The United States spent $2.5 trillion on health care in 2009, more per capita than any other nation. Yet our country is ranked 32nd in the world in life expectancy, and rates of conditions such as diabetes and obesity have increased dramatically in recent years.

If we hope to address spiraling medical costs and improve the health of all Americans, we need to begin focusing on the policies — in fields such as transportation, energy, education and agriculture — that shape the world outside the doctor’s office.

But how? Policymakers are already juggling shrinking budgets, crumbling infrastructure and competing priorities.

A recently released report from the National Research Council offers a solution. The study, “A Framework and Guidance for Health Impact Assessment,” points out that good health is determined by more than money spent on the health care system. An NRC committee on health impact assessments, of which I am a member, took an in-depth look at why they are needed.

Similar to the way a Congressional Budget Office score predicts the fiscal impact of a proposed policy, an HIA identifies the likely effect on health of a decision in another field, such as building a major roadway, revitalizing a neighborhood or developing energy or agricultural policy. HIAs can help decision-makers identify unintended risks, reduce unnecessary costs and leverage opportunities to improve the health of their communities.

As a doctor, I’ve often cared for diabetics who struggle to follow exercise recommendations because there’s nowhere nearby that’s safe to exercise. I’ve seen patients with frequent asthma attacks exacerbated by living in housing with mold and poor ventilation. I’ve given diet advice to parents of overweight children, only to find that they live in a neighborhood with no grocery store for miles and eat school lunches that should but often don’t meet current nutrition guidance.

Many of the most urgent health problems facing the nation, such as diabetes, asthma, obesity and injury, are shaped by conditions in the places where we live, work and go to school.

An HIA can help ensure constituent concerns are well-addressed, obstacles are overcome and proposed projects move forward.

In a decision on oil and gas leasing on the North Slope of Alaska, local residents, who were generally supportive of energy development because of the revenue it brings, opposed parts of a proposal that would expand leasing into hunting and fishing areas vital to the community’s food supply. Collaboration on the HIA contributed to a compromise leasing plan that included several new protections for health. It also helped overcome a sharp divide among stakeholders and stemmed the threat of litigation.

HIAs often build support for well-planned projects. After an HIA showed that the BeltLine light-rail project in Atlanta would offer many health benefits, such as improving access to grocery stores, green spaces and safe places to exercise, the project received several million dollars from a federal government grant, as well as private funding.

The states are leading the way, finding opportunities to make health an everyday part of public decision-making through the use of HIAs.

Alaska, which regards HIAs as a “best practice” for responsible development, recently announced a new program to use them as part of the permitting process for large projects throughout the state.

In Oregon, a robust network of experienced HIA practitioners has sprung up among government, local health departments, nonprofits and others.

Massachusetts will use an HIA to inform major transportation projects.

At the local level, cities such as Minneapolis and Atlanta are becoming hotbeds of HIA activity.

In the coming year, Congress will debate such major legislation as the farm bill and the Surface Transportation Extension Act. At first glance, these bills might not seem important to health, but they will have far-reaching consequences for the health and well-being of American communities.

Factoring health into these decisions offers a huge opportunity to maximize benefits and ultimately reduce medical costs. HIAs — and the guidance from the National Research Council — give us a way to do just that.

Aaron Wernham, M.D., is director of the Health Impact Project, a collaboration of the Robert Wood Johnson Foundation and the Pew Charitable Trusts.