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Health, United States Spotlight: Racial and Ethnic Disparities in Heart Disease

Health, United States Spotlight: Racial and Ethnic Disparities in Heart Disease (April 2019)

Overview of Heart Disease and Disparities

  • Heart disease is the leading cause of death in the United States.
  • The risk of death from heart disease varies significantly between different racial and ethnic groups.
  • The spotlight focuses on:
    • Deaths
    • Reported prevalence
    • Risk factors associated with heart disease.
  • Four clinical risk factors discussed include:
    • Hypertension
    • Obesity
    • Diabetes
    • High total cholesterol
  • Behavioral risk factors such as smoking and physical inactivity also exhibit disparities by race and ethnicity.

Heart Disease Topic Areas

Deaths

  • Data Source: National Center for Health Statistics (NCHS), National Vital Statistics System (NVSS).
  • Notes:
    • Reporting for racial and ethnic groups other than non-Hispanic White and non-Hispanic Black is often inconsistent on death certificates.
    • Despite this inconsistency, misclassification is minor for Hispanic and non-Hispanic Asian or Pacific Islander groups.

Prevalence

  • Data Source: NCHS, National Health Interview Survey (NHIS).
  • Notes:
    • Prevalence figures are self-reported; respondents indicate if health professionals had diagnosed them with conditions like:
    • Coronary heart disease
    • Angina
    • Heart attack
    • Other heart conditions.

Demographics of Death Rates

Age-adjusted death rates for heart disease (1999-2017):
  • Metrics: Deaths per 100,000 persons
  • Trends indicate:
    • From 1999 through 2017, heart disease death rates declined for all groups; however, the rate of decrease has slowed recently.
    • Non-Hispanic Black individuals were over twice as likely to die from heart disease compared to non-Hispanic Asian or Pacific Islander individuals in both 1999 and 2017.
  • Death rates:
    • 2017:
    • Black, not Hispanic: 337.4
    • White, not Hispanic: 168.9
    • Hispanic: 114.1
    • Asian or Pacific Islander, not Hispanic: 85.5
    • Trend Analysis:
    • Non-Hispanic White adults aged 18 and over:
      • 2017: 11.5% had heart disease (age-adjusted).
      • 1999: Significantly different from other racial groups.
    • Non-Hispanic Black adults aged 18 and over:
      • 2017: 9.5% had heart disease (age-adjusted).
      • 1999: Also significantly different from other groups (stable trend).
    • Hispanic adults aged 18 and over:
      • 2017: 6.0% had heart disease (age-adjusted), stabilized since 1999.

Learning Objectives

  • Explain the relationships between different lipids and chronic diseases such as saturated fats, trans fats, cholesterol, unsaturated fats, and essential fatty acids.
  • List current dietary recommendations for lipid intake.

Regulation of Lipid Metabolism

  • Post-Prandial State (After a Meal):
    • Increased Insulin, decreased Glucagon.
    • Insulin encourages lipogenesis (conversion of excess energy sources into fat, hierarchy: fat > carbohydrates > proteins) and triglyceride storage.
  • Post-Absorptive State (Between Meals):
    • Decreased Insulin, increased Glucagon.
    • Glucagon promotes lipolysis (fat breakdown).
  • Main storage site for lipids is in lipid droplets across different classes of adipocytes (fat storage cells).

Exogenous Lipid Pathway

  • Post-Prandial State:
    • Begins with dietary lipids.
    • Digestion (~75% occurs in the small intestine via pancreatic lipase).
    • Free Fatty Acids (FFA) and glycerol are absorbed by enterocytes, re-esterified, and packed into chylomicrons (CM) along with cholesterol.
    • CM released into lymph capillaries then into bloodstream.
    • In circulation, Lipoprotein Lipase (LPL) removes fatty acids from Triglycerides (TAGs) inside CM, allowing FFA uptake by extrahepatic tissues (e.g., adipose and skeletal tissues) for energy or storage.
    • CM remnants are then absorbed by the liver.

Endogenous Lipid Pathway

  • Post-Absorptive State:
    • Starts at the liver.
    • Newly synthesized FAs or those from extrahepatic tissues are re-esterified into TAGs and packed into Very-Low-Density Lipoprotein (VLDL).
    • In circulation, LPL removes FAs from VLDL, making FFA available to peripheral tissues.
    • FAs can be utilized as energy or undergo oxidation (FFA → Acetyl-CoA).
    • VLDL is converted into Intermediate-Density Lipoprotein (IDL);
    • 2/3 of IDL is taken by the liver, and 1/3 is further metabolized into Low-Density Lipoprotein (LDL).
    • LDL is rich in cholesterol esters, taken up by peripheral tissues via LDL receptors, and can be degraded by^ macrophages or taken back by the liver.

Reverse Cholesterol Pathway

  • High-Density Lipoprotein (HDL):
    • Forms in both liver and small intestines.
    • Transports cholesterol esters from peripheral tissues to the liver, converting them into bile which is the primary excretory route for cholesterol.
    • HDL serves as a repository for transferable apoproteins.

Atherosclerosis and Cardiovascular Disease (CVD)

  • Altered ratios of LDL, HDL, cholesterol, and TAGs are associated with increased risk of atherosclerosis, the primary cause of CVD.
  • LDL (bad cholesterol) delivers cholesterol esters to peripheral tissues.
  • HDL (good cholesterol) collects excess cholesterol esters to return to the liver.

Healthy Blood Lipid Profile

  • Total cholesterol: < 200 mg/dL
  • LDL-cholesterol (LDL-C): < 100 mg/dL
  • HDL-cholesterol (HDL-C): > 60 mg/dL
  • Triglycerides: < 150 mg/dL

Impact of Atherosclerosis

  • Atherosclerosis restricts blood flow:
    • Blocks flow to the brain (causing stroke).
    • Blocks flow to the heart (causing heart attack).

Cardiovascular Disease (CVD)

  • A broad term covering conditions affecting the heart and blood vessels, including:
    • Blood vessel diseases (e.g., coronary artery disease [CAD])
    • Arrhythmias (irregular heart rhythms)
    • Congenital heart defects
    • Heart valve diseases
    • Heart infections
    • Leading global causes of death in 2021, affecting men and women across racial and ethnic groups.

Heart Disease Statistics (2023)

  • Heart disease is the leading cause of death, accounting for
    • 919,032 deaths (1 in every 3 deaths).
    • Cost estimates: ~ $417.9 billion (2020-2021).
    • Coronary heart disease is the most common type, resulting in 371,506 deaths in 2022.
    • Highest prevalence in southern US; increases with age, highest in males.

Risk Factors for Coronary Artery Disease (CAD)

  • Signs/Symptoms include:
    • Shortness of breath
    • Chest pain
    • Fatigue
    • Dizziness
  • Dietary factors influencing CAD include:

- Role of nutrition may improve or worsen CAD depending on dietary choices.

Dietary and Lifestyle Recommendations

  1. Avoid trans fats.
  2. Keep saturated fat < 10% of total energy intake, and increase mono-/polyunsaturated fats.
  3. Maintain a healthy weight.
  4. Avoid smoking.
  5. Exercise regularly.