Objectives:
Health Impact Assessment (HIA) is often defined as “a combination of procedures, methods, and tools by which a policy, program, or project may be judged as to its potential effects on the health of a population, and the distribution of those effects within the population”. Thus, HIA is a tool to help decision-makers better recognize the health consequences of their decisions.

The use of HIA has been growing in the United States in recent years as public health, planning, and transportation professionals are recognizing that land use and transportation planning decisions can have a substantial impact on the public’s health. The objective of this work was to document the growth of HIA in the United States.

Methods:
A list of completed HIAs was derived from HIAs in which the co-authors were involved, networking at various professional meetings and through inquiries received by the co-authors. In addition, a literature search was conducted on Medline and a message was disseminated on the HIA-USA listserv requesting additional studies. A list of completed HIA training courses and other on-going HIA related projects was also collected.

Results:
There were 10 courses conducted from 2005 to 2007 with over 400 people trained. Courses ranged from half-day trainings at national conferences to more intense 2 to 3 day courses in which slots for participation in the courses were competitive. Many organizations including the Centers for Disease Control and Prevention (CDC), The University of California at Los Angeles (UCLA), the San Francisco Health Department, the American Planning Association, and the National Association of County and City Health Officials worked together to conduct these trainings.

The 21 completed HIAs examined wage policies, walk to school programs, residential and commercial redevelopment, after school programs, land use planning, farm policy, transportation, parks, power plants, and public subsidies for housing and heating. Health disparities were important in HIAs on housing, urban redevelopment, home energy subsidies, and wage policy. The HIAs were conducted in California (n=12), Georgia (n=2), Massachusetts (n=2), Alaska (n=2), Minnesota (n=1), New Jersey (n=1) and Florida (n=1).

Most HIAs used both qualitative and quantitative measures to describe existing conditions and in forecasting health impacts. Predicted quantitative health outcomes included physical activity, obesity, life expectancy, sleep disturbance, and pedestrian injuries. Predictive qualitative measures included asthma, academic performance, teen sexual behavior, stress, personal safety, mental health, social capital, well-being, and air and water quality.

Investigators for the HIAs included local and federal public health officials, faculty from schools of public health, medicine and architecture and private consultants. Some of the HIAs were conducted without external funding by investigators within the scope of their health department positions, while other HIAs were conducted with funding from the Robert Wood Johnson Foundation, the CDC, and county health departments.

Most of the HIAs included recommendations to mitigate predicted adverse health outcomes and/or to increase predicted health-promoting outcomes. Information on the impact of the HIAs is available for only a few of the 16 HIAs reviewed. However, in San Francisco, the Trinity Plaza and Rincon Hill HIAs led to project design changes that added affordable housing and funds for parks and community facilities, the living wage ordinance HIA contributed to its passage by the city board of supervisors, and the public housing flooring policy HIA led to better recommendations for design.

UCLA recently received funding to build and maintain web-based, practice-focused clearinghouse for HIA in the U.S. and to promote its use through workshops with major national organizations of policy-makers and health professionals. The clearinghouse will include a searchable library of HIAs, an interactive module to demonstrate the utility of HIAs, and an interactive online training tool.

Conclusions:
There is a growing interest in using HIAs in the U.S. and the issues examined in these HIAs are diverse, suggesting that HIA methods may be useful for a wide range of projects and policies. The results of these HIAs highlight the multidisciplinary nature of HIAs and the need for effective collaboration between public health practitioners and non-traditional partners such as those from planning and transportation.

Decisions about projects and policies that affect the health of communities are being made on a daily basis throughout the United States. HIAs are designed to offer the best available data to decision-makers to inform them about the health impacts of their decisions. We believe that HIA is a promising new approach to identifying the impacts of a wide variety of policy and infrastructure changes in a way that allows health outcomes to be appropriately factored into complex decisions.

Support:
Many of the Health Impact Assessments were funded by the Robert Wood Johnson Foundation and CDC.