A data frame containing the age-dependent distribution of the D-score for children aged 0-5 years. The distribution is modelled after the LMS distribution (Cole & Green, 1992) or BCT model (Stasinopoulos & Rigby, 2022) and is equal for both boys and girls. The LMS/BCT values can be used to graph reference charts and to calculate age-conditional Z-scores, also known as DAZ.

builtin_references

Format

A data.frame with 265 rows and 17 variables:

NameLabel
popPopulation, either "dutch", "gcdg" or "phase1"
ageDecimal age in years
muM-curve, median D-score, P50
sigmaS-curve, spread expressed as coefficient of variation
nuL-curve, the lambda coefficient of the LMS/BCT model for skewness
tauKurtosis parameter in the BCT model
P3P3 percentile
P10P10 percentile
P25P25 percentile
P50P50 percentile
P75P75 percentile
P90P90 percentile
P97P97 percentile
SDM2-2SD centile
SDM1-1SD centile
SD00SD centile, median
SDP1+1SD centile
SDP2+2SD centile

Details

The "dutch" references were calculated from the SMOCC data, and cover age range 0-2.5 years (van Buuren, 2014). The "gcdg" references were calculated from the 15 cohorts of the GCDG-study, and cover age range 0-5 years (Weber, 2019). The "phase1" references were calculated from the GSED Phase 1 validation data (GSED-BGD, GSED-PAK, GSED-TZA) cover age range 2w-3.5 years. The age range 3.5-5 yrs is linearly extrapolated and are only indicative.

References

Cole TJ, Green PJ (1992). Smoothing reference centile curves: The LMS method and penalized likelihood. Statistics in Medicine, 11(10), 1305-1319.

Van Buuren S (2014). Growth charts of human development. Stat Methods Med Res, 23(4), 346-368. https://stefvanbuuren.name/publication/van-buuren-2014-gc/

Weber AM, Rubio-Codina M, Walker SP, van Buuren S, Eekhout I, Grantham-McGregor S, Caridad Araujo M, Chang SM, Fernald LCH, Hamadani JD, Hanlon A, Karam SM, Lozoff B, Ratsifandrihamanana L, Richter L, Black MM (2019). The D-score: a metric for interpreting the early development of infants and toddlers across global settings. BMJ Global Health, BMJ Global Health 4: e001724. https://gh.bmj.com/content/bmjgh/4/6/e001724.full.pdf

Stasinopoulos M, Rigby R (2022). gamlss.dist: Distributions for Generalized Additive Models for Location Scale and Shape, R package version 6.0-3, https://CRAN.R-project.org/package=gamlss.dist

See also

Examples

head(builtin_references)
#>     pop    age    mu  sigma     nu tau   P3   P10   P25   P50   P75   P90   P97
#> 1 dutch 0.0383  8.81 0.3126 1.3917  NA 3.15  5.07  6.91  8.81 10.57 12.07 13.49
#> 2 dutch 0.0575 10.59 0.2801 1.4418  NA 4.32  6.49  8.52 10.59 12.50 14.12 15.64
#> 3 dutch 0.0767 12.27 0.2526 1.4891  NA 5.61  7.96 10.10 12.27 14.28 15.97 17.56
#> 4 dutch 0.0958 13.87 0.2291 1.5331  NA 6.99  9.43 11.64 13.87 15.93 17.67 19.30
#> 5 dutch 0.1150 15.39 0.2089 1.5722  NA 8.42 10.89 13.13 15.39 17.47 19.23 20.89
#> 6 dutch 0.1342 16.83 0.1916 1.6049  NA 9.86 12.32 14.56 16.83 18.92 20.69 22.36
#>   SDM2  SDM1   SD0  SDP1  SDP2
#> 1 2.78  5.94  8.81 11.39 13.76
#> 2 3.88  7.46 10.59 13.38 15.94
#> 3 5.12  8.98 12.27 15.20 17.87
#> 4 6.47 10.48 13.87 16.87 19.61
#> 5 7.89 11.95 15.39 18.43 21.21
#> 6 9.33 13.39 16.83 19.88 22.68