betaplasma {CAMAN}

Determinants of Beta-Carotene Levels

Description

Observational studies have suggested that low dietary intake or low plasma concentrations of retinol, beta-carotene, or other carotenoids might be associated with increased risk of developing certain types of cancer. However, relatively few studies have investigated the determinants of plasma concentrations of these micronutrients. Nierenberg et al. designed a cross-sectional study to investigate the relationship between personal characteristics and dietary factors, and plasma concentrations of retinol, beta-carotene and other carotenoids. Study subjects (N = 315) were patients who had an elective surgical procedure during a three-year period to biopsy or remove a lesion of the lung, colon, breast, skin, ovary or uterus that was found to be non-cancerous.

Usage

data("betaplasma")

Format

datafile contains 315 observations on 15 variables. This data set can be used to demonstrate multiple regression, transformations, categorical variables, outliers, pooled tests of significance and model building strategies.

Variable Names in order from left to right:

item

participant id

age

Age (years)

sex

Sex, Factor with 2 levels (M=Male, F=Female).

smokestat

Smoking status, Factor with 3 levels (Never, Former, Current Smoker)

bmi

body mass index (weight/(height^2))

vituse

Vitamin Use, Factor with 3 levels (Yes (fairly often), Yes (not often), No)

calories

Number of calories consumed per day.

fat

Grams of fat consumed per day.

fiber

Grams of fiber consumed per day.

alcohol

Number of alcoholic drinks consumed per week.

chol

Cholesterol consumed (mg per day).

betadiet

Dietary beta-carotene consumed (mcg per day).

retdiet

Dietary retinol consumed (mcg per day)

betacaro

Plasma beta-carotene (ng/ml)

retplasma

Plasma Retinol (ng/ml)

References

Schlattmann, P.(2009) Medical Applications of Finite Mixture Models. Berlin: Springer.

These data have not been published yet but a related reference is

Nierenberg DW, Stukel TA, Baron JA, Dain BJ, Greenberg ER (1989) “Determinants of plasma levels of beta-carotene and retinol.” American Journal of Epidemiology, 130, 511–521.

The use of the data is kindly permitted Dr. Therese Stukel, Dartmouth Hitchcock Medical Center, USA

The data can also be found at StatLib: http://lib.stat.cmu.edu/index.php

Examples

data(betaplasma)
beta4 <- mixcov(dep="betacaro", fixed=c("chol","sex","bmi"), random="betadiet",
                data=betaplasma,k=4,family="gaussian")