bodycomp_reference {bodycompref}

Get body composition reference values

Description

For a given constellation of metric, sex, vertebral level, and age returns either - the reference percentile - the reference z-score - the reference value - the percent of predicted value

Usage

bodycomp_reference(
  metric,
  sex,
  level,
  age,
  type,
  measurement = NULL,
  percentile = NULL,
  z_score = NULL,
  verbose = FALSE,
  digits = 2
)

Arguments

metric

character (vector), body composition metric.

sex

character (vector), ""Female" or "Male"

level

character (vector), used vertebral level

age

integer (vector), age

type

character, type of value to return, either of "percentile", "z_score", "reference_value", "percent_predicted"

measurement

numeric (vector), raw value of measurement

percentile

numeric (vector), percentile to return value for. If both percentile and z_score are given, only percentile is evaluated

z_score

numeric (vector), z score to return value for. If both percentile and z_score are given, only percentile is evaluated

verbose

logical, should messages be displayed

digits

integer, digits to round return value to

Details

Reference models are available for the following metrics: - CSMA: Cross-sectional muscle area [cm²] - SMI: Skeletal Muscle Index [cm²/m²] - SMRA: Skeletal Muscle Radioattenuation [Hounsfield Units (HU)] - SMG: Skeletal Muscle Gauge [cm² * HU/ m²] - CSFA: Cross-sectional (subcutaneous) fat area [cm²] - SATI: Subcutaneous Adipose Tissue Index [cm²/m²] - SATRA: Subcutaneous Adipose Tissue Radioattenuation [HU] - SATG: Subcutaneous Adipose Tissue Gauge [cm² * HU/ m²] - CSVFA: Cross-sectional Visceral Fat Area [cm²] - VATI: Visceral Adipose Tissue Index [cm²/m²] - VATRA: Visceral Adipose Tissue Radioattenuation [HU] - VATG: Visceral Adipose Tissue Gauge [cm² * HU/ m²] - TAT: Cross-sectional Total Adipose Tissue Area [cm²] (SATA + VATA) - TATI: Total Adipose Tissue Index [cm²/m²] (SATI + VATI) - VAT_SAT_ratio: VAT/SAT ratio []

Measurement values must be >= -124 for SATRA and VATRA, <= -1 for SATG and VATG, and >= 1 for all other metrics.

The reference values are based on LMSP models constructed from the Framingham Heart Study published in the following publications: - Marquardt JP, Tonnesen PE, Mercaldo ND, Graur A, Allaire B, Bouxsein ML, Samelson EJ, Kiel DP, Fintelmann FJ. Subcutaneous and Visceral adipose tissue Reference Values from Framingham Heart Study Thoracic and Abdominal CT. Investigative Radiology, 2024. - Tonnesen PE, Mercaldo ND, Tahir I, Dietrich ASW, Amari W, Graur A, Allaire B, Bouxsein ML, Samelson EJ, Kiel DP, Fintelmann FJ. Muscle Reference Values from Thoracic and Abdominal CT for Sarcopenia Assessment: The Framingham Heart Study. Investigative Radiology, 2023.

Value

numeric, corresponding percentile

Author(s)

J. Peter Marquardt

Examples

bodycomp_reference(metric=c("CSFA", "CSFA"), sex=c("Female","Male"),
                  level=c("T5","L3"), age=c(42,68), measurement=c(100,200),
                  type = "percentile")