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Risk Factors Associated with Low Infant Birth Weight

Source: R/data.R
Birthwt.Rd

The Birthwt data contains 189 observations, 16 predictors, and an outcome, birthweight, available both as a continuous measure and a binary indicator for low birth weight.The data were collected at Baystate Medical Center, Springfield, Mass during 1986. This data frame is a reparameterization of the birthwt data frame from the MASS package.

Usage

Birthwt

Format

The Birthwt object is a list containing four elements (X, bwt, low, and group):

bwt

Birth weight in kilograms

low

Indicator of birth weight less than 2.5kg

group

Vector describing how the columns of X are grouped

X

A matrix with 189 observations (rows) and 16 predictor variables (columns).

The matrix X contains the following columns:

age1,age2,age3

Orthogonal polynomials of first, second, and third degree representing mother's age in years

lwt1,lwt2,lwt3

Orthogonal polynomials of first, second, and third degree representing mother's weight in pounds at last menstrual period

white,black

Indicator functions for mother's race; "other" is reference group

smoke

Smoking status during pregnancy

ptl1,ptl2m

Indicator functions for one or for two or more previous premature labors, respectively. No previous premature labors is the reference category.

ht

History of hypertension

ui

Presence of uterine irritability

ftv1,ftv2,ftv3m

Indicator functions for one, for two, or for three or more physician visits during the first trimester, respectively. No visits is the reference category.

Source

https://cran.r-project.org/package=MASS

References

  • Venables, W. N. and Ripley, B. D. (2002). Modern Applied Statistics with S. Fourth edition. Springer.

  • Hosmer, D.W. and Lemeshow, S. (1989) Applied Logistic Regression. New York: Wiley

See also

MASS::birthwt, grpreg()

Examples

data(Birthwt)
hist(Birthwt$bwt, xlab="Child's birth weight", main="")

table(Birthwt$low)
#> 
#>   0   1 
#> 130  59 
## See examples in ?birthwt (MASS package)
##   for more about the data set
## See examples in ?grpreg for use of this data set
##   with group penalized regression models