Erin Shigekawa, a health policy fellow at the Center for Healthcare Research and Transformation at the University of Michigan, wrote this for the Public's Health blog on Philly.com. The views are the author's.

We're number one, and that's not a good thing. Compared with other countries, the U.S. imprisons the most people in the world, and among developed nations, it leads in the number and proportion of imprisoned people.

Since the 1970s, our correctional population has exploded by 700 percent. Many factors have contributed, namely the "war on drugs," an underfunded mental-health system, and mandatory minimum sentencing laws.

Incarceration is disproportionately concentrated in low-income and often nonwhite communities.

Despite similar rates of illicit drug usage across racial groups (9.6 percent among blacks, 8.8 percent among whites), African Americans are 13 times more likely to be imprisoned for drug charges.

Jails and prisons have become an ill-equipped substitute for mental-health facilities. A recent report by the Treatment Advocacy Center estimated that 356,268 people were in jail and prisons with severe mental illness in 2012, 10 times the number in state hospitals.

What does this have to do with health? A new report by the Vera Institute of Justice indicates that overall, people in jail or prison have worse health than the general public. They experience higher rates of chronic and infectious diseases, substance abuse, and mental illness.

Incarceration may expose inmates to more health risks, especially for those with mental illness. Solitary confinement has an especially harmful impact, including anxiety, self-harm, and disabling long-term effects.

After release, people face a host of obstacles that can affect health. Several states have upheld a ban that bars those with a drug-related felony from getting nutrition assistance (formerly food stamps) or cash assistance. Often, those with prison records are ineligible for student loans, cutting access to education.

Michelle Alexander, author of The New Jim Crow, calls these many policies "legalized discrimination."

Some in public health refer to mass incarceration as an epidemic since it also harms families and communities. Children with incarcerated fathers are much more likely to experience homelessness.

Ernest Drucker, author of A Plague of Prisons, has noted that mass incarceration "exhibits all the characteristics of an infectious disease - spreading most rapidly by proximity to prior cases."

What has and can be done? First - prevention. In August 2013, Attorney General Eric Holder released guidelines to reduce the use of harsh mandatory minimum sentencing for low-level, nonviolent drug offenses with no connection to large-scale drug activity. We also need to build a stronger mental-health infrastructure and care for individuals dealing with substance abuse.

We must recognize the negative impact of post-release bans on social programs. Policymakers should modify or lift these bans.

Lastly, we need recognition that mass incarceration is a public health concern. A recent New York Times editorial called for a multilevel approach that assembles professionals from public health and criminal justice to address the issue. Let's talk.