GitHub for SPRINT HIA:
https://github.com/ArashDer/SPRINT-HIA/
Shiny app for calculation of attributable fraction and cases:
To facilitate simulation of HIA in different scenarios of exposure levels, exposure-response-function, we have made a simple Shiny app. In this app, the user can enter the desired exposure level in the biological sample, the ERF with the option to provide the 95%CI, as well as extra options to provide the baseline prevalence of the outcome (and total population). The app will return the calculated attributable fraction as well as attributable cases, with a graphical representation of the changes of AF and prevalence with the increase in exposure.
Go to app: Shiny HIA
https://aderakhshan.shinyapps.io/SPRINT-HIA4/
Monte Carlo simulation Shiny App
https://aderakhshan.shinyapps.io/Monte_Carlo_Simulation/
This is a Monte Carlo simulation tool to estimate potential health effects from exposure to multiple pesticides. It lets the user define exposure distributions and dose–response slopes for three pesticides, combine them under different interaction assumptions (additive, synergistic, antagonistic), and then calculate population‑level health impacts.
How it works:
- Inputs (sidebar):
- Number of simulations (e.g. 10,000).
- Exposure parameters for pesticide 1– pesticide 3 (lognormal mean & SD).
- Dose–response slope ranges (95% CI).
- Interaction type (additive, synergistic, antagonistic) with multiplier.
- Population size and disease prevalence.
- Simulation (server):
- For each pesticide:
- Draw exposures from a lognormal distribution.
- Draw slopes from a normal distribution based on CI.
- Multiply exposure × slope → effect distribution.
- Combine pesticides effects:
- Additive = sum of effects.
- Synergistic = sum × multiplier (>1).
- Antagonistic = sum × multiplier (<1).
- Interpret combined effect as Relative Risk (RR).
- Compute Attributable Fraction (AF) = (RR-1)/RR.
- Compute Attributable Cases (AC) = AF × (population × prevalence).
- For each pesticide:
- Outputs (main panel):
- Histogram: distribution of simulated health effects.
- CDF plot: cumulative distribution of health effects.
- Summary stats: mean and 95% CI for AF and AC, plus descriptive stats of effects.
This app lets you explore how uncertain exposures and dose–response relationships for multiple pesticides translate into population‑level health risks. It shows both the distribution of possible outcomes and summary measures like attributable fraction and cases.
Further information on the methods and interpretation of the results are provided in the README section of the app.