Previous 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.  We 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.
  
This datafile contains 315 observations on 14 variables.

Variable Names in order from left to right:

        AGE: Age (years)
        SEX: Sex (1=Male, 2=Female).
        SMOKSTAT: Smoking status (1=Never, 2=Former, 3=Current Smoker)
        QUETELET: Quetelet index (weight/(height^2)); values above 27 kg/m^2
                  (female) or 28 kg/m^2 (male) indicate obesity
        VITUSE: Vitamin Use (1=Yes, fairly often, 2=Yes, not often, 3=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.
        CHOLESTEROL: Cholesterol consumed (mg per day).
        BETADIET: Dietary beta-carotene consumed (mcg per day).
        RETDIET: Dietary retinol consumed (mcg per day)
        BETAPLASMA: Plasma beta-carotene (ng/ml)
        RETPLASMA: Plasma Retinol (ng/ml)