- Heart disease is responsible for 1 in 5 deaths in the United States.
- The risk and associated mortality of coronary heart disease, the most common form of heart disease, differ by ethnicity and race.
- New research has shown that accepted risk predictors for coronary heart disease are not appropriate for predicting the disease in all ethnic groups.
- In the study, low levels of high-density lipoprotein (HDL) were associated with an increased risk of disease among white Americans, but not among blacks or African Americans.
According to the Centers for Disease Control and Prevention (CDC), heart disease is responsible for one in five deaths in the United States, up from approximately 697,000 deaths in 2020. Coronary heart disease (CHD) is the most common type of heart disease, affecting over 10% of adults over 45.
CHD affects racial/ethnic groups differently, with the highest rate among white Americans (11.4%), followed by blacks or African Americans (10%), Hispanics (8.8%), and 6.3% among Asian and Pacific Islands. Although they have lower overall CHD levels and a lower risk of disease than white Americans, black or African Americans have an increased mortality rate due to CHD.
The disease is characterized by reduced blood supply to the heart. Over time, the arteries that carry blood can narrow due to fatty deposits, known as atherosclerosis.
Cholesterol, fat produced by the liver, is important for healthy cells, but too much can increase the risk of CHD. It is an important component of fatty atheroma deposits.
Race, HDL, and Cardiovascular Health
In the 1970s, the Framingham Heart Study showed that HDL was inversely associated with coronary heart disease (CHD) and that low HDL levels were associated with a high cardiovascular risk.
However, this theory is being challenged by new research led by Dr. Nathalie Pamir, associate professor at Oregon Health & Science University’s OHSU-PSU School of Public Health, and is co-funded by the National Institute of Neurological Disorders and Stroke and the National Institute on Aging.
The study, published in the Journal of the American College of Cardiology, found that “good” cholesterol was not a universal predictor of cardiovascular disease — and among black or African-American adults, low HDL levels were not associated with an increased risk of cardiovascular disease.
Speaking with MNT, Dr. Pamir explained that “while most risk factors were ‘worked out’ in predominantly white, decent European cohorts, it is not clear how these risk factors affect different ethnicities.”
“We asked a simple question about the relationship between HDL-C and CHD outcomes, whether it was different between white and black Americans — the answer is yes, there is a racial effect,” she said.
Using HDL Levels to Predict Heart Disease
To understand whether cholesterol levels can be used to predict CHD risk in all ethnic groups, the researchers measured the levels of the various lipoproteins and CHD in a national study. The prospective LOOK study involved 23,901 participants without coronary heart disease over a period of over 10 years — of whom 57.8% were white and 58.4% were women.
The researchers asked participants about their demographics and medical history and asked them to classify their own race as white or black/African-American. Blood pressure, EKG, blood, and urine samples were all taken during a home visit, and each participant was interviewed every six months during the follow-up period.
During the study, 1,615 events associated with CHD were recorded, including 664 in the black/African American group.
Not surprisingly, LDL and triglycerides were associated with increased CHD in all participants.
Surprisingly, the researchers found that low HDL levels were associated with an increase in CHD among white participants, but not among black or African-American participants. Put simply, “Low levels of HDL-C (good cholesterol) are only bad for white adults, not a value for risk prognosis in black adults,” explained Dr. Pamir.
Dr. Ni commented that when comparing the two groups, African Americans “don’t have a definite sweet spot for HDL cholesterol.”
He added: “Given that African Americans generally have worse cardiovascular outcomes than white Americans, this suggests that other factors could have a greater impact on cardiovascular health, particularly in the presence of other conditions such as high blood pressure, diabetes, and obesity.”