This example uses the demoadv dataset (download at Sample Code and Datasets). In this example, you will assess the association between systolic blood pressure (mean_spb) — the outcome variable — and calcium supplement use (anycalsup) — the exposure variable — after controlling for selected covariates in NHANES 2003-2004. These covariates include race/ethnicity (ridreth1), age (ridageyr), and body mass index (BMI) (bmxbmi).