Study on Aging Challenges Common Perceptions of What ‘Healthy’ Means
Impact of obesity on health contingent on physical, mental health
By most medical standards, being healthy means you’re not battling a major disease like cancer, diabetes or cardiovascular disease. But a new study from the University of Chicago questions this traditional method of measuring health.
The problem, the study posits, is that by defining health as the absence of chronic diseases of major organ systems in older adults, key factors are overlooked.
According to Martha McClintock, the lead author of the study, fully one-quarter of the U.S. population, which is identified as healthy by traditional measures, is at some risk of dying or becoming incapacitated within five years when factoring in mental health and the occurrence of a broken bone after age 45.
“That’s really interesting and novel for us because it was not predicted by the pattern of organ system disease,” said McClintock, the David Lee Schillinglaw distinguished service professor of the departments of psychology and comparative human development at the University of Chicago.
For the study, McClintock and her fellow researchers used what they called a comprehensive model of health and aging, which extends measurement factors to health behaviors, psychological health, sensory abilities, neuroimmune function and mobility; along with bio-measures such as blood pressure, heart rate, height and weight, and testing for diabetes. Each of the factors were assessed at the beginning of the study and then five years later on a nationally representative sample of more than 3,000 people ranging in age from 57 to 85.
“It’s a very rich data set but that was the whole point: to try and characterize each person in terms of a mosaic of all of these traits, rather than just saying, ‘Let’s look at blue chips or red chips,’” McClintock said. “We’re going to look at the pattern of them, and then ask how all these measures hang together. Is there one giant characteristic of aging? Or are there are 100 ways to age?”
The Impact of Obesity on Health
In analyzing the data, researchers discovered participants could be organized into six distinct health classes based on different patterns of health and well-being. Some of these health classes are more complex than others. Obesity, for example, is typically viewed as a severe health risk: a person is grossly overweight, immobile and has diabetes and/or hypertension.
But researchers found that not all people who are overweight epitomize this description or fit into the same class of "obese." In fact, while the findings show some participants fall into a health class characterized by our traditional view of obesity as a severe health risk, roughly 22 percent of obese older adults are among the healthiest in the general population, the study showed.
“They didn’t have many diseases, and so what this says is being overweight, per se, doesn’t necessarily mean you are in bad health. And in fact, they were the healthiest,” McClintock said of the participants in what researchers called the "robust obese" health class.
People in this class were the least likely of all to die or become incapacitated within five years. Findings showed these people were healthier than adults of a normal weight who have one minor condition that’s not life-threatening like arthritis or peptic ulcers.
“We really need to think about being overweight in context of all these other aspects of physical and mental health,” McClintock said.
Researchers did find unhealthy overweight participants who did not fall into the "robust obese" health class but two additional health classes. One is characterized by immobility, diabetes and hypertension. These people had a higher probability of becoming incapacitated or dying within five years.
The least healthy participants were overweight, had diabetes, hypertension, multiple organ diseases, poor mental health, poor sensory function, and immobile, among other health issues.
“Everything is bad. This is the group that had higher mortality and risk of being incapacitated,” McClintock said. “And these last two groups are not surprisingly more likely to be poor, and also more likely to be women.”
Redefining the Characteristics of Health
Researchers involved with the study hypothesized that if these often-overlooked factors were essential to health, a more accurate picture of mortality and incapacity would emerge. One that’s “better than just looking at traditional organ system disease,” McClintock said.
Study findings revealed just that: one-quarter of people who were considered healthy by most medical standards were found to be at some risk of dying or becoming incapacitated within five years when additional health factors were considered, including mental health. This resulted in two emergent health classes: one characterized by breaking a bone after age 45 and the other by poor mental health.
“These are novel groups which are guiding our main point that mental health, the mind and the nervous system, balance, muscle and mobility are essential parts of health at this age,” McClintock said. “They’re not just extras.”
One in seven people break a bone during or after middle age, according to the study. Participants who broke a bone after age 45 were of average health, but were more likely to become incapacitated or die within in five years.
“This wasn’t breaking a hip at the end of life. This is having a broken bone that healed. They were still active and not immobilized because of it. And yet they were more likely to become incapacitated five years later,” McClintock said. “The reason is because of frailty and because of accidents. Frailty means muscle strength, nervous system functioning, poor balance and trouble walking around the block.”
As for the connection to becoming incapacitated five years later, McClintock and her team think it shows early nervous system or muscle problems.
“Weakness, balance and instability or judgment are all connected to the nervous system,” she said. “These are all nervous system issues—it’s not just dementia like people think. The nervous system does a lot other than that and affects your quality of life.”
People in the poor mental health class were just as likely to have a disease, such as heart disease or hypertension, as the average American but were also more likely to become incapacitated or die within five years.
“The biggest thing here was depressive symptoms, and by that I don’t mean clinical depression,” McClintock said, adding anxiety was another key attribute of this class. “It’s not just, ‘Oh, I’m depressed.’ It’s feeling depressed and the physical indicators of that and health behaviors, like eating and sleeping.”
Move Toward Comprehensive View, Treatment of Health
Based on their findings, McClintock says there should be a shift in how people look at health and aging to the “mosaic” or “constellation” of physical health, health behaviors, psychological health, sensory abilities, neuroimmune function and mobility.
“Right now we have a medical system of specialists, and increasingly it becomes important, our data shows, to find a doctor who’s trained in dealing with multiple diseases and multiple conditions,” she said. “Look for getting health care from a team who talks to each other, not just a team spilling out from a center. … But a team that can weigh the relative strengths and weaknesses in making critical decisions.”
This could make a difference in terms of the treatment options a patient seeks for cancer, for example.
“If [a doctor] knows you’re in the robust obese class and you had cancer, you may choose a more aggressive form of treatment than if you’re in the multi-morbidity (least healthy) class. Not only because it’s hard to tolerate [a more aggressive treatment] but also because of the quality of your remaining life,” she said.
McClintock also stressed the importance of addressing mental and social health. People classified as having poor mental health tended to be the sickest and very isolated.
“Having a social network is key to health,” she said. “It’s important to be part of social organizations, like a church, volunteering, participating in a hobby or interest group and building social ties with people so you can talk about things that are really important.
“These are all things that are associated with these six patterns of health and are key to [experiencing] aging that is as pleasant and robust as possible for as long as possible.”
Follow Kristen Thometz on Twitter: @kristenthometz
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