Statistical Analysis
Calculated Variables and Definitions. Age groups were
defined as young children (3 to 7.9 years), older children and
adolescents (8.0 to 18.9 year), and adults (19 years). Subjects
were categorized as transfused if they were currently
receiving transfusion therapy on a routine basis of eight or
more transfusions during the 12 months before entering the
study. They were categorized as nontransfused if they were
receiving fewer than eight transfusions per year or were not
currently receiving transfusion therapy. Body mass index was
calculated as kilograms of body weight per height in square
meters. Estimated energy requirement (EER) was calculated
for each individual using their age, sex, height, and weight
according to the Institute of Medicine Dietary Reference Intake
equations.
25
Given anecdotal evidence that suggests that
the majority of subjects with thalassemia participate in lim-
ited physical activity outside the home,EER was estimated
based on a sedentary lifestyle activity coefficient of 1.0. Percentage
of EER was calculated as %EER(kcal/EER)100.