The UK 1990 revised growth reference (Cole et al 2011) for birth length, weight
and head circumference, fitted by the LMS method and summarised by values of L,
M and S by sex from 23 to 42 weeks gestation.
Usage
data(ukwhopt)
Format
A data frame with 40 observations on the following 12 variables:
weeks
numeric vector
years
numeric vector
L.ht
numeric vector
M.ht
numeric vector
S.ht
numeric vector
L.wt
numeric vector
M.wt
numeric vector
S.wt
numeric vector
L.head
numeric vector
M.head
numeric vector
S.head
numeric vector
sex
two-level factor with level 1 male and level 2 female
Details
The growth reference is the birth section of the UK-WHO growth reference
(see Wright et al 2010).
The L, M and S values for each measurement correspond respectively to the Box-Cox power,
median and coefficient of variation of the distribution by age and sex
(Cole & Green 1992). The short names for each measurement (see LMS2z)
are as follows: height (ht), weight (wt) and head circumference (head).
Age is measured in weeks gestation and years post-term,
where 0 years corresponds to 40 weeks gestation.
Cole TJ, Green PJ. Smoothing reference centile curves: the LMS method and
penalized likelihood. Stat Med 1992;11:1305-19.
Cole TJ, Williams AF, Wright CM, et al. Revised birth centiles for weight,
length and head circumference in the UK-WHO growth charts. Ann Hum Biol
2011;38:7-11.
Wright CM, Williams AF, Elliman D, et al. Using the new UK-WHO growth charts. BMJ 2010;-340:c1140.
Examples
data(ukwhopt)
## calculate median birth weight in girls from 23 to 42 weeks gestation
LMS2z(x = (23:42-40) * 7 / 365.25, y = 0, sex = 2, measure = 'wt', ref = 'ukwhopt', toz = FALSE)