Epidemiology A discipline of research that examines relationships between factors associated with increased or decreased risk of disease in populations. Causal relationships cannot be determined by epidemiological research.

• 流行病学:是一门研究人群中与疾病危险性增加或下降相关因素间关系的学科。该学科一般并不能确定各因素与疾病间的因果关系。