Mendelian randomization is a method used in epidemiology and genetics to investigate causal relationships between risk factors and health outcomes. This approach utilizes genetic variants as instrumental variables to estimate the causal effect of a modifiable risk factor on a particular outcome. Since genetic variants are randomly assigned at conception and are not influenced by environmental and lifestyle factors, they can be used to mimic a randomized controlled trial in observational studies. Mendelian randomization can help researchers overcome issues such as reverse causation and confounding biases that often arise in traditional observational studies. By using genetic variation as a natural experiment, researchers can provide more robust evidence for causal relationships between risk factors and health outcomes.