nh0506Homocysteine {DiPs}

Homocysteine and Smoking

Description

NHANES 2005-2006 data on smoking and homocysteine levels in adults.

Usage

data("nh0506Homocysteine")

Format

A data frame with 2759 observations on the following 11 variables.

X

Row number, 1 to 2759

SEQN

NHANES identification number

z

Smoking status, 1 = daily smoker, 0 = never smoker

female

1 = female, 0 = male

age

Age in years, >=20, capped at 85

black

1=black race, 0=other

education

Level of education

povertyr

Ratio of family income to the poverty level, capped at 5 times poverty

bmi

BMI or body-mass-index

cigsperday30

Cigarettes smoked per day, 0 for never smokers

cotinine

Blood cotinine level, a biomarker of recent exposure to tobacco

homocysteine

Level of homocysteine

Details

The following code constructed the data as used here. Attention is confined to adults, excluding children. Also, people who have smoked in the past, but do not now smoke daily, are excluded. A moderate number of individuals with missing povertyr, cotinine or homocysteine were excluded.

library(foreign)

DEMO<-read.xport("DEMO_D.XPT")

HCY<-read.xport("HCY_D.XPT")

SMQ<-read.xport("SMQ_D.XPT")

BMX<-read.xport("BMX_D.XPT")

COT<-read.xport("COT_D.XPT")

d<-merge(DEMO, HCY, by="SEQN", all.x=TRUE)

d<-merge(d, SMQ, by="SEQN", all.x=TRUE)

d<-merge(d, COT, by="SEQN", all.x=TRUE)

d<-merge(d, BMX, by="SEQN", all.x=TRUE)

rm(DEMO, HCY, SMQ, COT, BMX)

SEQN<-d$SEQN

age<-d$RIDAGEYR

race<-d$RIDRETH1

black<-1*(race==4)

hispanic<-1*((race==1)|(race==2))

female<-1*(d$RIAGENDR==2)

education<-d$DMDEDUC2

education[education>6]<-NA

povertyr<-d$INDFMPIR

homocysteine<-d$LBXHCY

bmi<-d$BMXBMI

cotinine<-d$LBXCOT

cigs100life<-d$SMQ020

cigs100life[cigs100life>3]<-NA

cigs100life<-(cigs100life==1)*1

smokenow<-1*(d$SMQ040<2.5)

smokenow[cigs100life==0]<-0

cigsdays30<-d$SMD641

cigsdays30[cigsdays30>32]<-NA

cigsdays30[smokenow==0]<-0

cigsperday30<-d$SMD650

cigsperday30[cigsperday30>100]<-NA

cigsperday30[smokenow==0]<-0

dailysmoker<-1*((cigs100life==1)&(cigsdays30==30)&(smokenow==1)&(cigsperday30>=10))

neversmoker<-1*((cigs100life==0)&(smokenow==0))

z<-dailysmoker

z[(neversmoker==0)&(dailysmoker==0)]<-(-999)

ds<-data.frame(SEQN, female, age, black, education, povertyr, bmi, homocysteine, cotinine, cigs100life, smokenow, cigsdays30, cigsperday30, dailysmoker, neversmoker, z)

use<-age>=20

ds1<-ds[use,]

use<-complete.cases(ds1)

ds1$z[ds1$z==-999]<-NA

ds2<-ds1[use&!is.na(ds1$z),]

rm(SEQN, female, age, black, hispanic, education, povertyr, homocysteine, cotinine, cigs100life, smokenow, cigsdays30, cigsperday30, dailysmoker, neversmoker, z, race, use, bmi)

ds2<-ds2[order(1-ds2$z),]

attach(ds2)

nh0505Homocysteine<-data.frame(SEQN, z, female, age, black, education, povertyr, bmi, cigsperday30, cotinine, homocysteine)

write.csv(nh0506Homocysteine, "nh0506Homocysteine.csv")

Source

From the NHANES web page, for NHANES 2005-2006.

References

US National Health and Nutrition Examination Survey, 2005-2006. From the US Center for Health Statistics.

Examples

data(nh0506Homocysteine)
summary(nh0506Homocysteine)