This refers to a particular risk factor or several risk factors (or protective factors) of interest. It should be clearly reported in this section what the exposure or risk factor (or protective factor) is, and how it may be measured/identified including the nature of the exposure and its intensity and/or the duration of exposure, if relevant. The exposure of interest may be modifiable, and relate to lifestyle habits such as alcohol consumption, smoking or may relate to the environment and occupation such as asbestos and air pollution or conversely, may be non-modifiable, such as family history of the disease.