vitd.curve: Generate Vitamin D curves
In SimVitD: Simulation Tools for Planning Vitamin D Studies

vitd.curve

R Documentation

Generate Vitamin D curves

Description

Generates a vitamin D status profile curve for each individual in a group

Usage

vitd.curve( n = 1, type = c("placebo","fixed-dose","dynamic-dose"), start = 0, end = 1,  
    mu = 45, amplitude = 35, dyn.dose.thresh = 50, sd.mu = 5, sd.amplitude = 5, 
    sd.dyn.dose.thresh = 5, supp.dose = 20, supp.dose.rate = Inf, weight = 1, 
    sd.weight = 0, min.thresh = 10, north.hemi = TRUE, res = 40 )

Arguments

`n`	Number of curves to simulate.
`type`	One of "placebo", "fixed-dose", "dynamic-dose".
`start`	Time in units of years when trial started.
`end`	Time in units of years when trial ended.
`mu`	The mean level of 25OHD in the trial arm around which there is cosine variation.
`amplitude`	Amplitude of cosine function describing variation around `mu`
`dyn.dose.thresh`	Threshold for the concentration-controlled scheme.
`sd.mu`	Standard deviation levels around mean; this is the standard deviation of H in vignette.
`sd.amplitude`	Standard deviation of the amplitude.
`sd.dyn.dose.thresh`	Standard deviation of the participant retained concentration in the concentration-controlled trial.
`supp.dose`	The 25OHD nmol/l equivalent for dosage in fixed-dose supplementation.
`supp.dose.rate`	Concentration parameter for fixed-dose scheme uptake. Large values imply that all participants derive the same equivalent.
`weight`	For fixed-dose supplementation, this is the expected value of the proportion of the dose which is always utilized.
`sd.weight`	Standard deviation of weight
`min.thresh`	The minimum detectable threshold of 25OHD. Defaults to 10 nmol/l.
`north.hemi`	Summer/winter months as in the Northern Hemisphere if `TRUE` and Southern Hemisphere if `FALSE`.
`res`	Resolution parameter for plotting of vitamin D curves.

Value

vitd.curve returns an object of class vitd.curve. Curve parameter settings are returned. The slot curves give the curve specific parameters for each of the n generated curves. Additionally, time used for plotting gives time values passed to plot.vitd.curve.