F&N Bulletin Vol 23 No 1b - United Nations University

28
tion in public schools, at the same time as nutrition
education and physical activity programs to prevent
increasing obesity in private schools are apparently
called for.
The study also showed a decreasing Z score in
height-for-age and weight-for-age with age from 8
to 10 years in both public and private schools. This
trend was also reflected in the increasing prevalence
of stunting and underweight with age from 8 to 10
years, particularly in public schools. If this trend is real,
it may have important programmatic implications.
However, it may reflect, at least in part, the start of
puberty and the influence of ethnicity affecting the
significance of the differences from NCHS standards.
As Flegal [9] pointed out, no valid comparisons in
prevalence among age and sex groups may be made
using statistical approaches in defining nutritional
status, because variability among these groups may
be constrained by the assumptions built into the
cutoffs used. Thus, in contrast to public schoolchildren
where thinness (BMI less than the 5th percentile)
increased with age, thinness generally decreased with
age among private schoolchildren. There is a need
either to examine the reference standards for use in
Filipino preadolescent and adolescent children or to
validate the cutoff points used.
Private schoolchildren had a greater relative change
in height and weight Z scores from 8 to 10 years of
age than public schoolchildren, resulting in a larger
increase in BMI with age. The increase in BMI with
age has also been noted among American children
[8]. However, the increase should be interpreted with
caution because of limitations of BMI as a measure
of nutritional status in older schoolchildren due to
changing body composition and degree of maturity
with age and the influence of ethnicity.
There was an increasing prevalence of underweight
and stunting with age from 8 to 10 years, but a generally
decreasing prevalence of overweight, in spite of
the generally increasing BMI. However, further study
is needed to determine whether these trends and differences
are real and not due to reference standards
and cutoff points.
In order to compare weight-for-height index with
BMI in assessing wasting/thinness and overweight,
the same group of children was analyzed using both
the WHO indices [6] and those of Troiano et al. [7].
Children whose heights exceeded the limits of the
NCHS/WHO weight-for-height table were excluded
from the analysis. The results are shown in table 3 and
figure 2. For both sexes combined, the prevalence of
thinness, as defined by BMI less than the 5th percentile,
was three times higher than that of wasting, as defined
by weight-for-height < –2 SD in both public and
private schoolchildren. Although this may be explained
by the cutoffs used, perhaps the significance of thinness,
as defined by BMI, is different from that of
30
25
20
% 15
10
5
0
Public schoolchildren
Wasting
Thinness
Overweight
At risk of overweight
Overweight
FIG. 2. Comparison of under- and overnutrition among
schoolchildren according to type of school using weight-forheight
Z score and BMI-for-age
wasting, as defined by weight-for-height. Using the
cutoff of BMI above the 85th percentile to define “at
risk of overweight,” as suggested by WHO [6], gives a
prevalence of overweight from one to three times as
high as that obtained using weight-for-height Z scores.
On the other hand, the prevalence of overweight, as
defined by BMI at or above the 95th percentile, was in
close agreement with that defined by weight-for-age
Z scores. From our data it appears that the BMI range
from at or above the 85th percentile to less than the
95th percentile could better define “risk of overweight”
than the whole range of BMI at or above the 85th
percentile, as recommended by WHO [6], whereas
BMI at or above the 95th percentile could define
“overweight,” as suggested by Troiano et al. [7].
Although it is generally agreed that BMI-for-age provides
the better criterion for evaluating thinness and
overweight, because it is a continuous indicator that
can be calculated from childhood to adulthood, there is
a need for a clearer definition of under- and overnutrition
when using anthropometric cutoff points in
various indices. In addition, there is a need for more
complete reference standards, including greater heights
in weight-for-height reference tables and younger ages
in BMI-for-age tables.
Acknowledgments
Weight-for-height
Private schoolchildren
Wasting
Thinness
Overweight
At risk of overweight
Overweight
This study was supported by the International Life Sciences
Institute Southeast Asia (ILSI SEA) in Singapore,
with supplemental funding from the Food and Nutrition
Research Institute (FNRI), Department of Science
and Technology, Philippines.
We thank the staff of the Nutritional Monitoring
BMI
R. F. Florentino et al.