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Text File | 1994-08-22 | 19KB | 385 lines

Analysis of Anthropometric Data Using Epi Info Version 6 ║║║║║║║║ ║║║║║║║║║║ ║║║ ║║║║║║║║║║ ║║║ ║║║ ║║║║║║║║║ ║║║ ║║║ ║║║░░░░░░ ║║║░░░░║║║░ ║║║░ ║║║░░░░║║║░ ║║║║ ║║║░ ░░║║║░░░░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║║║ ║║║░ ║║║░ ║║║░ ║║║░ ║║║║║║║║ ║║║║║║║║║║░ ║║║░ ║║║║║║║║║║░ ║║║░║║ ║║║░ ║║║░ ║║║║║║║║║║░ ║║║░░░░░░ ║║║░░░░░░░░ ║║║░ ║║║░░░░║║║░ ║║║░ ║║║║║░ ║║║░ ║║║░░░░║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║║░ ║║║░ ║║║░ ║║║░ ║║║║║║║║ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ║║║░ ░░░░░░░░ ░░░ ░░░ ░░░ ░░░ ░░░ ░░░ ░░░ ░░░ ░░░ Version 2.0, 19/May/1994 By ------------------------------------------------------------------ | Kevin M. Sullivan, PhD, MPH, MHA | | Assistant Professor ----------------------| | Emory University School of Public Health | Home address: | | 1599 Clifton Road, NE | 1806 Coventry Road | | Atlanta GA 30329 | Decatur, GA 30030 | | USA | USA | | Phone: 404-727-4552 or 404-727-5417 | Phone: 404-377-9405 | | Fax: 404-727-4590 or 404-727-8737 ----------------------| | e-mail: kevin@emory.emry.sph.emory.edu or kevin@emory.em.cdc.gov | ------------------------------------------------------------------ INTRODUCTION EpiAnth was developed to provide standard analyses of anthropometry data within Epi Info. EpiAnth is a program file that can be "RUN" in ANALYSIS. Additional information on the calculation and analysis of anthropometric data can be found in Chapter 23 of the Epi Info Version 6 manual. This documentation on EpiAnth assumes that the user is familiar with Epi Info. EpiAnth FILES The following files are distributed with Epi Info within the Anthropometry module that are specific to EpiAnth: EpiAnth.PGM The program file EpiAnth.TXT This documentation ECENTILE.RPT Report file, centile distribution EFLAG1.RPT Report file, record flag dist. EFLAG2.RPT Report file, record flag dist. ELOWHAWH.RPT Report file, low W/H & H/A dist. EPREV.RPT Report file, prev. of low anthropometry EZSCORE.RPT Report file, Z-score distribution NORMAL.REZ Reference population distribution It is recommended that these files be located into the same directory as Epi Info (usually the subdirectory name is EPI6). REQUIREMENTS TO USE EpiAnth EpiAnth assumes that you have an Epi Info data file in which the anthropometric indices were calculated in ENTER. EpiAnth will also work with files created with EpiNut. The following fields, codes, and field types must in the the data file: Field Label Field Names and Codes Field Type ----- -------------------------------------------- ----------------- SEX Sex - coded as M/F, m/f, or 1/2 numeric/character AGE Age in months numeric The following field names must be used for the fields you wish to analyze: Field Label Field Names Field Typ ----- -------------------------------------------- ------------------ HAP Height-for-Age Percentile numeric HAZ Height-for-Age Z-score numeric HAM Height-for-Age Percent-of-Median numeric WAP Weight-for-Age Percentile numeric WAZ Weight-for-Age Z-score numeric WAM Weight-for-Age Percent-of-Median numeric WHP Weight-for-Height Percentile numeric WHZ Weight-for-Height Z-score numeric WHM Weight-for-Height Percent-of-Median numeric FLAG Record flag (more information on this below) numeric/character EpiAnth can be used with dBase files that have been processed with the program ANTHRO (a program for batch processing of dBase files) as long as the dBase file has the field names and definitions as listed above. HOW TO USE EpiAnth Once in ANALYSIS, enter RUN EpiAnth After two introductory screens on EpiAnth, the Main Menu will appear. The types of analysis EpiAnth can perform are shown in the Main Menu: ** M a i n M e n u ** Enter the type of analysis you would like to perform Z-scores Centiles Prevalence Other ═════════ ═════════ ══════════════════ ═════════ 1 Ht/Age 4 Ht/Age 7 Ht/Age 11 Flags 2 Wt/Ht 5 Wt/Ht 8 Wt/Ht 3 Wt/Age 6 Wt/Age 9 Ht/Age & Wt/Ht 10 Wt/Age Epi Info commands Other commands ══════════════════════ ═══════════════════════════════ BROWSE DOS QUIT 90 Define extremes as MISSING READ ROUTE UPDATE 91 Enter an Epi Info command 92 Read Documentation 99 Return to Analysis The Main Menu is divided into different sections: Z-scores, Centiles, Prevalence, Other, Epi Info commands, and Other commands. First, you need to have a file containing anthropometry information. If you do not have such a file, you can use the example file NUTRI.REC. The next thing that should be done when using the EpiAnth program is to run option 90 which recodes extreme or missing anthropometric values as missing. Each of the menu items is described next. Z-SCORES Z-score distributions are provided for Ht/Age, Wt/Ht, and Wt/Age. The Z-score, a continuous variable, is categorized into 19 different groups. The number and percent of children in each of the categories is provided, and distribution of the reference population is also listed for comparison purposes (see example below). In addition, summary statistics on the Z-score are provided. ----------------------------------------------------------------------------- Height/Age Z-score distribution 05/19/94 10:57:31 AM ____Z-score_________No.____Percent_______Reference_____ -6.00 to -5.0 0 0.0 - -4.99 to -4.5 0 0.0 - -4.49 to -4.0 0 0.0 - -3.99 to -3.5 0 0.0 - -3.49 to -3.0 5 5.2 0.1 -2.99 to -2.5 11 11.3 0.5 -2.49 to -2.0 11 11.3 1.7 -1.99 to -1.5 17 17.5 4.4 -1.49 to -1.0 13 13.4 9.2 -0.99 to -0.5 21 21.6 15.0 -0.49 to 0.0 6 6.2 19.1 0.01 to 0.5 8 8.2 19.1 0.51 to 1.0 2 2.1 15.0 1.01 to 1.5 1 1.0 9.2 1.51 to 2.0 0 0.0 4.4 2.01 to 2.5 2 2.1 1.7 2.51 to 3.0 0 0.0 0.5 3.01 to 3.5 0 0.0 0.1 3.51 to 6.0 0 0.0 - ** Total 97 100.0 100.0 ** Total Sum Mean Variance Std Dev Std Err 97 -125 -1.293 1.336 1.156 0.117 Minimum 25%ile Median 75%ile Maximum Mode -3.430 -2.070 -1.300 -0.700 2.460 -1.720 Student's "t", testing whether mean differs from zero. T statistic = 11.022, df = 97 p-value = 0.00000 ----------------------------------------------------------------------------- On the next screen you have the choice of producing a graph of the Z-score distribution comparing the study population with the reference. ---------------------------------------------------------------- | Would you like a Z-score graph 1 = yes, 2 = no* | | (*default response) | ---------------------------------------------------------------- The graph requires the computer to have graphics capability (e.g., a CGA/EGA/VGA/Hercules graphics board and monitor). Two curves are presented: one for the study population and the other for the reference population. The reference population curve is generally the smoother looking curve on the right side of the graph. After graphing the Z-scores, you will need to reread the datafile. (Note: to make the Z-score distribution several temporary files are created. Once a new file is READ, the program is unable to return to the original data file. In addition, all SELECT statements are cleared when a datafile is READ.) Z-score distributions can also be performed for Wt/Ht and Wt/Age. CENTILES Centile distributions can beprovided for Ht/Age, Wt/Ht, and Wt/Age. Each percentile value is categorized into 10 percentiles groupings, e.g., 0-9.99, 10.9-19.99, etc. The number and percent and children is provided, as is the percent of the reference population. An example of the output from the centile distribution option is shown below: ----------------------------------------------------------------------------- Height/Age Centile distribution 05/19/94 10:57:44 AM -------------------------------------------------------------------------- | Centiles | | 0.0- 10.0- 20.0- 30.0- 40.0- 50.0- 60.0- 70.0- 80.0- 90.0- | Total | 9.9 19.9 29.9 39.9 49.9 59.9 69.9 79.9 89.9 100 | ------+------------------------------------------------------------+------ no. | 51 14 11 6 2 3 5 2 1 2 | 97 % | 52.6 14.4 11.3 6.2 2.1 3.1 5.2 2.1 1.0 2.1 | 100.0 -------------------------------------------------------------------------- Reference Population -------------------------------------------------------------------------- %| 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 | 100.0 -------------------------------------------------------------------------- In addition, you have the option to display the data as a bar chart. PREVALENCE The prevalence of low anthropometry by age group can be determined for Ht/Age, Wt/Ht, and Wt/Age. The cutoff value for low anthropometry can be in terms of a Z-score, centile, or percent of median (see below): ---------------------------------------------------------------- | Select the cut-point for prevalence of low anthropometry | | | | Z-scores Centiles Percent of Median | | -------- --------- -------------------- | | 1 < -1 4 < 10th 7 < 95 11 < 75 | | 2 < -2 5 < 5th 8 < 90 12 < 70 | | 3 < -3 6 < 3rd 9 < 85 13 < 65 | | 10 < 80 14 < 60 | |------------------------Other Options---------------------------| | 98 Exit to Analysis 99 Exit to DOS | ---------------------------------------------------------------- In this example, option 2 (<-2 Z-score units) is selected, and the output is shown on the next page. Prevalence of low Height/Age 05/19/94 10:57:57 AM (<-2 SD: Percent of reference population less than cutpoint = 2.3%) |Age Group | Males | Females | Males & Females | |(months) | Low Total % | Low Total % | Low Total % | |----------+-------------------+-------------------+-------------------| | <6 | 0 6 0.0 | 0 4 0.0 | 0 10 0.0 | | 6-11.99 | 0 6 0.0 | 0 3 0.0 | 0 9 0.0 | | 12-23.99 | 1 6 16.7 | 2 10 20.0 | 3 16 18.8 | | 24-35.99 | 0 7 0.0 | 4 13 30.8 | 4 20 20.0 | | 36-47.99 | 6 10 60.0 | 3 10 30.0 | 9 20 45.0 | | 48-59.99 | 6 15 40.0 | 5 7 71.4 | 11 22 50.0 | | 60+ | 0 0 0.0 | 0 0 0.0 | 0 0 0.0 | |----------+-------------------+-------------------+-------------------| | Total | 13 50 26.0 | 14 47 29.8 | 27 97 27.8 | The output divides the population into males and females and by age group. The number and percent of children with low anthropometry for each age-sex group is provided, and a combined sex group. For cells with zero children, an error message will be placed on the screen (but will not appear in printed tables or when ROUTEd to a file): Division by zero, result set to 0 Press the <Esc> key and the program will continue. Another prevalence table is presented for option 9 from the main menu. This option presents the combined low anthropometry (<-2 Z-score) for both Ht/Age and Wt/Ht: Table of Low Height/Age and Low Weight/Height 05/19/94 10:58:21 AM Low Height/Age Yes No Total ------------------------- Low Yes no.| 14 | 21 | 35 Weight/ % | 14.6 | 21.9 | 36.5 Height |------------+------------| No no.| 13 | 48 | 61 % | 13.5 | 50.0 | 63.5 -------------------------+------------ Total no. 27 69 | 96 % 28.1 71.9 | 100.0 (Low Height/Age and low Weight/Height defined as < -2 SD) OTHER FLAGS are used to identify records with missing data or data that is likely to be incorrect. See the Epi Info documentation for a more detailed description of FLAGS. Option 11 of the main menu provides a description of the distribution of the FLAGS, and the following two screens are presented: Distribution of Record Flag Values Flag Index Flagged ____Records___ Code H/A W/H W/A No. % Notes ------------------------------------------------------------- 0 . . . 96 96.0 No indices flagged 1 Y . . 1 1.0 H/A flagged 2 . Y . 0 0.0 W/H flagged 3 Y Y . 1 1.0 H/A & W/H flagged 4 . . Y 0 0.0 W/A flagged 5 Y . Y 1 1.0 H/A & W/A flagged 6 . Y Y 1 1.0 W/H & W/A flagged 7 Y Y Y 0 0.0 All 3 indices flagged ------------------------------------------------------------ Total 100 100.0 Distribution of Record Flag Values Records Flagged Index Flagged No. % -------------------------------------- H/A 3 3.0 W/H 2 2.0 W/A 2 2.0 -------------------------------------- Total* 4 4.0 *The total number of records with an index flagged. The column may not add up to the total because a record can have multiple indices flagged. EPI INFO COMMANDS From the Main Menu, the following Epi Info commands can be entered at the prompt: BROWSE, DOS, QUIT, READ, ROUTE, SELECT, and UPDATE. These commands perform the same as usual in ANALYSIS with the following exceptions: BROWSE cannot specify variables to BROWSE READ cannot specify a file to read; however, after entering the READ command, the .REC file "pick list" will be presented on the screen and you will be able to select the file you want to READ ROUTE you can ROUTE to the SCREEN or to the PRINTER but not to a file. SELECT can only be used to clear a SELECT statement UPDATE similar to BROWSE, you cannot specify variables to UPDATE Note, however, that using Main Menu option 91 you can enter any Epi Info command. For example, if you want to BROWSE only certain fields, you could select option 91 and enter, for example, BROWSE WEIGHT HEIGHT. Also note that the function keys at the bottom of the screen can be used: F1-Help F2-Commands F3-Variables F4-Browse F5-Printer on F9-DOS F10-Quit OTHER COMMANDS The Other Commands in the Main Menu are: 90 Define extremes as MISSING - to change missing or extreme anthropometric values to missing (i.e., ".") values. This is an extremely important option that should be run first before performing any analyses 91 Enter an Epi Info command - as described above, this option allows any Epi Info command to be entered without leaving the EpiAnth program. 92 Read Documentation - TYPEs this file (EpiAnth.TXT) to the output window of ANALYSIS 99 Return to ANALYSIS - exits the EpiAnth program SUMMARY Please feel free to distribute or modify Epi-Anth. If you make modifications please remove any references to the name Epi-Anth. Error handling by Epi-Anth is limited by the programming facilities provided within ANALYSIS. All programs and report files were developed and tested using Epi Info versions 6.0. A suggested reference for EpiAnth is: Sullivan KM. EpiAanth Version 2.0: Analysis of Anthropometry Data Using Epi Info Version 6. Atlanta, Georgia, USA, 1994. ACKNOWLEDGEMENTS Some programming ideas were from Denis Coulombier and Robert Fagan, CDC. Press <Enter> to return to the Main Menu