Can the epidemiologic triad can be applied to a disease that not infectious? Consider a smoking-related disease (Figure 3). If smoking (or more specifically, a carcinogen in the smoke of the cigarette) causes the disease, those who manufacture, sell and distribute cigarettes are vectors, bringing the disease-causing agent to the susceptible host. Diagramming the epidemiologic triad also indicates potential interventions to reduce disease in the population. In this example, clean indoor air legislation, advertising potential harm from smoking or establishing workplace smoking cessation programs could change the environment and reduce the exposure of host to agent. Conversely, increased advertising from cigarette manufacturers or increased numbers of vendors would increase exposure of host to agent.