A Pioneer in Urban Health

While perusing a UN population report in 2000, David Vlahov came across a couple of facts that caught his attention. By 2007, the report said, half of the world's population would be living in cities, and by 2030 the figure would increase to two-thirds. After finding scant attention had been paid to urban health in the literature, Vlahov saw the great need to plan for, rather than react to, the burgeoning health demands of people living in cities. "The report was a real wake-up call," says Vlahov, a former professor at the School and now the director of the Center for Urban Epidemiologic Studies at the New York Academy of Medicine. A burly yet gentle researcher who began his career as a nurse, Vlahov first became involved in urban health issues as a PhD student at the School. In the mid-1980s, he launched a study of a then-mysterious illness among injection drug users in Baltimore. The ALIVE study, now in its 20th year, has provided seminal insights about the epidemiology of HIV/AIDS as well as the effectiveness of antiretroviral treatment and HIV prevention programs. Recognized as a pioneer in the discipline of urban health, Vlahov, PhD '88, MS, says, "The world is rapidly urbanizing; and that makes it an area that needs particular attention."

Given the dense population in cities, the stress, the speedy transmission of infectious disease, the distance from food sources, and so on—aren't cities inherently harmful to health?

Going back to the Industrial Revolution, cities were seen as areas of squalor and slums and particularly poor health. It was really at the middle and end of the 19th century—during the "Sanitary Awakening"—that public health efforts came together to improve sanitation within cities. That dramatically reduced premature mortality primarily from infectious diseases. So there is a historical record of cities as being unhealthy places; but there is also a historical record of cities being areas for problem solving.

What lessons does history offer in terms of urban health?

When you go back and look at mortality records in the United States from the 18th, 19th and 20th centuries, it is interesting because a lot of people might think that infectious disease deaths [and] premature mortality are related to climate or the size of the city. Studies that compared mortality in Baltimore versus Boston, versus New York, versus New Orleans in earlier times have shown it is really not climate or the size of cities, but how fast the cities were growing. Mortality was higher when the rate of urbanization outstripped the resources that were there. I think that is one of the most critical issues now in international health in terms of health challenges for cities.

You mean, making sure the infrastructure keeps up with the pace of growth?

Absolutely. A lot of people talk about megacities over 8 million people and hypercities over 20 million people, but predominantly the major growth over the next 20 to 30 years is going to be in midsize cities—those that have 100,000 people now [growing to] over 500,000. We can see not only the problems we have now, but we can anticipate the expansion of where some of these problems are going to be in the next decades. There are opportunities to plan and bring the best of public health to the forefront.

In the U.S., how should the urban health approach influence what city health departments do?

The health department has traditionally been crisis-oriented: "There's an outbreak of infectious disease, we've got to handle that. There are STDs in the population, we've got to set up clinics..." And so that has been the traditional focus. The more recent focus—and I think [New York City health commissioner] Tom Frieden is a leader in this—is for the health department to [acknowledge] there's more than infectious disease. And in fact, if we look at the major killers in the United States, it's tobacco. It's obesity... And so, how can we get a population to be able to do the right thing when it comes to things related to chronic diseases? That's new ground. That's not something that health departments have really done. I think this is where health departments are trying to push the envelope.

You believe that neighborhoods are key to urban health. Why?

What you have to do [in urban health] is to take the city and consider more refined units. When we look at urban health, we realize there are different types of adverse health outcomes for different neighborhoods. But what is it about some neighborhoods that makes them seem to have better health outcomes than others at the same socioeconomic level? It's these comparative studies that I think are going to be the most important so you can identify factors between neighborhoods that might be used to improve interventions. Urban health is neighborhood health.

Isn't working at the neighborhood level much more difficult for a city health department—trying to do X in this neighborhood and Y in this one and Z over there?

Yes, but if easier is less effective, then how much have you gotten done? What we're talking about here is partnerships. The health department has to see itself as something different than "We're the doctors, and this is our program, and you need to do what the CDC has told us is important to do with you." That's a top-down approach, and how effective can those be ultimately? I think what we need to adopt are "top-out" type of approaches. That really means enlisting people from the community to be extenders of public health.

Give us an example of what you mean.

Some "hard-to-reach" populations, such as undocumented immigrants, are likely to be outside the reach of traditional health care settings, but would be very important to include in a response to an influenza pandemic or bioterror event. So partnering with neighborhood groups to generate "on the ground" rapport can be good planning for catastrophic events and a framework for bi-directional communication and action on other health issues. Public health means the public. And the public needs to be involved.