in children. 
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and cardiovascular disease risk profile. 
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and risk of stroke. 
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and incident ischemic cardiovascular disease events. 
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and risk of peripheral artery disease. 
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and risk of heart failure. 

Why was this question asked?

• This important public health question was identified by the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) to be examined by the 2020 Dietary Guidelines Advisory Committee.

How was this question answered?

• The 2020 Dietary Guidelines Advisory Committee, Beverages and Added Sugars Subcommittee conducted a systematic review to answer this question with support from the Nutrition Evidence Systematic Review (NESR) team.

What is the population of interest? 

• The population of interest for the intervention/exposure was all ages (birth through older adulthood). 
• The population of interest for the intermediate outcomes was all ages 2 years and older for controlled trials and ages 2-18 years for observational studies. 
• The population of interest for the endpoint health outcomes was all ages 2 years and older.

What evidence was found? 

• This review includes 23 studies: 3 in children, 20 in adults.
• The exposure or intervention of interest was added sugars. This included total added sugars and added sugars from single, substantial sources like sugar-sweetened beverages (SSB).
• Evidence in children: 
  • All 3 studies examined intermediate outcomes, primarily lipid profiles. Two found greater added sugars intake related to worse lipid profiles in children. The third found no relationship.
  • Evidence was limited by the small number of studies, wide variability in participant age, and inconsistency in outcomes measured.
• Evidence in adults: 
  • Four of the 6 articles reporting intermediate outcome data found no relationship with added sugars. The remaining 2 found added sugars related to both total cholesterol and triglyceride levels.
  • Cardiovascular disease-related mortality risk was positively related to greater added sugars intake when the exposure was measured multiple times.
  • No conclusions could be drawn for peripheral artery disease, stroke, or heart failure.
  • Evidence was limited by poor adjustment for confounders, use of different exposures and outcomes, and measuring the exposure only once.

How up-to-date is this systematic review?

• This review searched for studies from September 2014 to September 2019.

Background

• This important public health question was identified by the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) to be examined by the 2020 Dietary Guidelines Advisory Committee.
• The 2020 Dietary Guidelines Advisory Committee, Beverages and Added Sugars Subcommittee conducted a systematic review to answer this question with support from the Nutrition Evidence Systematic Review (NESR) team.
• The goal of this systematic review was to examine the following question: What is the relationship between added sugars consumption and risk of cardiovascular disease?

Conclusion statements and grades

• Limited evidence from prospective cohort studies that were based primarily on sugar-sweetened beverages suggests that higher consumption of added sugars in adulthood is associated with increased risk of cardiovascular disease mortality. (Grade: Limited)
• Insufficient evidence is available to determine the relationship between added sugars consumption and risk of cardiovascular disease in children. (Grade: Grade not assignable) 
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and cardiovascular disease risk profile. (Grade: Grade not assignable)
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and risk of stroke. (Grade: Grade not assignable)
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and incident ischemic cardiovascular disease events. (Grade: Grade not assignable)
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and risk of peripheral artery disease. (Grade: Grade not assignable)
• Insufficient evidence is available to determine the relationship between added sugars intake in adulthood and risk of heart failure. (Grade: Grade not assignable)

Methods 

• A literature search was conducted using 3 databases (PubMed, Cochrane, and Embase) to identify articles that evaluated the intervention or exposure of added sugar consumption and the outcomes of cardiovascular disease. A manual search was conducted to identify articles that may not have been included in the electronic databases searched. Articles were screened by two NESR analysts independently for inclusion based on pre-determined criteria. 
• Data extraction and risk of bias assessment were conducted for each included study, and both were checked for accuracy. The Committee qualitatively synthesized the body of evidence to inform development of a conclusion statement(s), and graded the strength of evidence using pre-established criteria for risk of bias, consistency, directness, precision, and generalizability.

Summary of the evidence

• 23 studies examined the relationship between added sugars consumption and the risk of cardiovascular disease (CVD):
  • Children: 3 studies, including 1 randomized controlled trial (RCT) and 2 prospective cohort studies (PCSs)
  • Adults: 20 studies, including 4 RCTs, 2 cross-over studies, and 14 PCSs
• The added sugars intervention/exposure included:
  • Total added sugars intake from foods and beverages
  • Added sugars from a single substantial source of overall added sugars intake (e.g., sugar-sweetened beverages [SSB], total sucrose intake)
• CVD outcomes considered:
  • Intermediate outcomes: Total cholesterol, LDL-C, HDL-C, triglycerides, and blood pressure (systolic and diastolic)
    • Children: included intermediate outcome data from RCTs and observational studies
    • Adults: included intermediate outcome data from RCTs and cross-over studies only
  • Endpoint outcomes: CVD (including myocardial infarction, coronary heart disease, and coronary artery disease; congestive heart failure; and peripheral artery disease), stroke (separating ischemic and hemorrhagic when possible), venous thrombosis, and CVD-related mortality
    • Children and adults: included endpoint outcome data from RCTs, cross-over, and observational studies
• Evidence in children:
  • Three studies reported on intermediate CVD outcomes in children; no studies looking at endpoint CVD outcomes in children met the inclusion criteria.
  • Findings from the 1 RCT and 1 cohort study found greater added sugars intake related to worse lipid profiles in children, namely detrimental change in total cholesterol and HDL-C over time.
  • The third study did not find a significant relationship between added sugars consumption and CVD outcomes.
  • The body of evidence was limited substantially by the small number of studies, the variability in age of the participants, and inconsistency in outcomes measured.
• Evidence in adults:
  • Intermediate outcomes: 
    • Three RCTs reported in 4 articles and 2 cross-over studies examined intermediate CVD outcomes; 4 of these studies found no significant effect of added sugars consumption.
    • One RCT found that reducing added sugars consumption led to improved triglyceride levels, and the second article from a larger sample of participants from the same RCT found that continued high levels of SSB consumption led to detrimental changes in total cholesterol and triglyceride levels.
    • RCT evidence was limited by small sample sizes and inconsistency in exposures and outcomes measured.
  • Endpoint outcomes: 
    • CVD-related mortality was assessed by 8 PCSs; 6 of the 8 found no significant relationship; 1 found a relationship before adjustment for adiposity, and the other reported repeat exposure assessment in 2 independent cohorts and found a significant, positive association.
    • A small number of studies examined ischemic CVD events, peripheral artery disease, stroke, and heart failure, which limited the ability to draw conclusions. 
    • Most studies adjusted for adiposity, though four studies presented data both with and without adjustment, and all but one found the relationship did not change.
    • Observational evidence was limited by inadequate adjustment for confounders, inconsistency in exposures and outcomes measured, and measures of exposure taken at baseline only.