The Complexities of Measuring Health and Its Determinants

Ted Schettler, MD, MPH
CHE Science Director, and Science Director of the Science and Environmental Health Network; Coordinator of CHE’s Science Working Group

What is health? How do we measure it? What determines it?  A new report from the Robert Wood Johnson Foundation and the University of Wisconsin Population Health Institute takes a turn at answering these questions.  “County Health Rankings: Mobilizing action toward community health” combines weighted measures of health outcomes and health determinants to define and rank the health of individual counties throughout the US.

Premature mortality and morbidity, estimated by a combination of how healthy people feel and the percent of low birth weight babies, were given equal weight as measures of health outcomes. Various measures of health behaviors, clinical care, social and economic factors, and the physical environment were weighted as measures of health determinants and expressed as composite scores. The website also provides comparative rankings of health outcomes and measures of health determinants at the county level. The authors describe their methods of data collection and analysis in some detail, including a justification of their final choices for weighting individual variables in the composite score. This remarkable effort is worth exploring.

At the outset, the authors had to choose among many candidate health outcomes and determinants. How did they do? Are these the right measures of health or just available statistics? What other health determinants could reveal important insights? Several limits are notable.  Among them: This is a cross-sectional analysis and cannot determine causal relationships.  Genetics, gender, race, and ethnicity are left out. The relative contribution of each group of health determinants always adds up to 100%, regardless of context. (Health behaviors were assigned a weight of 40%, health care 10%, socioeconomic factors 40%, and the physical environment 10% for the final composite score. The justification for these relative weights and alternative opinions are available on the website.) Thus, potential interactions among health determinants are not considered.

For example, the report uses air pollution as a measure of environmental quality, yet it doesn’t acknowledge that people who are socioeconomically disadvantaged are more susceptible to the health effects of air pollution than people who are better off. It’s increasingly clear that air pollution causes more asthma and asthma attacks in children lower on the socioeconomic ladder, independent of other environmental exposures. How should we think about this? Is the problem air pollution, socioeconomic stressors, or both? How does our answer influence what we propose to do? If we ignore interactions, we not only underestimate the impacts of combined eco-social variables in vulnerable groups but also set ourselves up to fail to identify interventions that can have multiple, cross-cutting benefits.  

Despite its inevitable simplifications and assumptions, this detailed report deserves attention and discussion, especially among those of us embracing an ecological model of health. It raises many interesting questions. Is this the right mix of individual and county-wide variables? Are there other measures of health at the county level worth identifying? Are there other measures of environmental quality and integrity that should be added? 
Maybe the report’s biggest contribution will be to set the stage for soliciting ideas about what to do with the information.  Should high-ranking counties be complacent? Should they compete with themselves to improve? Counties struggling with poor health outcomes and multiple adverse health determinants will need something more than disconnected, poorly-coordinated activities. They must understand that risk factors don’t exist in isolation but rather in a complex, interactive web of causation. In those counties, the entire web needs fundamental transformation, achieved through creative, strategic interventions. This is no small task. I think of Donella Meadows’ Places to Intervene in a System in which she says: “There are no cheap tickets to systems change.  The higher the leverage point, the more the system resists changing it.”  Perhaps this is where collaborations like CHE come in…strength in numbers, ideas, and mutual support.

CHE’s Letter to President-Elect Obama

Dear President-Elect Obama:

We write as Partners in the Collaborative on Health and the Environment, a national and international partnership dedicated to protecting the health of our families and communities. Our 3000 Partners include patient group representatives, health professionals, scientists, government officials, environmental health advocates, and citizens from over 48 states and 45 countries.

We provide a respected nonpartisan forum where informed, thoughtful, civil dialogue on health and the environment takes place. We share your dedication to civility and to listening to each other. By our founding mandate, we are prohibited from speaking for all CHE Partners. But we are permitted to convey the shared understanding that has emerged for many of us from six years of intensive dialogue on the implications of the revolution in environmental health sciences for safeguarding human health.

Mr. President, there has been a revolution in environmental health sciences over the past decade. New technologies, new scientific research, and new paradigms of human health and disease have revolutionized our understanding of human health. Indisputably, we face an epidemic of chronic diseases and disorders. Cancer, heart disease, diabetes, metabolic syndrome, obesity, asthma, allergies, learning and developmental disabilities, infertility, neurodegenerative diseases, autoimmune diseases, and many other serious diseases and disorders are epidemic in our time.

There are three core insights from the revolution in environmental health sciences. First, most of these diseases are multifactorial in origin. Second, many begin during fetal and early childhood development. And third, most include among their causes exposures to chemical contaminants, particularly those that persist and bioaccumulate. These contaminants interact with genetic inheritance, gene expression, nutrition, stress, socioeconomic status, and much, much more. We call this the complexity model, or ecological model, of human health. You can call it a multifactorial model just as well. Whatever we call it, few scientists disagree with its main outlines.

The implications of these three core insights from the environmental health science revolution are profound. They bear directly on your administration’s plans for health care reform.

Mr. President, you know our health care system is broken. You want to fix it. You have spoken eloquently of the need to prevent disease. The question we face is HOW to prevent the diseases that are bankrupting our health care system and imposing enormous costs on our economy — to say nothing of their cost in human suffering.

Mr. President, the simple truth is that REAL health promotion and disease prevention requires a national commitment to making our inner and outer environments less toxic and stressful — and richer in nutrients and resilience factors. That is what the multifactorial or ecological model of human health ineluctably implies. What this means is that most of the major policy issues you face — the economy, climate change, health care reform, school reform, food and agriculture and much more — are ultimately your real health promotion and disease prevention policies.

You know that the global financial crisis is unquestionably the single greatest immediate stressor on human health. But to what degree do you recognize how important it is that your policies reduce income disparities, which are the single strongest predictor of disparities in health outcomes? If you want to reduce health care costs, the single most powerful lever to do that is to reduce income disparities and enhance buffers against the stresses of income disparities. The MacArthur Network on Socioeconomic Status and Health is a respected source on this point.

Likewise, you know that climate change is a potentially overwhelming stressor on human health. So your green energy program is not only an economic, national security and environmental priority, as you have said. It is also one of your most important health programs. But to what degree do you recognize that green energy must be accompanied by a commitment to green chemistry and green materials?

Mr. President, it is vital to understand that your chemical management policy will have a profound impact on our health. This is the area in which CHE Partners have the greatest expertise. Chemical contaminants are major contributors to many of the chronic disease epidemics we face. Green energy is necessary but not sufficient to sustaining our health. Green energy, green chemistry, and green materials are all vital components of a health policy that recognizes the implications of the environmental health science revolution and the ecological or multifactorial model of human health.

Beyond green energy, green chemistry and green materials, many of us also share a view that your administration needs to be aware of the health threats of new and emerging technologies. There is increasing concern about the health effects of disrupted electromagnetic fields, biotechnologies and nanotechnologies. Again and again, we have failed to test new technologies for health and safety adequately before loosing them on our citizens and the world.

We cannot expect you to address all of these questions at once, Mr. President. So let us leave you with this summary. Universal health care will fail — it will be far too expensive to sustain — if it is not accompanied by a commitment to real health promotion and disease prevention. The green economy you are committed to creating can only be truly green if it includes green energy, green chemistry, and green materials. That is the path to a just and sustainable country and a just and sustainable world.

Thank you for listening, Mr. President. We wish you well,

Michael Lerner, PhD
Founding CHE Partner

Steve Heilig, MPH
Director of Public Health and Education, San Francisco Medical Society

Génon K. Jensen, MA
Executive Director, Health & Environment Alliance

Philip R. Lee, MD
Chairman, CHE
Professor and Chancellor Emeritus, University of California, San Francisco
Professor of Medicine Emeritus, Stanford University
Former United States Assistant Secretary of Health and Human Services

Elise Miller, MEd
Executive Director, Institute for Children’s Environmental Health

Ted Schettler, MD, MPH
Science Director, Science and Environmental Health Network

Lisette van Vliet, PhD
Toxics Policy Advisor, Health & Environment Alliance