Demographic, Clinical, and Biochemical Predictors of Pica in High-Intensity Blood Donors


Hefei Liu BS 1,2, Robert T. Burns PhD 1, Bryan R. Spencer PhD 3, Grier P. Page PhD 4, and Alan E. Mast MD, PhD 1,5 1Blood Research Institute, Versiti, Milwaukee, WI 2Medical College of Wisconsin, Wauwatosa, WI 3American Red Cross Scientific Affairs, Dedham, MA 4Research Triangle Institute International, Atlanta, GA 5Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI


Frequent blood donors who contribute multiple times annually are key at maintaining an adequate blood supply, but repeated donations can exacerbate iron deficiency, which could lead to pica, a condition characterized as repeated eating or chewing of a non-nutritious substance such as ice, clay, and dirt. Therefore, understanding donor characteristics will help prevent complications of iron deficiency anemia such as pica secondary to heavy donations and maintain the precious blood supply.


In a cohort of 1,693 high-intensity blood donors, who are defined as giving nine or more units of whole blood in the preceding two years, demographic data, survey questions of pica behaviors and restless legs syndrome (RLS), which is also linked to iron deficiency, complete blood count, and ferritin were collected and analyzed using univariable and multivariable logistic regression analysis. Pica was rigorously defined by questionnaire responses: 1) “Yes” to eating ice and, 2) Consumes “8 oz – 24 oz” or “more than 24 oz” of ice and, 3) at a frequency of “once a day” or “several times a day”. Alternatively, “yes” to eating non-ice substances regardless of amount and frequency was also characterized as pica.


Pica was present in 1.5% of the high-intensity donors, and only occurred in those with ferritin <50 ng/mL. In univariate logistic regression analysis, a general decline in pica behaviors was observed from younger to older donors ranging from 4.3% in 18–40-year-old donors to 0.4% in donors >70 years old (p=0.001). There was no significant association between BMI and pica, but there was a higher prevalence of pica behaviors in obese donors (BMI =30, 2.5%, 14 out of 565) than in normal/underweight (BMI 17.5-25, 1.3%, 6 out of 490) and overweight donors (BMI 25-30, 1.0%, 6 out of 638). Demographic and clinical factors not associated with pica behaviors included sex (p=0.713), donation frequency within previous two-years (p=0.573), smoking in the last 30 days (p=0.747), RLS (p=0.745), hormone supplement use (p=0.986), and iron supplement use (p=0.162). Some CBC parameters associated with iron deficiency anemia were also positively associated with pica. These include a lower hematocrit (HCT, p=0.005), lower mean corpuscular volume (MCV, p<0.001), and higher RBC distribution width (RDW, p=0.007). White blood cell count (WBC, p=0.293)), red blood cell count (RBC, p=0.760), hemoglobin (HGB, p=0.100), and platelet count (PLT, p=0.366) were not associated with pica. Of the sixteen candidate variables analyzed in the forward stepwise multivariate logistic regression model, only hematocrit (OR=0.835, p=0.020) was independently associated with pica.


Blood donation can rapidly deplete a donor's iron stores, with depletion often occurring following 1-2 donations in women and 3-4 donations in men. We have uncovered various predictors of pica in high-intensity donors, which further emphasizes the need to continue to implement iron replacement programs to reduce the prevalence of pica and maintain a robust pool of frequent donors.



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