In our annual HealthLeaders 20, we profile individuals who are changing healthcare for the better. Some are longtime industry fixtures; others would clearly be considered outsiders. Some are revered; others would not win many popularity contests. All of them are playing a crucial role in making the healthcare industry better. This is the story of Nicholas Christakis.
This profile was published in the December, 2011 issue of HealthLeaders magazine.
"People are connected, so their health is connected … We need to think about health interventions in a way that's more collective and not as individualistic."
Trained as both a physician and a social scientist, Nicholas Christakis, MD, PhD, MPH, says his intellectual toolkit spans a broad set of concepts and materials. "I live my life at the intersection of different ideas. I try to see if there are ways to bring knowledge from disparate fields to improve public health and public policy."
Christakis is a professor of medicine and medical sociology at Harvard Medical School, and is the scientific founder of Activate Networks, Inc. (formerly Mednetworks.)
For the past decade Christakis, along with his long-time collaborator, James Fowler, PhD, professor of political science and medical genetics at the University of California, San Diego, has been studying human social networks and their effects on health. These aren't Facebook networks. Christakis analyzes the old-fashioned face-to-face networks that people form with friends, families, neighbors, coworkers, and others.
"We look at how human beings connect to one another, how we create these elaborate networks, and what it means for our lives. We're trying to understand, for example, the social determinants of ill health. How is it that social phenomena can be more responsible for how we as a society or as individuals live or die than clinical or biological factors?"
His work in the areas of depression, obesity, and smoking has been published in the New England Journal of Medicine and the Proceedings of the National Academy of Sciences. Christakis is co-author with Fowler of Connected: The Surprising Power of Our Social Networks and How They Shape Our Lives.
Most of the network research takes place at The Christakis Lab at Harvard University in Boston and involves elaborate computer modeling.
In one of the lab's best known studies, data from the famous Framingham Heart Study was used to demonstrate how weight gain in one person might ripple though a social network. In looking at the relationships of 12,000 people, Christakis and Fowler found that a person's chances of becoming obese increase by 57% when a friend becomes obese; by 40% if a sibling becomes obese; and by 37% if a spouse becomes obese.
"When people around you gain weight, your attitude about what constitutes an acceptable body size can change, and you might gain weight, too," Christakis explains.
One of his favorite studies involves a new way to predict epidemics. It uses the friendship paradox (in 25 words or less: A given person's friends are probably more popular than that person) to identify who's at the center of a social network and who's at the margins. Think of the people in the center as trendsetters or, as Christakis likes to call them, "early warning systems." Just as this group might be early adopters for fashion, technology, music, etc., they also get sick first and the illness spreads through the entire network.
Christakis says the overarching idea of his social network research is that "people are connected, so their health is connected." Your individual health depends not only on your own choices and behaviors but also on the people who surround you, including people you know and people you don't know.
Within a network, the fact that a person unknown to you has the flu has meaning for you, explains Christakis. "What this suggests is that we need to think about health interventions in a way that's more collective and not as individualistic."
Christakis says studying networks is not just an intellectual exercise. "What can we do with this knowledge? We know that germs flow though networks, ideas about drug prescriptions and health practices flow through networks, and behavioral phenomena such as weight gain or smoking cessation flow through networks. How can we exploit this knowledge to intervene in the network to make the world a better place?"
Christakis and Fowler are interested in how they can take a network of people in a school or workplace and identify the influencers to target for behavior change. "Who can influence people to wear their safety helmets or take their blood pressure medication or quit smoking?"
Harvard has licensed information from Christakis Lab to a start-up called Activate Networks Inc., which was cofounded by Christakis. Companies interested in tapping in to the power of social networks include Accenture, Cardinal Health, Humana, Merck, Nortel, P&G, and UBS.
Among ANI's projects is a deal with Healthways, a disease management company, to use social networks to improve wellness in the workplace. A pharmaceutical company is working with ANI to see how social networks can be used get physicians to adopt innovations and superior prescribing behaviors.
Christakis admits that he sees networks everywhere. "When I began studying networks, it was like I put on different glasses. I see how my actions affect others and their actions affect me."
This article appears in the December 2011 issue of HealthLeaders magazine.
Margaret Dick Tocknell is a reporter/editor with HealthLeaders Media.
