Rates of high blood pressure, diabetes, and heart disease vary among people of different backgrounds.
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By Harvard Health Publications
As an adult living in the United States, you’re more likely to die from heart disease than any other cause, regardless of your racial or ethnic heritage. But people in certain minority groups face a greater risk of dying from cardiovascular disease than others. These differences appear to stem from an increased prevalence of high blood pressure, diabetes, and obesity seen in some populations compared with white Americans.
But teasing out the reasons for this finding isn’t easy. Genetic differences do exist. But diversity within different racial and ethnic groups means that genetic traits common to some groups can’t be generalized to an entire race (see “Understanding ethnic and race categories in the United States”).
Many complex, intertwined factors likely contribute to the higher heart disease rates seen among some groups. Their lower average income level affects where they live, which in turn affects their access to healthy food, safe places to exercise, and quality health care. In other words, “your ZIP code is more important than your genetic code,” says Dr. Eldrin Lewis, a cardiologist at Harvard-affiliated Brigham and Women’s Hospital.
Understanding ethnic and race categories in the United States
Ethnicity refers to groups of people who share a geographic area, religion, culture, or language. The two main ethnic groups in United States are classified as either “Hispanic or Latino” or “not Hispanic or Latino.” Hispanics and Latinos (17%)* trace their origins to Spanish-speaking countries. But they can belong to the white, black, Native Indian, or Asian races.
Race refers to common characteristics passed down through the genes. Non-Hispanic whites (63%) have roots in Europe, the Middle East, or North Africa. Blacks (13%) have origins in any of the black racial groups of Africa or Afro-Caribbean countries. Asians (5%) may have ancestors anywhere from India to Japan. This geographic diversity within racial groups means that there are actually greater genetic differences within than between certain groups.
* Percentages are approximate values from the latest U.S. census.
African Americans at risk
But even after adjustment for factors related to socioeconomic differences, disparities in rates of heart disease and its risk factors persist, Dr. Lewis says. In the United States, nearly half of all black adults have some form of cardiovascular disease, compared with about one-third of all white adults. A genetic difference that predisposes blacks to high blood pressure might play a role.
Some researchers suspect that people who lived in equatorial Africa developed a genetic predisposition to being salt-sensitive, which means their bodies retain more sodium. This condition increases blood volume, which, in turn, raises blood pressure. Salt sensitivity can be beneficial in a hot, dry climate because it allows the body to conserve water. Generations later, however, the American descendants of these individuals remain disproportionately salt-sensitive.
The Hispanic paradox
Hispanics and Latinos have higher rates of obesity, diabetes, and other cardiovascular risk factors compared with whites. “Yet they appear to have lower rates of heart disease, which is counterintuitive,” says Dr. Enrique Caballero, who directs the Latino Diabetes Initiative at the Harvard-affiliated Joslin Diabetes Center. A recent report from the Centers for Disease Control and Prevention (CDC) found that despite facing worse socioeconomic barriers (including low rates of health insurance), Hispanics were about 25% less likely to die of heart disease than whites. This so-called Hispanic paradox isn’t well understood and may reflect underreporting of heart disease rates as well as possible inaccuracies on death certificates as to cause of death, notes Dr. Caballero. Hispanics were about 50% more likely to die of diabetes than whites in the CDC report.
Asian Indians, Chinese, and Filipinos are the three largest of the seven subgroups of Asian Americans in the United States. Among these groups, heart disease rates vary widely. South Asians tend to have higher rates of coronary artery disease. In general, recent immigrants from East Asian countries tend to have lower rates of heart disease than other Americans. However, their children—who often adopt Western cultural practices—have higher rates of obesity and other cardiac risk factors, which underscores the role of lifestyle habits on heart health, notes Dr. Lewis.
“While we recognize and embrace the differences that come with race, the biological differences between people are, for the most part, not as great as the environmental influences that may influence health,” says Dr. Lewis.