HIMA (version 2.3.3)

hima_efficient: Efficient high-dimensional mediation analysis

Description

hima_efficient is used to estimate and test high-dimensional mediation effects using an efficient algorithm. It provides higher statistical power than the standard hima. Note: efficient HIMA is only applicable to mediators and outcomes that are both continuous and normally distributed.

Usage

hima_efficient(
  X,
  M,
  Y,
  COV = NULL,
  topN = NULL,
  scale = TRUE,
  FDRcut = 0.05,
  verbose = FALSE,
  parallel = FALSE,
  ncore = 1
)

Value

A data.frame containing mediation testing results of significant mediators (FDR <FDRcut).

Index:

mediation name of selected significant mediator.

alpha_hat:

coefficient estimates of exposure (X) --> mediators (M) (adjusted for covariates).

alpha_se:

standard error for alpha.

beta_hat:

coefficient estimates of mediators (M) --> outcome (Y) (adjusted for covariates and exposure).

beta_se:

standard error for beta.

IDE:

mediation (indirect) effect, i.e., alpha*beta.

rimp:

relative importance of the mediator.

pmax:

joint raw p-value of selected significant mediator (based on divide-aggregate composite-null test [DACT] method).

Arguments

X

a vector of exposure. Do not use data.frame or matrix.

M

a data.frame or matrix of high-dimensional mediators. Rows represent samples, columns represent mediator variables. M has to be continuous and normally distributed.

Y

a vector of continuous outcome. Do not use data.frame or matrix.

COV

a matrix of adjusting covariates. Rows represent samples, columns represent variables. Can be NULL.

topN

an integer specifying the number of top markers from sure independent screening. Default = NULL. If NULL, topN will be 2*ceiling(n/log(n)), where n is the sample size. If the sample size is greater than topN (pre-specified or calculated), all mediators will be included in the test (i.e. low-dimensional scenario).

scale

logical. Should the function scale the data? Default = TRUE.

FDRcut

Benjamini-Hochberg FDR cutoff applied to select significant mediators. Default = 0.05.

verbose

logical. Should the function be verbose? Default = FALSE.

parallel

logical. Enable parallel computing feature? Default = FALSE.

ncore

number of cores to run parallel computing Valid when parallel = TRUE.

References

Bai X, Zheng Y, Hou L, Zheng C, Liu L, Zhang H. An Efficient Testing Procedure for High-dimensional Mediators with FDR Control. Statistics in Biosciences. 2024. DOI: 10.1007/s12561-024-09447-4.

Examples

if (FALSE) {
# Note: In the following example, M1, M2, and M3 are true mediators.

# Y is continuous and normally distributed
# Example (continuous outcome):
data(ContinuousOutcome)
pheno_data <- ContinuousOutcome$PhenoData
mediator_data <- ContinuousOutcome$Mediator

hima_efficient.fit <- hima_efficient(
  X = pheno_data$Treatment,
  Y = pheno_data$Outcome,
  M = mediator_data,
  COV = pheno_data[, c("Sex", "Age")],
  scale = FALSE, # Disabled only for simulation data
  FDRcut = 0.05,
  verbose = TRUE
)
hima_efficient.fit
}