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Calculate Years of Life Lost (YLL) due to Radiation Exposure

YLL.Rd

Computes the expected Years of Life Lost (YLL) attributable to radiation exposure. This function integrates site-specific baseline mortality and all-cause mortality rates with user-specified excess risk models (ERR/EAR) to estimate the expected reduction in life expectancy due to radiation-attributable cancer mortality.

The function supports both single-age and protracted exposure scenarios and allows for uncertainty quantification via Monte Carlo sampling.

Usage

YLL(exposure, reference, riskmodel, option)

Arguments

exposure

A list specifying the exposure scenario:

  • agex — age(s) at exposure (scalar or numeric vector).

  • doseGy — dose(s) in Gray (Gy), scalar or vector of same length as agex.

  • sex — sex indicator (1 = male, 2 = female).

reference

A list specifying baseline and all-cause mortality information:

  • baseline — data.frame of site-specific mortality (or incidence) rates per person-year, including columns age, male, and female.

  • mortality — data.frame of all-cause mortality rates (per person-year) with same structure and age range as baseline.

These should correspond to the same population or region.

riskmodel

A list defining the excess risk model, typically of the form:

  • err and/or ear — sublists each containing:

    • para — vector of model parameters.

    • var — variance–covariance matrix of parameters (for multi-parameter models).

    • ci — 95% confidence bounds for a single-parameter model (alternative to var).

    • f(beta, data, lag) — function returning age-specific excess risks.

option

A list of optional settings:

  • maxage — maximum attained age for accumulation (default: 100).

  • err_wgt — weight between ERR (1) and EAR (0) transfer models.

  • n_mcsamp — number of Monte Carlo draws for uncertainty estimation (default: 10,000).

  • alpha — significance level for confidence intervals (default: 0.05).

Value

A named numeric vector with point and interval summaries of cumulative excess risk, typically including:

  • mle: point estimate,

  • mean, median: Monte Carlo summaries,

  • ci_lo, ci_up: confidence interval.

Values are per person; multiply by 1e4 or 1e5 to report per 10,000 or 100,000.

Details

The YLL estimate integrates the excess mortality over age, weighted by remaining life expectancy, producing an interpretable measure of life expectancy loss attributable to radiation. The computation uses region- and sex-specific mortality data provided in the package or supplied by the user.

Typical usage involves pairing YLL() with CER() or population_YLL() for complementary assessments of probability-based and life loss–based risk metrics.

See also

CER, population_YLL, population_LAR

Examples

set.seed(100)
## Example 1: All-solid cancer mortality (Region 1, female, 0.1 Gy at age 15)
exp1 <- list(agex = 15, doseGy = 0.1, sex = 2)
ref1 <- list(
  baseline  = Mortality[[1]]$allsolid,
  mortality = Mortality[[1]]$allcause
)
mod1 <- LSS_mortality$allsolid$L
opt1 <- list(maxage = 100, err_wgt = 1, n_mcsamp = 10000)

YLL(exposure = exp1, reference = ref1, riskmodel = mod1, option = opt1)
#>         mle        mean      median  ci_lo.2.5% ci_up.97.5% 
#>   0.2408580   0.2437128   0.2417327   0.1884222   0.3090655 

## Example 2: Leukaemia incidence (Region 4), male, 100 mGy evenly across ages 30–45
exp2 <- list(agex = 30:44 + 0.5, doseGy = rep(0.1 / 15, 15), sex = 1)
ref2 <- list(
  baseline  = Incidence[[4]]$leukaemia,
  mortality = Mortality[[4]]$allcause
)
mod2 <- LSS_incidence$leukaemia$LQ
opt2 <- list(maxage = 60, err_wgt = 0, n_mcsamp = 10000)

YLL(exposure = exp2, reference = ref2, riskmodel = mod2, option = opt2)
#>           mle          mean        median    ci_lo.2.5%   ci_up.97.5% 
#>  4.118829e-03  4.046922e-03  4.046761e-03 -6.836959e-05  8.171657e-03