A latest research led by experts from Stanford University has challenged the previous studies which had long associated sickle cell trait with the risk of premature death. A longitudinal study carried out from 2011 to 2014 on the African American US soldiers have found that sickle cell trait increased the risk of exertional rhabdomyolysis but not of premature death.
Defying all previous evidence which has linked sickle cell trait with premature deaths, this study, which was published recently in the New England Journal of Medicine, has a potential to change our misconceptions about the condition and associated risks.
Exertional Rhabdomyolysis And Sickle Cell Trait
Rhabdomyolysis is a serious syndrome that takes part due to muscle injury, which can be direct or indirect in nature. The condition occurs when the muscle fibers begin to die and their content is released into the bloodstream. When the debris becomes hard for the kidney to process, renal failure can take place, rarely making it fatal.
However, exertional rhabdomyolysis (ER) results from vigorous exercise. Deaths of high profile military personnel and athletes have put the syndrome in the limelight in the past and its underlying link with sickle cell trait is often reported.
On the other hand, sickle cell trait (SCT) is a condition when a person inherits one faulty gene from their parent who has sickle cell anemia or who is a carrier of sickle cell anemia. In this condition, the person does not show symptoms of sickle cell anemia (SCA) which is a blood disorder when beta-globin gene is mutated. In SCA, the disk like circular shape of red blood cells are disrupted and the sickle shaped cells have a low affinity for oxygen.
ER can occur in normal people but the likelihood of SCT carrying people to have ER is slightly increased. In this case, excessive muscular activity depletes the body’s energy currency, ATP, and the exhausted muscular tissues begin to disrupt muscle cell membranes. In prolonged strenuous exercise, exposure to extreme heat and dehydration often leads to ER.
According to the American Society of Hematology, 1 to 3 million Americans suffer from SCT and about 7.3 % of African American population has this condition. While the condition is present in Hispanics, Caucasians from southern Europe origin, South Asians and people from Middle East, the prevalence of the condition is the highest in African origin, which led the researchers to solely experiment African American military personnel.
In this, first of a kind, longitudinal study of SCA in African Americans, physically active soldiers of all ages were recruited to establish the claimed link. Relation of premature death and ER was observed on 47,944 African American participants, according to their SCT status. All of these research participants had undergone tests for HbAS and they were subjected to exertional-injury precautions. All the participants were checked for medical comorbidity and all the confounding factors were excluded from the study to ensure validity of the study.
Interestingly, no significant link with premature death was reported in the participants when compared with soldiers who did not have the sickle cell trait. But this likelihood of ER was lower than obese people who used statins for high cholesterol problems, antipsychotic agents or who smoked tobacco.
The Benefit Of This Study
Before this study, two population-based studies were conducted in the US that showed higher rates associated with sudden exertion-related deaths amongst black football players on national Collegiate Athletic Association (NCAA) Division 1 team. However, the validity of the results was dubious as the sickle cell trait status of the participants was not known.
As a result of these studies, many organizations have started adding precautions while recruiting African Americans as athletes or soldiers. These precautionary measures concerned the American Society of Hematology (ASH) regarding increased discrimination and stigmatization that resulted from mandatory screening tests. It was in 2012 when ASH released a policy statement on the screening for sickle cell trait and athletic participation which opposed the mandatory screening and urged the organizations to adopt universal preventive measures which included proper hydration and rest breaks between long exercise spans.
With the surfacing of this new, more reliable evidence, the misleading association between the condition, strenuous activities and premature death is likely to be changed.
The US military had already introduced universal screening to minimize the element of discrimination and availability of equal opportunities to all the citizens of America. Now, it is time when precautions to contain fatal possibilities of ER should be adopted by all organizations pertaining to athletic, military or other strenuous work. It will help all people lead a secure life without experiencing an episode of ER, and without any discrimination of color or creed.