In this exercise you will learn to take the variables from
either:
- an existing SPSS Windows (.sav) file
- an Epi-Info .mdb file
...and to calculate z-score values using
Epi-Info Nutrition. Then you will learn how to export the new z-score information back in
the existing file for analysis.
Child growth
standards used to calculate z-scores in the following exercise with Epi Info
The exercise uses calculations from the CDC 2000
reference. Since then, in 2006, the World Health Organization (WHO) has
released new child growth standards based on measurements of children receiving
nourishment in environments consistent with current nutritional recommendations,
considering such care to be standard practice. Measurements
were made from children taken from six previous samples selected from across the globe. Importantly, breast-feeding was considered
normative behavior, in contrast to previous standards developed from a single North
American sample of “artificially-fed” children. These new growth charts are
intended to show how children are expected to grow under ideal conditions. Differences present in the new standards regard
estimates of stunting (shown to be increased throughout childhood), and estimates of
underweight and wasting (shown to be increased in infancy and less frequent
thereafter). New indicators are also included to monitor trends in overweight and
obesity.** |
Calculating anthropometric variables (Z scores) from an
existing SPSS Windows (.sav) file
- Open the seasia0.sav
file which contains some data.
- Select File, Save as with a new name (seasia2)
and a new file type [DbaseIV (.dbf)] (the save in box at the top is
where you are saving the file. For easy access save in desktop.)
- Go to Analyze Data in Epi-Info Analysis, select Analysis
Commands, Data, Read (a new box will appear)
- Select data format DbaseIV and browse under Data Source to
find seasia2, Click OK
- From the left-hand sidebar: Select Analysis Commands,
Data, Write (Export) (a new box will appear)
- Name the file seasia3 under File Name and
name the table anthro under Data Table
- Click OK (the new .mdb file has been saved to the
same location as seasia2)
We will now move to Epi Info Nutrition.
- Open Epi Info, select Programs, Nutrition.
Select File, External Data, Import. Open seasia3. Select table
anthro
- Name the new file seasia4 under Output Database
and name the table anthro2 under Output Table.
- Select CDC 2000 reference
- Now we must link the variables:
- Under Input Field select SEX (This must be in the format 1= male 2= female),
under Field Type select Sex, click Link.
- Under Input Field select HT, under Field Type
select Height and click Link. Select cm.
- Under Input Field select MUAC, under Field Type
select Arm Circum and click Link. Select cm.
- Under Input Field select WT, under Field Type
select Weight and click Link. Select Kilos.
- Under Input Field select CHAGE, under Field Type
select Age and click Link. Select Mos.
- Click process, yes [the file has been created (seasia4.mdb)
and is located in the same place as seasia3]
Exporting the new file (SEAsia4.mdb) for analysis in SPSS
Windows (this is the same process used above, in reverse)
- Go to Analyze Data in Epi-Info Analysis, select Analysis
Commands, Data, Read (a new box will appear)
- Browse under Data Source to find seasia4,
open and select table nutanthro2
- Click OK, a new box will appear- click OK again
- Select Analysis Commands, Data, Write (Export) (a
new box will appear)
- Select output format dBASE IV
- Name the file seasia5 under File Name and
name the table anthro3 under Data Table
- Click OK [the new .dbf file has been saved to the
Epi Info folder (C:/Epi Info)]
- Open SPSS. Select File, Open, Data. Select
files of type dBase (.dbf) and browse for seasia5
- Once opened, select File, Save As and name seasia6
You now have a new SPSS (.sav) file that includes
weight-for-height z scores, weight-for-age z scores, height-for-age z scores,
muac-for-height z scores, & muac-for-age z scores
** “ The WHO Multicentre Growth Reference Study (MGRS).” The WHO
Child Growth Standards. The World Health
Organization. 7 July 2006. http://www.who.int/childgrowth/mgrs/en/
