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

Nutritional status of urban primary schoolchildren. 1
Methods
The study was conducted in Manila, the most populous
of the 17 cities and municipalities in Metro
Manila. The subjects were schoolchildren 8 to 10 years
old who were selected by using a two-stage stratified
sampling design. Stratification was based on the type
of school (public or private) and the age and sex
of the children. The first stage involved selection of
the schools and the second selection of the subjects.
Fourteen schools were selected by systematic sampling,
with the private and public schools represented by
seven schools each. The schools were selected from a
list of all schools in Manila (69 public and 72 private)
that was provided by the Department of Education,
Culture and Sports. From each of the schools sampled,
a complete list of children was obtained, from
which subjects were then selected by stratified random
sampling.
Data collection
Interviews were conducted by trained interviewers
using pretested survey forms to solicit information on
dietary patterns through a three-day food record, activity
patterns, and nutrition knowledge, attitude, and
practice of both the child and the parents. Each subject
was weighed and measured by the standard techniques
described by Jelliffe [4]. Weight was measured to the
nearest 0.1 kg with a calibrated beam balance scale
(platform type). Standing height was measured to
the nearest 0.1 cm. with a “microtoise” attached to a
smooth straight wall.
The data collected were edited both in the field
and in the office, after which, master databases were
produced. Analysis of anthropometric data compared
actual height and weight data with the NCHS reference
standards using the ANTHRO Software of the Centers
for Disease Control, Atlanta, Ga., USA. Children were
considered underweight and stunted if their weight
and height Z scores were less than –2 SD of the NCHS
median for weight and height, respectively.
Since not all children could be analyzed for their
weight-for-height because the heights of 10% of the
children were beyond the limits of the NCHS Reference,
body mass index (BMI)-for-age was used as the
indicator to assess thinness and overweight. The table
of BMI proposed by Must et al. [5], which gives the
smoothed values for the 5th, 15th, 50th, 85th, and 95th
percentiles derived from NHANES I for 6 to 74 years
of age, was used as a reference. Thinness was defined
by BMI less than the 5th percentile, whereas those
with BMI values at or above the 85th percentile were
considered “at risk of overweight” as recommended by
WHO [6]. In addition, the 95th percentile was used to
determine overweight as defined by Troiano et al. [7].
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The data were processed using the Statistical Package
for Social Sciences (SPSS) to generate the required
output.
Indices used
The use of the NCHS/WHO weight-for-height index to
assess the nutritional status of the children was limited
by the fact that 122 (10%) of 1,208 subjects had heights
beyond the limits of the NCHS/WHO reference standard
for age. These included 34 public schoolchildren
(2 aged 8 years, 11 aged 9, and 21 aged 10) and 88
children in private schools (18 aged 8, 25 aged 9, and
45 aged 10). Hence, BMI-for-age was used instead for
the whole study population. In order to assess thinness
and overweight among the children, including those 8
years of age, the table proposed by Must et al. [5]
generated from NHANES I covering 6 years to adulthood
was used. Cutoff points proposed by WHO [6]
were applied to assess thinness (less than the 5th
percentile) and risk of overweight (at or above the 85th
percentile). An additional cutoff to define those more
markedly overweight (at or above the 95th percentile)
was also used, as suggested by Troiano et al. [7].
Results
Of the 1,288 schoolchildren in the original sample,
1,208 subjects completed all the phases of the survey,
which was more than the targeted sample size of 1,092.
The final sample size represented 1% of the estimated
total number of enrollees in the city of Manila for the
school year 1996–1997. Of this total, 642 came from
public schools and 566 came from private schools. In
both school categories, slightly more girls completed
the study than boys (50.5% vs. 49.5%).
Mean height, weight, and BMI
Children from private schools were on average taller
and heavier and had a higher BMI than those from
public schools (table 1). This observation was true for
both boys and girls and for all ages. Large differences
in height were particularly noted among the 8-yearold
children, with those in private schools, on average,
taller by as much as 7 cm. On the other hand, 10-yearold
private schoolchildren were heavier by almost 8 kg
among the boys and 6 kg among the girls. The same
was true for BMI: children from private schools had a
higher average BMI at all ages than those from public
schools, with the gap between the two increasing
with age. Both boys and girls from public and private
schools had increasing average BMI with increasing
age, except for public school boys whose average BMI
remained constant at 15.4 kg/m 2 .