Background and aims:
A worldwide increase in childhood overweight (OW) and obesity (OB) has been
reported. OB is an inflammatory state which affects iron metabolism and the
sensibility of the tests to detect iron deficiency (ID). Our aim was to
evaluate the adequacy of current ferritin cut-offs to define ID in children
with OW/OB.
Methods:
This cross-sectional study included 152 children (54% girls) aged (median
[Q1-Q3]) 11 (8-13) years with OW/OB. Complete blood count and iron
metabolism were evaluated. Low ferritin, transferrin saturation (TSat), and
anemia were defined by age- and sex-specific cut-offs recommended by
National Guidelines. Iron intake was assessed in a subgroup (n = 80) by a
24-hour dietary recall. Analyses were made according to pubertal development
and ferritin tertiles.
Results:
The overall prevalence of low ferritin, TSat, and anemia was 2.6%, 23.8%, and
5.2%, respectively. Among pre-pubertal children (n = 87), the frequency of
low TSat rose across ferritin tertiles (
P
< .05),
whereas it decreased among pubertal children (n = 65;
P
< .005). Cases of anemia among pre-pubertal children
were found in the highest ferritin tertile, whereas 4/6 anemia cases in
pubertal children were found in the lowest ferritin tertile (<39 µg/L).
Pubertal children within the lowest ferritin tertile + low TSat (n = 11)
showed lower hemoglobin (–9%;
P
< .005) and hematocrit
(–8%,
P
< .01) than those in the same tertile + normal
TSat (n = 16). The overall prevalence of children with
ferritin < 39 µg/L + low TSat was 9.2%.
Conclusions:
Higher ferritin cut-off values are required to define ID in children with
OW/OB. Such cut-off remains to be validated in larger, multi-ethnic cohorts
of children with OW/OB.