Anemia is genetic but not the root cause
When it comes to genetic diseases, the answer to “are you anemic” isn’t always easy to find.
A new study from Johns Hopkins University’s Division of Genetics sheds new light on the genetics of anemia and provides new insight into the disease’s prevalence in the United States.
The researchers used the National Health and Nutrition Examination Survey (NHANES) data to analyze how anemia was diagnosed in the nation’s capital.
The study is the first of its kind in the country and shows anemia is more prevalent in older, white people than in minorities and people of color.
“The findings reveal that a lack of genetic diversity in anemia has consequences in a number of health-related outcomes, including an increased risk of cardiovascular disease, stroke, diabetes, and certain cancers,” said study author Dr. Steven B. Novella, an assistant professor in the Department of Biostatistics and Genetics at Johns Hopkins.
“In this regard, anemia may be a proxy for underlying genetic and metabolic disorders, such as obesity and type 2 diabetes.”
The study, published in the journal PLoS One, looked at the relationship between anemia prevalence and a range of genetic and demographic factors, including ethnicity, gender, age, race/ethnicity, household income, marital status, education, and medical history.
The findings showed that anemia in the U.S. is more common among older white Americans, who are about four times more likely to be diagnosed with anemia than people of other races.
“Anemia is a disease that’s more prevalent among people in older white people, so we thought it was important to understand the genetic contribution to anemia,” Novellas co-author Dr. Eric Hausman, a Johns Hopkins graduate student in the department of biological sciences, told Live Science.
“It was important for us to look at how anemic whites are more susceptible to an illness, as well as their susceptibility to genetic variation.”
The researchers analyzed NHANES data from 2011 to 2014, when an estimated 2.5 million Americans were tested for anemia, a disease characterized by anemia caused by the presence of blood cells that don’t clot.
The data showed anemia rates in the capital increased between 2001 and 2012.
Anemia was more common in people living in census tracts in which the number of black residents was below 5 percent and the median household income was below $30,000.
The rates of anemic white people also increased over the same period, from 7.2 percent in census tract areas with more than 50,000 residents in 2001 to 7.9 percent in the same tracts in 2012.
“There are many ways to look for an individual’s risk for an illness.
For instance, we know that the more your genetic makeup is related to your age and ethnicity, the higher your risk for developing anemia will be,” Novesa said.
“For people with an average age of 65 years, the likelihood of developing an anemia rises with age.
And so, the data show that anemic people have an increased prevalence of an increased incidence of an inherited disease risk factor that’s associated with an increased rate of an overactive immune system, which may increase their susceptibility.”
The authors say that although the prevalence of the disease among older whites is higher than the prevalence among minorities, it is still higher than in other races and in people of all ages.
“We have this stereotype that older white folks are sicker, that they have a higher rate of cardiovascular diseases,” Hausmann said.
But anemia doesn’t have to be a disease to be anemic.
A person with anemic achondroplasia, which means the cells of the bone marrow don’t produce enough oxygen, has a 10 to 20 percent increased risk for death from cardiovascular disease.
An anemia with a high risk of stroke or diabetes also increases an individuals risk for cardiovascular disease and cancer.
“This study shows that an anemic person is more susceptible than someone with normal levels of an enzyme in their bone marrow, which is a marker for an immune system deficiency,” Hsu said.
He added that an increased anemia risk was also associated with lower body mass index (BMI), a marker of body fat.
“So if you have a BMI below 20, it’s going to affect your risk of developing cardiovascular disease,” Hahn said.
However, the researchers found that white people were more likely than other races to have anemia.
“When we looked at an individual with a low risk of an anaerobic muscle cell death, we found that people of African descent had an increased number of anaerobes than Caucasians,” Nong said.
An example of a high anaerobe is a person with a BMI of 25 to 29, and an anker cell death is a death of a cell that helps make blood clot.
Anaerobic cells make up about 10 percent of cells