wgs: Calculate WHO Growth Reference z-score for given...
In nutriverse/zscorer: Child Anthropometry z-Score Calculator

Description Usage Arguments Details Value Examples

The first function, getWGSR(), is usually called by the addWGSR() function but could be used as a stand-alone calculator for getting z-score for a given anthropometric measurement.

getWGSR(sex, firstPart, secondPart, thirdPart = NA, index = NA, standing = NA)

addWGSR(
  data,
  sex,
  firstPart,
  secondPart,
  thirdPart = NA,
  index = NA,
  standing = NULL,
  output = paste(index, "z", sep = ""),
  digits = 2
)

sex

Name of variable specifying the sex of the subject. This must be coded as 1 = male and 2 = female. Give a quoted variable name as in (e.g.) "sex".

firstPart

Name of variable specifying:

Weight (kg) for BMI/A, W/A, W/H, or W/L
Head circumference (cm) for HC/A
Height (cm) for BMI/A for H/A
Length (cm) for L/A
MUAC (cm) for MUAC/A
Sub-scapular skinfold (mm) for SSF/A
Triceps skinfold (mm) for TSF/A

Give a quoted variable name as in (e.g.) "weight". Be careful with units (weight in kg; height, length, head circumference, and MUAC in cm, skinfolds in mm).

secondPart

Name of variable specifying:

Age (days) for H/A, HC/A, L/A, MUAC/A, SSF/A, or TSF/A
Height (cm) BMI/A or W/H
Length (cm) for W/L

Give a quoted variable name as in (e.g.) "age". Be careful with units (age in days; height and length in cm).

thirdPart

Name of variable specifying age (in days) for BMI/A. Give a quoted variable name as in (e.g.) "age". Be careful with units (age in days).

index

The index to be calculated and added to data. One of:

Index	Definition
`bfa`	BMI for age
`hca`	Head circumference for age
`hfa`	Height for age
`lfa`	Length for age
`mfa`	MUAC for age
`ssa`	Sub-scapular skinfold for age
`tsa`	Triceps skinfold for age
`wfa`	Weight for age
`wfh`	Weight for height
`wfl`	Weight for length

Give a quoted index name as in (e.g.) "wfh".

standing

Variable specifying how stature was measured. If NULL then age (for "hfa" or "lfa") or height rules (for "wfh" or "wfl") will be applied. This must be coded as 1 = Standing; 2 = Supine; 3 = Unknown. All other values will be recoded to 3 = Unknown. Give a quoted variable name as in (e.g.) "measured" or a single value (e.g. "measured = 1). If no value (or NULL) is specified then height and age rules will be applied.

data

A survey dataset as a data.frame object

output

The name of the column containing the specified index to be added to the dataset. This is an optional parameter. If you do not specify a value for output then the added column will take the name of the specified index with a "z" appended.

digits

The number of decimal places for output. Defaults to 2 d.p.

addWGSR() adds the WHO Growth Reference z-scores to a data frame of anthropometric data for weight, height or length, MUAC, head circumference, sub-scapular skinfold, triceps skinfold, and body mass index (BMI).

A data.frame of the survey dataset with the calculated z-scores added.

# Given a male child 10 months old with a weight of 5.7 kgs, height of 64.2
# cms, and MUAC of 125 mm:
#
# Calculate weight-for-height
getWGSR(sex = 1,
        firstPart = 5.7,
        secondPart = 64.2,
        index = "wfh",
        standing = 3)

# calculate weight-for-age
getWGSR(sex = 1,
        firstPart = 5.7,
        secondPart = 10,
        index = "wfa",
        standing = 3)

# calculate height-for-age
getWGSR(sex = 1,
        firstPart = 64.2,
        secondPart = 10,
        index = "hfa",
        standing = 3)

# Calculate MUAC-for-age z-score for a girl
getWGSR(sex = 1,
        firstPart = 20,
        secondPart = 62 * (365.25 / 12),
        index = "mfa")

# Calculate weight-for-height (wfh) for the anthro3 dataset
addWGSR(data = anthro3,
        sex = "sex",
        firstPart = "weight",
        secondPart = "height",
        index = "wfh")

# Calculate weight-for-age (wfa) for the anthro3 dataset
addWGSR(data = anthro3,
        sex = "sex",
        firstPart = "weight",
        secondPart = "age",
        index = "wfa")

# Calculate height-for-age (hfa) for the anthro3 dataset
addWGSR(data = anthro3,
        sex = "sex",
        firstPart = "height",
        secondPart = "age",
        index = "hfa")

# Calculate MUAC-for-age (mfa) for the anthro4 dataset

## Convert age in anthro4 from months to days
testData <- anthro4
testData$age <- testData$agemons * (365.25 / 12)

addWGSR(data = testData,
        sex = "sex",
        firstPart = "muac",
        secondPart = "age",
        index = "mfa")