Which study relates to the origin or causation of a disease?

The study that focuses on the origin or causation of a disease is etiology. Etiology examines the various factors that contribute to the development of a disease, including biological, environmental, and genetic influences. Understanding etiology is crucial for identifying risk factors, developing prevention strategies, and informing treatment approaches. This field is fundamental in medical research, as it helps to pinpoint the underlying reasons for diseases, which can lead to more effective interventions and therapies.

While epidemiology studies the distribution and determinants of health-related events in populations, it does not focus solely on the origin of diseases. Pathology, on the other hand, primarily addresses the structural and functional changes in tissues caused by disease, and immunology studies the immune system's responses to pathogens and its role in disease processes. Therefore, the most accurate choice for identifying the study related specifically to the causation of disease is etiology.