On chronic diseases.

About half of all American adults are living with at least one chronic condition.1 Most chronic diseases are attributable to a short list of modifiable risk factors: high blood pressure, tobacco use, obesity, physical inactivity, excessive alcohol use, and poor diet (see the Behaviors chapter for more data).2 Fortunately, addressing the same risk factors can also serve as strategies to lessen the burden of chronic disease. The risk factors must be addressed at two levels: the individual level (including healthcare interventions) and the population level (policies and environments that promote health). This chapter summarizes the burden of some of the common chronic diseases.