SOF BMD data
Description
Dataset used in Chapter 7 of Regression Methods in Biostatistics (2nd edition), as distributed on the UCSF companion website. Study design: Longitudinal repeated-measures subset of SOF focused on bone mineral density outcomes. Primary article: Cummings and colleagues (1995), New England Journal of Medicine.
Usage
sof2
Format
A data frame with 42950 rows and 15 variables:
- id
- Participant identifier.
- visit
- Visit number (time point) in longitudinal follow-up.
- totbmd
- Total bone mineral density measurement.
- nbmd
- Bone mineral density at the analyzed skeletal site.
- vdate
- Date of follow-up visit.
- v2date
- Date of second follow-up visit.
- bmi
- Body mass index (kg/m^2).
- n_iadl
- Count of limitations in instrumental activities of daily living.
- age
- Age or age category at baseline (as coded in source data).
- meno_age
- Age at menopause (years).
- del_totbmd
- Change in total bone mineral density from baseline.
- base_totbmd
- Baseline total bone mineral density.
- meno_ov_52
- Indicator for menopause after age 52 years.
- visit_spl1
- First spline basis term for visit/time in longitudinal models.
- visit_spl2
- Second spline basis term for visit/time in longitudinal models.