Sample Size Calculator (Continuous outcome)

Result

Parameter interpretation

Power: Study the probability of being able to detect the true effect

Alpha: Type-I error rate, defaults to 0.05

βyx: Regression coefficient, representing the potential causal relationship between exposure and outcome, i.e. the beta value after MR analysis

R2: Explanation of exposure by instrumental variables,The input required is the joint R2, which can be obtained by directly summing the R2 of each of the exposed SNPs to obtain the joint R2, while ensuring that there are no linkage disequilibrium(LD)

VarX: Variance of exposure, strength of association between instrumental variables and exposure, The variance or standard deviation can usually be found in the data source, usually within the annexes

VarY: Variance of outcome, the degree of dispersion inherent in the ending variable, The variance or standard deviation can usually be found in the data source, usually within the annexes

Sample Size Calculator (Binary outcome)

Result

Parameter interpretation

Power: Study the probability of being able to detect the true effect

Alpha: Type-I error rate, defaults to 0.05

K: Proportion of cases in outcome

OR: odds ratio:The effect of the exposure factor on the outcome, i.e. the multiplicative increase in the odds of the outcome occurring when the exposure factor is increased by one unit.

R2: Explanation of exposure by instrumental variables,The input required is the joint R2, which can be obtained by directly summing the R2 of each of the exposed SNPs to obtain the joint R2, while ensuring that there are no linkage disequilibrium(LD)

1. Calculating statistical power in Mendelian randomization studies Marie-Jo A Brion, Konstantin Shakhbazov, Peter M Visscher International Journal of Epidemiology 2013 42: 1497-1501

2. mRnd https://github.com/kn3in/mRnd