Researchers Seek to Answer a Fundamental Question: What Is Health?

We usually think of health in the context of ill health: if I am not sick than I am healthy. However, according to the World Health Organization, health is more than the absence of disease. But what is it exactly? Now, an interdisciplinary team of scientists is seeking to provide a more specific answer to that question.

The project, one of eight funded by Columbia Mailman Centennial Grand Challenges grants, proposes a framework for understanding, and ultimately, measuring intrinsic health, incorporating three factors rooted in human biology: energy, communication, and structure. Daniel Belsky, a Columbia Mailman epidemiologist and one of the project leads, says this new framework has the potential to transform both public health and medicine, from disease surveillance to doctor’s visits.

The project began in early 2019 when Dean Linda P. Fried held a series of meetings around the university on the subject of what is health. Along with Belsky, the project is led by Columbia Mailman faculty Julie Herbstman in environmental health sciences and Ying Wei in biostatistics. Additional team members come from across the School, Columbia Irving Medical Center, and beyond, bringing expertise in aging, data science, epidemiology, medicine, neuroscience, and more.

In the following Q&A, Belsky explains the process of developing a new conception of health, integrating concepts from many scientific disciplines and levels of human biology.

How does your project go about defining health?

Belsky: We make a distinction between realized health and intrinsic health. Realized health is the ability of people to be and do the things they want and that society expects of them. Realized health is therefore contingent on where and when you live and how society views/treats you. We’re trying to understand the biology that underpins realized health—what biology brings to the table. This is intrinsic health.

What’s new about our approach is that we’re attempting to define the general principles that govern biological health but are not focused on particular biological level of analysis—not just on the cellular level or tissue level, for example. Instead, we want to broadly describe what is required of biology in general for the organism to experience health.

You propose health is governed by three main factors: energy, structure, and communication. Can you elaborate?

Belsky: These three factors are crucial to health at every level of the body. Structure is fundamental to the function of DNA, proteins, cells, tissues, and organs. Energy is crucial to all the functions of the body, from movement to healing. Communication is key to the coordination of biological processes, carried out by neurons in the brain, the endocrine system, and more. In our framework, intrinsic human health is a function of the dynamic and interdependent interaction between these three factors.

Intrinsic health is not dependent on physical attributes. Someone who doesn’t have the use of all their limbs can still have exceptional levels of intrinsic health, especially when they are given the right level of affordances. Think of a sprinter who runs on blades.

What’s it like working with such a diverse group of experts?

Belsky: It’s exciting to integrate epidemiological, clinical, and biological perspectives, but it takes effort to get everyone communicating in the same language. We work to bridge the gap by using visualizations and diagrams. It’s also been helpful to have experts in statistical modeling and causal analysis who can help translate the conceptual models we are developing into models that can be tested in data. We also have a group focused on the social and behavioral determinants that shape—and are shaped by—intrinsic health.

Where are you with this project now?

Belsky: Currently, we’re mapping our theoretical vision of the construct of intrinsic health onto some really exciting new statistical modeling techniques. We are going to use these models in some unique datasets sourced from members of our group that record large numbers of biological measurements over many repeated assessments of the same individuals. The goal is to test proof of concept for the dynamic network of energy, communication, and structure as a fundamental building block of what people experience as health.

Ultimately, we want to develop a way to measure intrinsic health that is much simpler, ideally from a single biological sample—e.g. from blood or saliva. This is something I have experience with from my work on what we call the “Pace of Aging,” which we can think of as the rate at which our health declines as we grow older. In that project, we first developed a measurement of the construct from long-term follow-up data including many different types of assessments and then distilled that into a simple blood test. Now we are applying that blood test in randomized trials to test if different types of interventions can slow aging. We hope to do the same thing with intrinsic health.

How can this test you’re developing be used in the future?

Belsky: Several ways. First, it could provide a metric for population health surveillance. Current methods fail to capture whole-person health. You might have a lot of people diagnosed with a particular disease state but that disease state is not impairing their well-being. Second, it can provide an endpoint for a clinical trial. This is especially useful when we’re testing impacts of complex interventions that affect multiple different health states, such as improved access to primary care, medical homes to coordinate care, improvements to air and water quality, or programs and policies that address social determinants of health. Lastly, it can be integrated into a clinical setting, as a standard preventive test. Ultimately, I think we’d all like to know our own intrinsic health.