Researchers at the Stanford University School of Medicine performed a study on around 50,000 U.S. Army soldiers on duty between 2011 and 2014. They found that a single copy of sickle cell gene variant is not linked to early death. Thus, the study refuted the finding of a previous study that claimed sickle cell gene variants may lead to premature deaths.

The lead author of the study, Lianne Kurina, PhD, an associate professor of medicine at Stanford, and a team of medical researchers found that sickle cell disease is not associated with elevated risk of dying as thought earlier. The findings of the study were published on August 3 in The New England Journal of Medicine.

Sickle cell disease was found in around 1 in 13 African-Americans. Until now, it was believed that people who carry two copies of the sickle cell gene variant contract the disease, which reduces their lifespan to 40 or 60 years. Moreover, the patients also suffer bouts of intense pain throughout their lives. People who carry only one copy, the sickle cell gene variant have sickle cell trait.

According to earlier studies, sickle cell trait could trigger death due to a condition called exertional rhabdomyolysis, which is a result of breakdown muscle causing molecules to end up in kidney. ER is a risk for on active duty soldiers. However, the study found that soldier in the study did not have any increase in mortality.

"Another critical difference between our study and the earlier, population-based studies is that in our study, we knew the sickle cell status of everyone in the population," said Kurina. The latest study was performed on soldier with their sickle cell status was confirmed via blood tests.

According to a report in News-Medical by Sally Robertson, "People who have this condition carry two copies of the gene for sickle cell disease. Those who carry only one copy of the gene variant are said to have sickle cell trait, which occurs in about 1 in 13 African-Americans."

Previous studies have suggested that sickle cell trait is associated with dire health consequences, including an increased risk of mortality due to a potentially fatal condition called exertional rhabdomyolysis (ER). ER occurs when the breakdown products of damaged muscle tissue build up in the blood and kidneys.

However, in the first longitudinal cohort study of sickle cell trait among African-American soldiers, Lianne Kurina (Stanford) and colleagues have shown that there is no increased risk of death associated with sickle cell trait.

A report published in Sickle Cell Anemia News revealed, "Sickle cell trait, a form of sickle cell caused by one (rather than two) faulty alleles, has long been thought to raise a person’s risk of premature death from muscles breaking down under exertion, straining the kidneys."

Sickle red blood cells have an abnormal crescent shape that is rigid and less able to pass through tight spaces. This may block blood flow to the muscles and other organs, resulting in tissue death, organ failure, and rhabdomyolysis.

Exertional rhabdomyolysis was not exclusively associated with sickle cell trait. Other factors, such as obesity, tobacco use, and recent use of antipsychotic or statin medications were associated with similar or greater risks of muscle breakdown.