mice (version 3.4.0)

selfreport: Self-reported and measured BMI

Description

Dataset containing height and weight data (measured, self-reported) from two studies.

Format

A data frame with 2060 rows and 15 variables:

src

Study, either krul or mgg (factor)

id

Person identification number

pop

Population, all NL (factor)

age

Age of respondent in years

sex

Sex of respondent (factor)

hm

Height measured (cm)

wm

Weight measured (kg)

hr

Height reported (cm)

wr

Weight reported (kg)

prg

Pregnancy (factor), all Not pregnant

edu

Educational level (factor)

etn

Ethnicity (factor)

web

Obtained through web survey (factor)

bm

BMI measured (kg/m2)

br

BMI reported (kg/m2)

Details

This dataset combines two datasets: krul data (Krul, 2010) (1257 persons) and the mgg data (Van Keulen 2011; Van der Klauw 2011) (803 persons). The krul dataset contains height and weight (both measures and self-reported) from 1257 Dutch adults, whereas the mgg dataset contains self-reported height and weight for 803 Dutch adults. Section 7.3 in Van Buuren (2012) shows how the missing measured data can be imputed in the mgg data, so corrected prevalence estimates can be calculated.

Examples

# NOT RUN {

md.pattern(selfreport[,c("age","sex","hm","hr","wm","wr")])

### FIMD Section 7.3.5 Application

bmi <- function(h,w){return(w/(h/100)^2)}
init <- mice(selfreport,maxit=0)
meth <- init$meth
meth["bm"] <- "~bmi(hm,wm)"
pred <- init$pred
pred[,c("src","id","web","bm","br")] <- 0
imp <- mice(selfreport, pred=pred, meth=meth, seed=66573, maxit=2, m=1)
## imp <- mice(selfreport, pred=pred, meth=meth, seed=66573, maxit=20, m=10)

### Like FIMD Figure 7.6 

cd <- complete(imp, 1)
xy <- xy.coords(cd$bm, cd$br-cd$bm)
plot(xy,col=mdc(2),xlab="Measured BMI",ylab="Reported - Measured BMI",
    xlim=c(17,45),ylim=c(-5,5), type="n",lwd=0.7)
polygon(x=c(30,20,30),y=c(0,10,10),col="grey95",border=NA) 
polygon(x=c(30,40,30),y=c(0,-10,-10),col="grey95",border=NA)
abline(0,0,lty=2,lwd=0.7)

idx <- cd$src=="krul"
xyc <- xy; xyc$x <- xy$x[idx]; xyc$y <- xy$y[idx]
xys <- xy; xys$x <- xy$x[!idx]; xys$y <- xy$y[!idx]
points(xyc,col=mdc(1), cex=0.7)
points(xys,col=mdc(2), cex=0.7)
lines(lowess(xyc),col=mdc(4),lwd=2)
lines(lowess(xys),col=mdc(5),lwd=2)
text(1:4,x=c(40,28,20,32),y=c(4,4,-4,-4),cex=3)
box(lwd=1)


# }