Download and cache NHANES data locally — download_nhanes

Downloads all tables within the specified NHANES data groups for one or more survey years, merges them into a single data frame per year, and saves it as an RDS file. The resulting cache is used automatically by sample_covariates_nhanes().

Usage

download_nhanes_cache(
  groups = c("DEMO", "LAB", "EXAM"),
  years = "2017-2018",
  path = nhanes_default_cache_dir(),
  overwrite = FALSE,
  ...
)

Arguments

groups: character vector of NHANES data groups to download. Valid values: "DEMO" (Demographics), "LAB" (Laboratory), "EXAM" (Examination), "Q" (Questionnaire), "DIET" (Dietary). Defaults to c("DEMO", "LAB", "EXAM").
years: character vector of NHANES survey cycles, e.g. c("2015-2016", "2017-2018"). Defaults to "2017-2018".
path: directory where merged RDS files will be saved. Created automatically if it does not exist. Defaults to the package-level cache directory returned by nhanes_default_cache_dir().
overwrite: logical. If FALSE (default), a year that already has a merged RDS in path is skipped. Set to TRUE to re-download and overwrite.
...: additional arguments (currently unused)

Value

the path directory, invisibly.

Details

Each survey year is saved as a single file nhanes_<year>.rds (e.g. nhanes_2017-2018.rds) containing all variables from all downloaded tables, merged on the SEQN respondent sequence number. Tables with multiple rows per subject (e.g. dietary recall) are skipped automatically.

Requires the nhanesA package.