getCohortWGS {zscorer}

Calculate z-scores for WHZ, HAZ, WAZ using the WHO Growth Reference (2006) for a cohort or sample of children.

Description

Calculate z-scores for WHZ, HAZ, WAZ using the WHO Growth Reference (2006) for a cohort or sample of children.

Usage

getCohortWGS(data, FUN = getWGS, sexObserved, firstPart, secondPart,
  index)

Arguments

data

Data frame containing the variables needed for calculation

FUN

Function to apply; default to getWGS()

sexObserved

Sex of child (1 = Male; 2 = Female)

firstPart

Weight (kg; for WHZ and WAZ) or height (cm; for HAZ)

secondPart

Age (months; for HAZ and WAZ) or height (cm; for WHZ)

index

One of "wfh", "hfa", "wfa" (specifies the required index)

Value

Numeric vector of z-scores of the anthropometric index selected

The function fails messily when secondPart is outside of the range given in the WGS reference (i.e. 45 to 120 cm for height and 0 to 60 months for age). It is up to you to check the ranges of your data.

The reference data for W/H assumes supine length is used for children with a standing height below 85cm

Heights should be specified in cm to the nearest mm (i.e. to 1 d.p.)

Ages should be specified in whole months

Weights should be specified in kg to available precision

The function requires reference data wgsData included in this package

Examples

  # apply getWGS to first child in sample data anthro1
  wazAll <- getCohortWGS(data = anthro1,
                         sexObserved = "sex",
                         firstPart = "weight",
                         secondPart = "age",
                         index = "wfa")
  wazAll

  hazAll <- getCohortWGS(data = anthro1,
                         sexObserved = "sex",
                         firstPart = "height",
                         secondPart = "age",
                         index = "hfa")
  hazAll

  whzAll <- getCohortWGS(data = anthro1,
                         sexObserved = "sex",
                         firstPart = "weight",
                         secondPart = "height",
                         index = "wfh")
  whzAll