An aging population and growing disease burden will require a large and specialized health care workforce by 2025.

As the US population ages, the increasing prevalence of chronic disease and complex medical conditions will have profound implications for the future health care system. We projected future prevalence of selected diseases and health risk factors to model future demand for health care services for each person in a representative sample of the current and projected future population. Based on changing demographic characteristics and expanded medical coverage under the Affordable Care Act, we project that the demand for adult primary care services will grow by approximately 14 percent between 2013 and 2025.