Waist-to-height ratio (WHtR) — calculate_waist_height

This function calculates the Waist-to-Height Ratio (WHtR) by dividing the waist circumference by the height of the respondent.

Usage

calculate_waist_height_ratio(hwm_11cm, hwm_14cx)

Arguments

hwm_11cm: numeric A numeric representing the height of the respondent in centimeters.
hwm_14cx: numeric A numeric representing the waist circumference of the respondent in centimeters.

Value

numeric The WHtR. If inputs are invalid or out of bounds, the function returns a tagged NA.

Details

This function calculates the Waist-to-Height Ratio (WHtR), an indicator of central obesity.

     **Missing Data Codes:**
     - `hwm_11cm`:
       - `999.96`: Valid skip. Handled as `haven::tagged_na("a")`.
       - `999.97-999.99`: Don't know, refusal, or not stated. Handled as `haven::tagged_na("b")`.
     - `hwm_14cx`:
       - `999.6`: Valid skip. Handled as `haven::tagged_na("a")`.
       - `999.7-999.9`: Don't know, refusal, or not stated. Handled as `haven::tagged_na("b")`.

Examples

# Scalar usage: Single respondent
# Example 1: Calculate WHtR for a respondent with height = 170 cm and waist circumference = 85 cm.
calculate_waist_height_ratio(hwm_11cm = 170, hwm_14cx = 85)
#> [1] 0.5
# Output: 0.5 (85/170)

# Example 2: Calculate WHtR for a respondent with missing height.
result <- calculate_waist_height_ratio(hwm_11cm = 999.98, hwm_14cx = 85)
result # Shows: NA
#> [1] NA
haven::is_tagged_na(result, "b") # Shows: TRUE (confirms it's tagged NA(b))
#> [1] TRUE
format(result, tag = TRUE) # Shows: "NA(b)" (displays the tag)
#> [1] "NA"

# Multiple respondents
calculate_waist_height_ratio(hwm_11cm = c(170, 180, 160), hwm_14cx = c(85, 90, 80))
#> [1] 0.5 0.5 0.5
# Returns: c(0.5, 0.5, 0.5)

# Database usage: Applied to survey datasets
# library(dplyr)
# dataset |>
#   mutate(whtr = calculate_waist_height_ratio(hwm_11cm, hwm_14cx))