Molecular epidemiology is an interdisciplinary field that integrates advanced molecular and cellular laboratory methods into population-based epidemiological studies. It investigates the molecular basis of disease etiology, progression, and susceptibility by examining interactions between genetic factors, environmental exposures, and other biological determinants at the molecular level. Utilizing molecular biomarkers in biological specimens, this approach aims to elucidate disease mechanisms, identify risk factors, enhance disease classification, and inform targeted prevention and intervention strategies, thereby advancing precision public health and disease control.