The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape: A Large-Scale Genome-Wide Interaction Study
Fig 4
Power for the combination of screens and gain through a priori filtering for varying configurations of effect sizes across the 4 strata. The figures illustrate (A) the power to detect age-difference, sex-difference or age-sex-difference in at least one of our scans (on Pagediff, Psexdiff and Pagesexdiff, with and without a priori filtering); and (B) a power comparison, comparing approaches with and without a priori filtering on POverall < 1x10-5. We here assume four equally sized strata and a total sample size of N = 300,000 (comparable to the sample size in our BMI analyses). We set bF≤50y = 0.033 (corresponding to a known and mean BMI effect in MAP2K5 region with R2 = 0.037%), bM>50y = 0, and vary bF>50y and bM≤50 on the axes. This strategy allows us to cover the most interesting and plausible interaction effects: Two-way interactions, such as (i) pure age-difference (b≤50y = 0.033, b>50y = 0) and (ii) pure sex-difference (bF = 0.033, bM = 0); and three-way interactions, such as (iii) extreme three-way interaction with opposite direction across AGE and SEX, (iv) 1-strata interaction (bF≤50y = 0.033, bF>50y = bM≤50y = bM>50y = 0), and (v) 3-strata interaction (bF≤50y = bF>50y = bM≤50y = 0.033, bM>50y = 0).