Cross-sectional Data from the New Zealand Population
A cross-sectional data set of a workforce company, plus another health survey, in New Zealand during the 1990s,
data(xs.nz)
A data frame with 10529 observations on the following 58 variables.
For binary variables, a "1"
or TRUE
means yes
,
and "0"
or FALSE
means no
.
Also, "D"
means don't know,
and "-"
means not applicable.
The pregnancy questions were administered to women only.
regnum
a numeric vector, a unique registration number. This differs from their original registration number, and the rows are sorted by their new registration number.
study1
a logical vector, Study 1 (workforce) or Study 2?
age
a numeric vector, age in years.
sex
a factor with levels F
and M
.
pulse
a numeric vector, beats per minute.
sbp
a numeric vector, systolic blood pressure (mm Hg).
dbp
a numeric vector, diastolic blood pressure (mm Hg).
cholest
a numeric vector, cholesterol (mmol/L).
height
a numeric vector, in m.
weight
a numeric vector, in kg.
fh.heartdisease
a factor with levels 0
, 1
,
D
.
Has a family history of heart disease (heart attack, angina, or
had a heart bypass operation) within the immediate
family (brother, sister, father or mother, blood relatives only)?
Note that D
means: do not know.
fh.age
a factor, following from fh.heartdisease
,
if yes, how old was the family member when it happened (if
more than one family member, give the age of the
youngest person)?
fh.cancer
a factor with levels 0
, 1
,
D
.
Has a family history of cancer within the immediate
family (blood relatives only)?
Note that D
means: do not know.
heartattack
a numeric vector, have you ever been told by a doctor that you have had a heart attack ("coronary")?
stroke
a numeric vector, have you ever been told by a doctor that you have had a stroke?
diabetes
a numeric vector, have you ever been told by a doctor that you have had diabetes?
hypertension
a numeric vector, have you ever been told by a doctor that you have had high blood pressure (hypertension)?
highchol
a numeric vector, have you ever been told by a doctor that you have had high cholesterol?
asthma
a numeric vector, have you ever been told by a doctor that you have had asthma?
cancer
a numeric vector, have you ever been told by a doctor that you have had cancer?
acne
a numeric vector, have you ever received treatment from a doctor for acne (pimples)?
sunburn
a numeric vector, have you ever received treatment from a doctor for sunburn?
smokeever
a numeric vector, have you ever smoked tailor-made or roll-you-own cigarettes once a week or more?
smokenow
a numeric vector, do you smoke tailor-made or roll-you-own cigarettes now?
smokeagequit
a factor,
if no to smokenow
, how old were you when
you stopped smoking?
smokeyears
a numeric vector,
if yes to smokeever
, for how many years altogether
have you smoked tailor-made or roll-you-own cigarettes?
drinkmonth
a numeric vector, do you drink alcohol once a month or more?
drinkfreqweek
a numeric vector,
if yes to drinkmonth
, about how often do you
drink alcohol (days per week)?
Note: 0.25 is once a month,
0.5 is once every two weeks,
1 is once a week,
2.5 is 2-3 days a week,
4.5 is 4-5 days a week,
6.5 is 6-7 days a week.
Further note: 1 can, small bottle or handle of beer or home brew = 1 drink, 1 quart bottle of beer = 2 drinks, 1 jug of beer = 3 drinks, 1 flagon/peter of beer = 6 drinks, 1 glass of wine, sherry = 1 drink, 1 bottle of wine = 6 drinks, 1 double nip of spirits = 1 drink.
drinkweek
a numeric vector,
how many drinks per week, on average.
This is the average daily amount of drinks multiplied
by the frequency of drinking per week.
See drinkfreqweek
on what constitutes a 'drink'.
drinkmaxday
a numeric vector, in the last three months, what is the largest number of drinks that you had on any one day? Warning: some values are considered unrealistically excessive.
pregnant
a factor, have you ever been pregnant for more than 5 months?
pregfirst
a factor, if
yes to pregnant
, how old were you when your first
baby was born (or you had a miscarriage after 5 months)?
preglast
a factor, how old were you when your last baby was born (or you had a miscarriage after 5 months)?
babies
numeric, how many babies have you given birth to?
moody
a numeric vector, does your mood often go up or down?
miserable
a numeric vector, do you ever feel 'just miserable' for no reason?
hurt
a numeric vector, are your feelings easily hurt?
fedup
a numeric vector, do you often feel 'fed up'?
nervous
a numeric vector, would you call yourself a nervous person?
worrier
a numeric vector, are you a worrier?
worry
a numeric vector, do you worry about awful things that might happen?
tense
a numeric vector, would you call yourself tense or 'highly strung'?
embarrassed
a numeric vector, do you worry too long after an embarrassing experience?
nerves
a numeric vector, do you suffer from 'nerves'?
nofriend
a numeric vector,
do you have a friend or family member that you
can talk to about problems or worries that you may have?
The value 1 effectively means "no"
,
i.e., s/he has no friend or friends.
depressed
a numeric vector, in your lifetime, have you ever had two weeks or more when nearly every day you felt sad or depressed?
exervig
a numeric vector, how many hours per week would you do any vigorous activity or exercise either at work or away from work that makes you breathe hard and sweat? Values here ought be be less than 168.
exermod
a numeric vector, how many hours per week would you do any moderate activity or exercise such as brisk walking, cycling or mowing the lawn? Values here ought be be less than 168.
feethour
a numeric vector, on an average work day, how long would you spend on your feet, either standing or moving about?
ethnicity
a factor with 4 levels,
what ethnic group do you belong to?
European
= European (NZ European or British or other European),
Maori
= Maori,
Polynesian
= Pacific Island Polynesian,
Other
= Other (Chinese, Indian, Other).
sleep
a numeric vector, how many hours do you usually sleep each night?
snore
a factor with levels 0
, 1
,
D
.
Do you usually snore?
Note that D
means: do not know.
cat
a numeric vector, do you have a household pet cat?
dog
a numeric vector, do you have a household pet dog?
hand
a factor with levels
right
= right,
left
= left,
both
= either.
Are you right-handed,
left-handed,
or no preference for left or right?
numhouse
an ordered factor with 4 levels:
1
= 1,
2
= 2,
3
= 3,
4+
= four or more;
how many people (including yourself) usually live in your house?
marital
a factor with 4 levels:
single
= single,
married
= married or living with a partner,
separated
= separated or divorced,
widowed
= widowed.
educ
an ordered factor with 4 levels:
primary
= Primary school,
secondary
= High school/secondary school,
polytechnic
= Polytechnic or similar,
university
= University.
What was the highest level of education you received?
The data frame is a subset of the entire data set which was collected from a confidential self-administered questionnaire administered in a large New Zealand workforce observational study conducted during 1992–3. The data were augmented by a second study consisting of retirees. The data can be considered a reasonable representation of the white male New Zealand population in the early 1990s. There were physical, lifestyle and psychological variables that were measured. The psychological variables were headed "Questions about your feelings".
Although some data cleaning was performed and logic checks conducted, anomalies remain. Some variables, of course, are subject to a lot of measurement error and bias. It is conceivable that some participants had poor reading skills!
More variables may be added in the future and these may
be placed in any column position. Therefore references
such as xs.nz[, 12]
are dangerous.
Also, variable names may change in the future as well as
their format or internal structure,
e.g., factor
versus numeric
.
More error checking are needed for the pregnancy and smoking variables.
Originally,
Clinical Trials Research Unit, University of Auckland, New Zealand,
http://www.ctru.auckland.ac.nz
.
Originally much of the error checking and formatting was
performed by Stephen Vander Hoorn.
Lately (2014), more changes and error checks were made to the
data by James T. Gray.
MacMahon, S., Norton, R., Jackson, R., Mackie, M. J., Cheng, A., Vander Hoorn, S., Milne, A., McCulloch, A. (1995). Fletcher Challenge-University of Auckland Heart & Health Study: design and baseline findings. New Zealand Medical Journal, 108, 499–502.
data(xs.nz) summary(xs.nz)
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