homocyst {senstrat}

Homocysteine levels in daily smokers and never smokers.

Description

Data from NHANES 2005-2006 concerning homocysteine levels in daily smokers (z=1) and never smokers (z=0), aged 20 and older. Daily smokers smoked every day for the last 30 days, smoking an average of at least 10 cigarettes per day. Never smokers smoked fewer than 100 cigarettes in their lives, do not smoke now, and had no tobacco use in the previous 5 days.

Usage

data("homocyst")

Format

A data frame with 2475 observations on the following 10 variables.

SEQN

2005-2006 NHANES ID number.

homocysteine

Homocysteine level, umol/L. Based on LBXHCY.

z

z=1 for a daily smoker, z=0 for a never smoker. Based on SMQ020, SMQ040, SMD641, SMD650, SMQ680.

stf

A factor for strata indicating female, age, education, BMI and poverty.

st

Numeric strata indicating female, age, education, BMI and poverty.

female

1=female, 0=male. Based on RIAGENDR

age3

Three age categories, 20-39, 40-50, >=60. Based on RIDAGEYR.

ed3

Three education categories, <High School, High School, at least some College. Based on DMDEDUC2.

bmi3

Three of the body-mass-index, BMI, <30, [30,35), >= 35. Based on BMXBMI.

pov2

TRUE=income at least twice the poverty level, FALSE otherwise.

Details

Bazzano et al. (2003) noted higher homocysteine levels in smokers than in nonsmokers. See also Pimentel et al. (2016) for a related analysis. The example below is from Rosenbaum (2017).

Source

NHANES, the US National Health and Nutrition Examination Survey, 2005-2006.

References

Bazzano, L. A., He, J., Muntner, P., Vupputuri, S. and Whelton, P. K. (2003) Relationship between cigarette smoking and novel risk factors for cardiovascular disease in the United States. Annals of Internal Medicine, 138, 891-897.

Pimentel, S. D., Small, D. S. and Rosenbaum, P. R. (2016) Constructed second control groups and attenuation of unmeasured biases. Journal of the American Statistical Association, 111, 1157-1167.

Rosenbaum, P. R. (2017) Sensitivity analysis for stratified comparisons in an observational study of the effect of smoking on homocysteine levels. Manuscript.

Examples

data(homocyst)
#Homocysteine levels for daily smokers and nonsmokers.
boxplot(log(homocyst$homocysteine)~homocyst$z)