Transfusion medicine

Blood donation is associated with iron deficiency among both adolescent girls and younger adult women in the United States, according to a study recently published in Transfusion. Eshan U. Patel, M.P.H., from the Johns Hopkins University School of Medicine in Baltimore, and colleagues used data from the 1999 to 2010 National Health and Nutrition Examination Survey to identify girls and women who reported their blood donation history in the preceding year and had serum ferritin (SF) measurements available.

Mitigating iron deficiency

Participants were stratified by age (adolescents, 16 to 19 years: 2,419; adults, 20 to 49 years: 7,228). The researchers found that in both adolescent and adult blood donors, geometric mean SF levels (ng/mL) were lower than in non donors. Similarly; the prevalence of absent iron stores (SF < 12 ng/mL) was higher in blood donors compared with nondonors for both adolescents (adjusted prevalence ratio, 2.03) and adults (aPR, 2.06).

The prevalence of iron deficiency anemia (SF < 26 ng/mL and hemoglobin < 12 g/dL) was also higher in blood donors compared with non donors among both adolescents (aPR, 2.1) and adults (aPR, 1.74). “These national data call for further development and implementation of blood donation practices aimed toward mitigating iron deficiency;” the authors write.

Medical procedure

Red blood cell transfusions are the most common medical procedure provided in hospitals; with more than 100 million units collected worldwide every year for this purpose, according to the World Health Organization. “These results are intriguing and suggest that if you require a transfusion; your clinical outcome may be affecte by the blood donor’s age and sex;” says senior author Dr. Dean Fergusson; a senior scientist and Director of the Clinical Epidemiology Program at The Ottawa Hospital as well as a professor at the University of Ottawa.

“However; it is important to remember that our study was observational in nature; which means it cannot be considered definitive evidence.” The study, published in JAMA Internal Medicine; evaluated the impact of blood donor sex and age on recipient outcomes by linking 30,503 transfusion recipients at The Ottawa Hospital between October 2006 and December 2013 with their respective blood donors (80,755 donors in total).

Associated risk

The average age of the recipients is 66.2 years and their outcomes are follow for an average of 2.3 years with a maximum follow-up time of 7.2 years. Because The researchers find that recipients of female donor red blood cells are associate with an eight percent increase risk of death (from any cause) per unit transfused compare with recipients of male donor red blood cells.
For example; for a recipient that received six units of red blood cells; this would translate into an associated risk of death of 36 percent for recipients of all female donor blood compared to 27 percent for recipients of all-male donor blood one year later. The researchers also found similar associations with red blood cells from younger donors.

Recipients of blood from donors age 17- 20 are associate with an eight % increase risk of death per unit transfuse compare with recipients of red blood cells from donors age 40-50. In addition; recipients of red blood cells from donors age 20-30 were associate with a six percent increase risk of death per transfuse product compare with recipients of red blood cells from donors age 40-50.

Development Scientist

“We need further research to confirm these findings and to look at possible biological mechanisms;” said lead author Dr. Michaël Chassé; an assistant professor at Université Laval and a critical care physician at CHU de Québec Université Laval. “One possibility is that components in the blood of younger donors or female donors ;may affect the immune system of the transfusion recipient.”
“Though our research suggests that we should investigate what’s behind the associations that we found; there is no definitive evidence yet that proves that one type of blood is better or worse for patients;” says Dr. Jason Acker; co-author on the paper and Senior Development Scientist with Canadian Blood Services. Because “This study opens up new areas of investigation where we can really dig into the biological explanations and understand true cause and effect. Therefore In the meantime; patients continue to receive the safest transfusions