Author Archives: Catherine Zandonella

Model anticipates ecological impacts of human responses to climate (Conservation Biology)

A Princeton University research team has created a readily transferable method for conservation planners trying to anticipate how agriculture will be affected by such adaptations. The tested their model by studying wheat and maize production in South Africa. (Image source: WWS)

A Princeton University research team has created a readily transferable method for conservation planners trying to anticipate how agriculture will be affected by such adaptations. The tested their model by studying wheat and maize production in South Africa. (Image source: WWS)

By B. Rose Huber, Woodrow Wilson School of Public and International Affairs

Throughout history, humans have responded to climate.

Take, for example, the Mayans, who, throughout the eighth and 10th centuries, were forced to move away from their major ceremonial centers after a series of multi-year droughts, bringing about agricultural expansion in Mesoamerica, and a clearing of forests. Much later, in the late 20th century, frequent droughts caused the people of Burkina Faso in West Africa to migrate from the dry north to the wetter south where they have transformed forests to croplands and cut the nation’s area of natural vegetation in half.

Such land transformations, while necessary to ensure future crop productivity, can themselves have large ecological impacts, but few studies have examined their effects. To that end, a Princeton University research team has created a model to evaluate how a human response to climate change may alter the agricultural utility of land. The study, featured in Conservation Biology, provides a readily transferable method for conservation planners trying to anticipate how agriculture will be affected by such adaptations.

“Humans can transform an ecosystem much more rapidly and completely than it can be altered by shifting temperature and precipitation patterns,” said Lyndon Estes, lead author and associate research scholar in the Woodrow Wilson School of International and Public Affairs. “This model provides an initial approach for understanding how agricultural land-use might shift under climate change, and therefore which currently natural areas might be converted to farming.”

Under the direction of faculty members Michael Oppenheimer and David Wilcove, both from the Wilson School’s Program in Science, Technology and Policy, and with the help of visiting student research collaborator Lydie-Line Paroz from ETH Zurich and colleagues from several other institutions, Estes studied South Africa, an area projected to be vulnerable to climate change where wheat and maize are the dominant crops.

Before determining how climate change could impact the crops, the team first needed to determine which areas have been or might be farmed for maize and wheat. They created a land-use model based on an area’s potential crop output and simulated how much of each crop was grown from 1979 to 1999 – the two decades for which historical weather data was available. They also calculated the ruggedness of each area of land, which is related to the cost of farming it. Taking all factors into account, the model provides an estimate of whether the land is likely to be profitable or unprofitable for farming.

To investigate any climate-change impacts, the team then examined the production of wheat and maize under 36 different climate-response scenarios. Many possible future climates were taken into account as well as how the crops might respond to rising levels of carbon dioxide. Based on their land-use model, the researchers calculated how the climate-induced productivity changes alter a land’s agricultural utility. In their analysis, they included only conservation lands – current nature reserves and those that South African conservation officials plan to acquire – that contained land suitable for growing one of the two crops either currently or in the future. However, Estes said the model could be adapted to assess whether land under other types of uses (besides conservation) are likely to be profitable or unprofitable for future farming.

They found that most conservation lands currently have low agricultural utility because of their rugged terrain, which makes them difficult to farm, and that they are likely to stay that way under future climate-change scenarios. The researchers did pinpoint several areas that could become more valuable for farming in the future, putting them at greater risk of conversion. However, some areas were predicted to decrease value for farming, which could make them easier to protect and conserve.

“While studying the direct response of species to climatic shifts is important, it’s only one piece of a complicated puzzle. A big part of that puzzle relates to how humans will react, and history suggests you don’t need much to trigger a change in the way land is used that has a fairly long-lasting impact. ” said Estes. “We hope that conservation planners can use this approach to start thinking about human climate change adaptation and how it will affect areas needing protection.”

Other researchers involved in the study include: Lydie-Line Paroz, Swiss Federal Institute of Technology; Bethany A. Bradley, University of Massachusetts; Jonathan Green, STEP; David G. Hole, Conservation International; Stephen Holness, Centre for African Conservation Ecology; and Guy Ziv, University of Leeds.

The work was funded by the Princeton Environmental Institute‘s Grand Challenges Program.

Read the abstract.

Estes LD, Paroz LL, Bradley BA, Green JM, Hole DG, Holness S, Ziv G, Oppenheimer MG, Wilcove DS. Using Changes in Agricultural Utility to Quantify Future Climate-Induced Risk to Conservation Conservation Biology (2013). First published online Dec. 26, 2013.

Death of an adult son increases depressive symptoms in mothers, but not fathers (Social Science and Medicine)

Sad mother picture

A study by researchers at Princeton and Georgetown Universities found that Taiwanese mothers – but not fathers – experience depressive symptoms after an adult son’s death, while the death of a daughter had no such effect on either parent.

By B. Rose Huber, Woodrow Wilson School of Public and International Affairs

Mothers – but not fathers – exhibited symptoms of depression and experienced declines in overall health after the death of an adult son, while the death of a daughter had no such effect on either parent, according to one of the first studies to examine the impacts of the death of an adult child on parents aged 65 and older.

In East Asian cultures, an adult son’s role in the family is crucial to the wellbeing and financial stability of his parents, the researchers suggest. Therefore, a traumatic event, like the death of a son, could place quite a strain on elderly parents living in these cultures – particularly women, especially if the deceased son is the eldest or only son.

The researchers, from the Office of Population Research in Princeton University’s Woodrow Wilson School, published their findings in the journal Social Science & Medicine based on data from the Taiwanese Longitudinal Study of Aging, a nationally representative survey designed to assess the health of older people in Taiwan.

“In East Asian cultures like Taiwan, sons hold the primary responsibility for providing financial and instrumental assistance to their elderly parents,” said lead author Chioun Lee, a Princeton postdoctoral research associate. “Older women who have had particularly few educational and occupational opportunities are more likely to rely on their sons for support. Therefore, a traumatic event, like a son’s death, could place quite a strain on a mother’s health.”

Along with study coauthor Noreen Goldman, the Hughes-Rogers Professor of Demography and Public Affairs at WWS, and researchers from Georgetown University, Lee used data collected for the Taiwanese Longitudinal Study of Aging from 1996 to 2007, which included approximately 4,200 participants.

To evaluate parental wellbeing, they used two self-reported measures: one for overall health and another for depressive symptoms. Each respondent’s health was assessed based on the following question: “Regarding your current state of health, do you feel it is excellent, good, average, not so good, or poor?” The items were coded on a one-to-five-point scale with higher scores indicating better health. Past studies have indicated that this measure is a strong predictor of mortality.

Depressive symptoms were measured with an eight-item subset of the Center for Epidemiological Studies Depression Scale, which asks participants to report how often they’ve experienced various situations or feelings in the past week. Possible answers range from “0,” which means rarely or none of the time, to “3,” which is most or all of the time. Higher scores for the eight items indicate more frequent depressive symptoms.

The researchers controlled for parental wellbeing prior to the death of a child and analyzed the data in two stages. First, they tested the extent to which a child’s death affected a parent’s health and then whether that varied by the parent’s sex. Finally, they determined the influence of a deceased child’s sex on parental wellbeing.

They found that women who lost a son scored, on average, 2.4 points higher on levels of depressive symptoms than those who did not lose a child. For men, there were no significant differences. There was no evidence to suggest that either mothers or fathers were significantly affected by depressive symptoms or declines in reports of overall health following the death of a daughter. Lee explains that while finances are a concern, there may be other factors at play.

“I also think that various attributes of deceased children, such as birth order, affective bonds with their parents or cause of death, might influence parental wellbeing,” said Lee, who is a native of Korea and observed son preference and gender inequality throughout her childhood.

According to Goldman, these findings underscore the continued gender inequality in Taiwan.

“Despite large advances in women’s labor market participation and educational attainment in recent years – for example, women in Taiwan are now more likely than men to hold a higher education degree – son preference persists, affecting various aspects of women’s well-being,” Goldman said.

Read the abstract.

Lee, C., et al., Death of a child and parental wellbeing in old age: Evidence from Taiwan, Social Science & Medicine (2013), http://dx.doi.org/10.1016/jsocscimed.2013.08.007

The work was funded by the Demography and Epidemiology Unit of the Division of Behavioral and Social Research at the National Institute on Aging and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

More or less equal? How men factor into the reproductive equation (Gender & Society)

A new study calls attention to the role of men’s behavior and health in reproductive outcomes, such as fetal health, birth defects and childhood diseases. (Image credit: CDC/Amanda Mills)

A new study calls attention to the role of men’s behavior and health in reproductive outcomes, such as fetal health, birth defects and childhood diseases. (Image credit: CDC/Amanda Mills)

By Bess Connolly Martell, Office of Public Affairs and Communications, Yale University

Researchers know a lot about how women’s bodily health affects their fertility, but less is known about how men’s health affects reproductive outcomes. Yale University researcher Rene Almeling and co-author Miranda Waggoner of Princeton University address this discrepancy in an article published Tuesday, Dec. 3, in the journal Gender & Society.

In the period before conception, family health history and current health behaviors matter for women and men alike, say the researchers, adding that more clinical research needs to be done on how men’s bodily health affects their sperm, and in turn, reproductive health outcomes.

“The lack of attention to men in research on reproduction leaves open many important questions, including how men’s reproductive contributions are understood,” say Almeling, an assistant professor of sociology at Yale, and Waggoner, a postdoctoral researcher in the Office of Population Research in the Woodrow Wilson School of Public and International Affairs at Princeton.

The vast majority of medical and social science research on reproduction focuses on women. It wasn’t until recently that scientists began studying the role that men’s behavior and men’s health play in reproductive outcomes, such as fetal health, birth defects and childhood diseases.

The stereotypical association of women with family and men with work has led to a focus on women’s bodies in reproduction, leaving the question of how men’s health contributes to reproduction unanswered.

“What kinds of advice, if any, do men receive about preparing their bodies for reproduction?” ask the researchers. “Men should be empowered with information about how their age, health history and unhealthy behaviors can affect pregnancy outcomes.”

The sperm bank is one of the few places where men’s reproductive health takes center stage, the researchers note. At sperm banks, men are counseled on healthy eating, avoiding stress and reducing alcohol consumption. Not adhering to this advice can and does lead to lower sperm counts, suggesting that this kind of guidance might be more broadly useful for men trying to conceive children with their partners.

There are also associated policy implications. The Affordable Care Act stipulates that women with private insurance are no longer required to pay for preconception health appointments, but excluding men from such coverage continues to obscure their role in reproduction, say Almeling and Waggoner. “Paying attention to how reproductive equations influence policy can suggest new and different avenues for improving public health,” say the sociologists. They add, “Recent public health initiatives devoted to preconception care offer at least the possibility that men’s reproductive contributions will be considered alongside women’s.”

Read the abstract.

Almeling, Rene and Miranda R. Waggoner. More and Less than Equal: How Men Factor in the Reproductive Equation. Gender & Society December 2013 27: 821-842, first published on April 25, 2013 doi:10.1177/0891243213484510.

Both authors received funding from the National Science Foundation (Almeling grant #0602871 and Waggoner grant #1029087), and Miranda Waggoner also received support from the National Institutes of Health (T32 HD007163).

Global effort is needed to keep antibiotics working (Lancet Infectious Diseases)

By Holly Welles, Princeton Environmental Institute

Polar bear

The low antibiotic resistance observed in polar bears on the isolated Arctic archipelago of Svalbard supports the theory that resistance in animals is due to the influence of humans. (Source: Hannes Grobe, Alfred Wegener Institute for Polar and Marine Research)

A global approach is needed to address the unfolding burden of antibiotic resistance, say the authors of a new report, published this week in Lancet Infectious Diseases. The report coincides with the European Antibiotic Awareness Day and the U.S. Centers for Disease Control and Prevention (CDC) “Get Smart About Antibiotics Week.”

The report, compiled by an international group of 26 leading experts in the field, presents a comprehensive look at the growing problem of antibiotic resistance, its major causes and consequences, and identifies key areas in which action is urgently needed.

One area of particular concern is with the connection to the environment.

Ramanan Laxminarayan,

Ramanan Laxminarayan (Photo courtesy of the Princeton Environmental Institute)

“The environment is key in the spread of resistance,” said the report’s lead author, Ramanan Laxminarayan, research scholar at the Princeton Environmental Institute and lecturer in the Department of Economics at Princeton University.

Antibiotic resistance arises when bacteria evolve mechanisms to withstand the drugs which are used to fight infection.  Recent decades have seen vast increases in the use of antibiotics across medicine and agriculture, and in the absence of adequate regulatory controls, treatment guidelines, and patient awareness, this has led to a huge global surge in antibiotic resistance.

“Many drivers of antibiotic consumption are grounded in human medicine.  However, antibiotic use in veterinary medicine and for growth promotion and disease prevention in agriculture, aquaculture, and horticulture is also a major contributing variable,” said Laxminarayan.  “The very low antibiotic resistance observed in polar bears on the isolated Arctic archipelago of Svalbard supports our theory that the higher resistance found in animals living closer to human settlements is rooted in the anthropogenic use of antibiotics.”

The authors call for a bolder intervention outside hospitals and toward an ecological antibiotic stewardship — recommending the development of strategies focused on the control of non-human sources of antibiotics, resistant bacteria, and resistance genes, such as in agriculture and waste water from the pharmaceutical industry.

“For example, waste water treatment facilities can be a hotspot.  The chlorination of drinking water can, in fact, concentrate some antibiotic resistant genes,” said Laxminarayan.  “One of our key recommendations is for increased research on how to reduce and neutralize manmade antibiotic pressure and how to control the resistance gene pool in hotspot environments.”

Read the full report

Citation: Ramanan Laxminarayan, Adriano Duse, Chand Wattal, Anita K.M. Zaidi, Heiman F.L. Wertheim, Nithima Sumpradit, Ericka Vlieghe, Gabriel Levy Hara, Ian M. Gould, Herman Goossens, Christina Greko, Anthony D. So, Maryam Bigdeli, Goran Tomson, Will Woodhouse, Eva Ombaka, Arturo Quizhpe Peralta, Fara Naz Qamar, Fatima Mir, Sam Kariuki, Zulfigar Bhutta, Anthony Coates, Richard Bergstrom, Gerard Wright, Eric D. Brown, Otto Cars, 2013.  Antibiotic Resistance—The Need for Global Solutions. The Lancet Infectious Diseases.

Feeling pleasure at the misfortune of those you envy is biological (The Annals of the New York Academy of Sciences)

Shutter stock

Abstract image courtesy of Shutterstock. By measuring the electrical activity of cheek muscles and associated neural responses, Princeton University researchers show that people are actually biologically responsive to taking pleasure in the pain of others, a reaction known as “Schadenfreude.”

By B. Rose Huber, Woodrow Wilson School of Public and International Affairs

A new study by Princeton University researchers shows that people are actually biologically responsive to taking pleasure in the pain of others, a reaction known as “Schadenfreude.”

Ph.D student Mina Cikara took up the topic of Schadenfreude after she wore a Boston Red Sox hat to a New York Yankees baseball game. Nicknames and vulgarities were among the souvenirs she took home. And, after hearing about the name-calling and heckling her then-PhD student endured, Princeton professor Susan Fiske was compelled to join her in pursuing the phenomenon further, exploring why people fail to empathize with others based on stereotypes.

Through a series of four experiments – one involving the aforementioned sports rivalry – the researchers found that people are actually biologically responsive to taking pleasure in the pain of others, a reaction known as “Schadenfreude.” By measuring the electrical activity of cheek muscles, the researchers show that people smile more when someone they envy experiences misfortune or discomfort. While these findings hold significance for interpersonal relationships, the researchers also cite associated policy implications, such as how other countries view and stereotype the United States especially given that many countries envy the U.S., Fiske said. Their findings were reported in The Annals of the New York Academy of Sciences.

“Jealousy and envy are highly correlated,” said Fiske, coauthor of the study and the Eugene Higgins Professor of Psychology and Public Affairs in the Woodrow Wilson School. “When we ask people on surveys who is envied in American society, they report the same groups: objects of jealousy. This is all very much based on stereotypes. And so, in this study, we sought to better understand who is among these envied groups and whether that envy and jealousy elicits a harmful response.”

“We were interested in the conditions under which people fail to empathize with one another and how, for some of those people, they experience happiness at another’s expense,” said lead author Cikara, now an assistant professor at Carnegie Mellon University. “We wanted to start in a place where people would be willing to express their opinions and willingness to harm more freely, like we see in sports. We asked ourselves: what is it about rivalries that elicit a harmful response? And can we predict who will have this response?”

In the first experiment, the researchers examined participants’ physical responses by monitoring their cheek movements with an electromyogram (EMG), which captures the electrical activity of facial movements when an individual smiles. Participants were shown photographs of individuals associated with different stereotypes: the elderly (pity), students or Americans (pride), drug addicts (disgust) and rich professionals (envy). These images were then paired with everyday events such as: “Won five dollars” (positive) or “Got soaked by a taxi” (negative) or “Went to the bathroom” (neutral). Participants were asked how this would make them feel, and their facial movements were recorded.

“Because people don’t like to report envy of Schadenfreude, this was the best method for gathering such responses. And, in this experiment, we were able to viscerally capture malicious glee,” Fiske said. “We found that people did smile more in response to negative than positive events, but only for groups they envied.”

In their second experiment, the researchers used self-reporting and functional magnetic resonance imaging (fMRI) – which measures blood flow changes associated with brain activity – to determine whether participants were willing to harm certain groups. Participants viewed the same photographs and events as the first study and were asked to rate how they felt on a scale of one to nine (from extremely bad to extremely good). Similar results emerged: Participants felt the worst about positive events and the best about negative events in regards to the rich professionals. Two weeks later, the researchers followed up with an online survey in which the participants were presented a scenario-based game that involved the option to hurt another person, such as through electric shocks in order to spare several others.

“People were willing to hurt an envy target, saying, ‘Yes, let’s shock her,’” Cikara said. “We found that surprising because we weren’t certain participants would self report that. While it’s true that people are generally averse to harming others, the bottom line is that people don’t feel this way all the time.”

Manipulating stereotypes was the goal of the third experiment. Using various scenarios regarding an investment banker as an example, the researchers threw counter-stereotypic information at participants. In one article, the banker was himself, employed and status quo. In another, he was advising clients pro-bono (eliciting pride). In the next, he was using his work bonuses to buy drugs (disgust) and, finally, he was unemployed but still dressing to go to work (pity). Again, the findings matched earlier experiments – participants rated the articles associated with disgust and envy with less warmth than the pride or pity scenarios.

“This experiment shows that the dimensions predicting envy are high status and competition, and, when you move those around, the envy goes away. This is consistent with the story about who gets envied and why. A lot of it is tied into money because that’s an easy thing to look at,” said Fiske.

In the final experiment, the researchers used Cikara’s experience – a game between the Boston Red Sox and New York Yankees. Both groups of fans were prescreened for “intense fandom.” Participants were again monitored through fMRI and self-reports after watching a series of plays in which opponents struck out, scored runs or made fantastic plays. As predicted, participants reported experiencing more pleasure during positive outcomes for their team.

When a third neutral team – the Baltimore Orioles – was thrown into the mix, the fans reported little to no reaction to positive or negative events and did not wish to cause Orioles fans harm. But they were happy when their rival team lost to the Orioles, showing pure Schadenfreude, said Fiske. An online survey completed by participants two weeks later showed that both groups of fans were more likely to heckle, insult, threaten or hit a rival fan while watching the plays.

“We used a sporting event because it’s something you can bottle,” said Fiske. “Rabid fans are passionate about it, and we were looking for an intergroup phenomenon that reaches people where they live. This is certainly it. But it’s important to remember that this study isn’t just about sports teams. It’s about intergroup rivals of more consequence.”

Fiske thinks of the study as a simulation or model of group envy or harm.

“In our larger model of stereotypes, we find that when things go smoothly, people go along to get along with these envied groups. It’s when the chips are down that these groups become real targets of Schadenfreude.”

In terms of policy implications, Fiske and Cikara agree there are many.

“Around the world, the American government is seen as high status and competent but not necessarily as a group sharing other people’s or countries’ goals. So, as far as other people are concerned, we’re the world’s bullies, and we have data that show that,” said Fiske. “And so, if we want to work with another country, it’s not the respect we’re lacking; it’s the trust. We need to remember that these stereotypes really affect how we enter other settings.”

“A lack of empathy is not always pathological. It’s a human response, and not everyone experiences this, but a significant portion does,” Cikara said. “We need to remember this in terms of everyday situations. If you think about the way workplaces and organizations are set up, for example, it raises an interesting question: Is competition the best way to get your employees to produce? It’s possible, in some circumstances, that competition is good. In other ways, people might be preoccupied with bringing other people down, and that’s not what an organization wants.”

Funding for the work was provided by the Russell Sage Foundation, the Princeton Neuroscience Institute, Princeton’s Center for Human Values, WWS’s Joint Degree Program in Social Policy and the Charlotte Elizabeth Procter Fellowship (awarded to Cikara by Princeton University).

Read the abstract.

Mina Cikara and Susan T. Fiske. Their pain, our pleasure: stereotype content and schadenfreude. Annals of the New York Academy of Sciences. 2013. Vol. 1299 Sociability, Responsibility, and Criminality: From Lab to Law. Pages v–x, 1–100. Article first published online: 24 SEP 2013. DOI: 10.1111/nyas.12179

When scaling the quantum slopes, veer for the straight path (Physical Review A)

Research image

Princeton University researchers found that the “landscape” for quantum control (above) — a representation of quantum mechanics that allows the dynamics of atoms and molecules to be manipulated — can be unexpectedly simple, which could help scientists realize the next generation of technology by harnessing atoms and molecules to create small but incredibly powerful devices. Scientists achieve quantum control by finding the ideal radiation field (top of the graphic) that leads to the desired response from the system. Like a mountain hiker, a scientist can take a difficult, twisting path that requires frequent stops to evaluate the next step (right path). Or, they can opt for a straighter trail that cuts directly to the summit (left path). The researchers provide in their paper an algorithm that scientists can use to identify the starting point of the straight path to their desired quantum field. (Image courtesy of Arun Nanduri)

By Morgan Kelly, Office of Communications

Like any task, there is an easy and a hard way to control atoms and molecules as quantum systems, which are driven by tailored radiation fields. More efficient methods for manipulating quantum systems could help scientists realize the next generation of technology by harnessing atoms and molecules to create small but incredibly powerful devices such as molecular electronics or quantum computers.

Of course, controlling quantum systems is as painstaking as it sounds, and requires scientists to discover the ideal radiation field that leads to the desired response from the system. Scientists know that reaching that state of quantum nirvana can be a long and expensive slog, but Princeton University researchers have found that the process might be more straightforward than previously thought.

The researchers report in the journal Physical Review A that quantum-control “landscapes” — the path of a system’s response from the initial field to the final desired field — appears to be unexpectedly simple. Although still a mountain of a task, finding a good control radiation field turns out to be very much like climbing a mountain, and scientists need only choose the right path. Like a hiker, a scientist can take a difficult, twisting path that requires frequent stops to evaluate which step to take next. Or, as the Princeton researchers show, they can opt for a straighter trail that cuts directly to the summit.

The researchers observe in their paper that these fast tracks toward the desired control field actually exist, and are scattered all over the landscape. They provide an algorithm that scientists can use to identify the starting point of the straight path to their desired quantum field.

The existence of nearly straight paths to reach the best quantum control was surprising because the landscapes were assumed to be serpentine, explained first author Arun Nanduri, who received his bachelor’s degree in physics from Princeton in 2013 and is working in the laboratory of Herschel Rabitz, Princeton’s Charles Phelps Smyth ’16 *17 Professor of Chemistry.

“We found that not only can you always climb to the top, but you can climb along a simple path to the top,” Nanduri said. “If we could consistently identify where these paths are located, a scientist could efficiently climb the landscape. Looking around for the next good step along an unknown path takes great effort. However, starting along a straight path requires you to look around once, and you can keep walking forward with your eyes closed, as it were.”

Following a straighter path could be a far more efficient way of achieving control of atoms and molecules for a host of applications, including manipulating chemical reactions and operating quantum computers, Nanduri said. The source of much scientific excitement, quantum computers would use “qubits” that can be entangled to potentially give them enormous storage and computational capacities far beyond the capabilities of today’s digital computers.

If the Princeton research helps scientists quickly and easily find the control fields they need, it could also allow them to carry out improved measurements of quantum systems and design new ones, Nanduri said.

“We don’t know if our discovery will directly lead to futuristic quantum devices, but this finding should spur renewed research,” Nanduri said. “If straight paths to good quantum control solutions can be routinely found, it would be remarkable.”

Read the abstract.

Nanduri, Arun, Ashley Donovan, Tak-San Ho, Herschel Rabitz. 2013. Exploring quantum control landscape structure. Physical Review A. Article published: Sept. 30, 2013. DOI: 10.1103/PhysRevA.88.033425

The work was funded by the Program in Plasma Science and Technology at Princeton University, the Army Research Office, and the U.S. Department of Energy.

Small declines in agility, facial features may predict risk of dying (Epidemiology)

Photo source: Shutter Stock

Photo source: Shutter Stock

By B. Rose Huber, Woodrow Wilson School of Public and International Affairs

A new study from Princeton University shows that health assessments made by medically untrained interviewers may predict the mortality of individuals better than those made by physicians or the individuals themselves.

Features like forehead wrinkles and lack of agility may reflect a person’s overall health and risk of dying, according to recent health research. But do physicians consider such details when assessing patients’ overall health and functioning?

In a survey of approximately 1,200 Taiwanese participants, Princeton University researchers found that interviewers — who were not health professionals but were trained to administer the survey — provided health assessments that were related to a survey participant’s risk of dying, in part because they were attuned to facial expressions, responsiveness and overall agility.

The researchers report in the journal Epidemiology that these assessments were even more accurate predictors of dying than assessments made by physicians or even the individuals themselves. The findings show that survey interviewers, who typically spend a fair amount of time observing participants, can glean important information regarding participants’ health through thorough observations.

“Your face and body reveal a lot about your life. We speculate that a lot of information about a person’s health is reflected in their face, movements, speech and functioning, as well as in the information explicitly collected during interviews,” said Noreen Goldman, Hughes-Rogers Professor of Demography and Public Affairs in the Woodrow Wilson School.

Together with lead author of the paper, Princeton Ph.D. candidate Megan Todd, Goldman analyzed data collected by the Social Environment and Biomarkers of Aging Study (SEBAS). This study was designed by Goldman and co-investigator Maxine Weinstein at Georgetown University to evaluate the linkages among the social environment, stress and health. Beginning in 2000, SEBAS conducted extensive home interviews, collected biological specimens and administered medical examinations with middle-aged and older adults in Taiwan. Goldman and Todd used the 2006 wave of this study, which included both interviewer and physician assessments, for their analysis. They also included death registration data through 2011 to ascertain the survival status of those interviewed.

The survey used in the study included detailed questions regarding participants’ health conditions and social environment. Participants’ physical functioning was evaluated through tasks that determined, for example, their walking speed and grip strength. Health assessments were elicited from participants, interviewers and physicians on identical five-point scales by asking “Regarding your/the respondent’s current state of health, do you feel it is excellent (5), good (4), average (3), not so good (2) or poor (1)?”

Participants answered this question near the beginning of the interview, before other health questions were asked. Interviewers assessed the participants’ health at the end of the survey, after administering the questionnaire and evaluating participants’ performance on a set of tasks, such as walking a short distance and getting up and down from a chair. And physicians — who were hired by the study and were not the participants’ primary care physicians — provided their assessments after physical exams and reviews of the participants’ medical histories. (Study investigators did not provide special guidance about how to rate overall health to any group.)

In order to understand the many variables that go into predicting mortality, Goldman and Todd factored into their statistical models such socio-demographic variables as gender, place of residence, education, marital status, and participation in social activities. They also considered chronic conditions, psychological wellbeing (such as depressive symptoms) and physical functioning to account for a fuller picture of health.

“Mortality is easy to measure because we have death records indicating when a person has died,” Goldman said. “Overall health, on the other hand, is very complicated to measure but obviously very important for addressing health policy issues.”

Two unexpected results emerged from Goldman and Todd’s analysis. The first: physicians’ ratings proved to be weak predictors of survival. “The physicians performed a medical exam equivalent to an annual physical exam, plus an abdominal ultrasound; they have specialized knowledge regarding health conditions,” Goldman explained. “Given access to such information, we anticipated stronger, more accurate predictions of death,” she said. “These results call into question previous studies’ assumptions that physicians’ ‘objective health’ ratings are superior to ‘subjective’ ratings provided by the survey participants themselves.”

In a second surprising finding, the team found that interviewers’ ratings were considerably more powerful for predicting mortality than self-ratings. This is likely, Goldman said, because interviewers considered respondents’ movements, appearance and responsiveness in addition to the detailed health information gathered during the interviews. Also, Goldman posits, interviewer ratings are probably less affected by bias than self-reports.

“The ‘self-rated health’ question is religiously used by health researchers and social scientists, and, although it has been shown to predict mortality, it suffers from many biases. People use it because it’s easy and simple,” Goldman continued. “But the problem with self-rated health is that we have no idea what reference group the respondent is using when evaluating his or her own health. Different ethnic and racial groups respond differently as do varying socioeconomic groups. We need other simple ways to rate individual health instead of relying so heavily on self-rated health.”

One way, Goldman suggests, is by including interviewer ratings in surveys along with self-ratings: “This is a straightforward and cost-free addition to a questionnaire that is likely to improve our measurement of health in any population,” Goldman said.

The paper, “Do Interviewer and Physician Health Ratings Predict Mortality? A Comparison with Self-Rated Health,” first appeared online in Epidemology in August 2013. The article also will be featured in the November print edition. The research was conducted with the assistance of colleagues at Princeton’s Office of Population Research, Georgetown University and the Bureau of Health Promotion in the Taiwan Department of Health.

Read the abstract.

Todd MA, Goldman N. Do interviewer and physician health ratings predict mortality?: a comparison with self-rated health. Epidemiology. 2013 Nov;24(6):913-20. doi: 10.1097/EDE.0b013e3182a713a8.