QUANTO

Quanto: Sample Size and Power Calculation for Gene–Environment Interaction Studies

Quanto computes sample size and statistical power for epidemiological studies evaluating gene–environment interactions under multiple study designs and trait types.

Key Features:

• Supported Study Designs: Binary disease outcomes: unmatched case-control, matched case-control, case-sibling, case-parent, and case-only designs; quantitative traits: independent individuals and case-parent designs.
• Gene–Environment Interaction Models: Sample size calculation for standard matched case-control, case-sibling, and case-parent designs.
• Stratified Population Analysis: Sample size computation for stratified populations, including multiple ethnic groups.
• Design Efficiency Guidance: Case-sibling design optimized for dominant genes; case-parent design optimized for recessive genes.

Scientific Applications:

• Gene–Environment Interaction Studies: Power and sample size estimation for detecting interactions between genetic factors and environmental exposures in epidemiological research.

Methodology:

Computes the expected value of the likelihood ratio test statistic using conditional logistic regression to estimate power and required sample size across supported study designs, demonstrating that family-based designs (case-sibling and case-parent) typically require fewer matched sets than traditional case-control designs for equivalent power.