Pollution + Stress = Disease; 1 + 1 = 4

Lindsey Konkel has just published an outstanding article on Environmental Health News.  Here is an excerpt:

When doctors told Wanda Ford her 2-year-old son had lead poisoning, she never suspected that the back yard in her low-income neighborhood was the likely culprit.

Ford knew that exposure to the heavy metal could be dangerous. So when she and her husband moved into the Lower Lincoln Street neighborhood, Ford, then pregnant, took steps to make sure their 100-year-old home was lead-free.

“We never thought to test the soil – my son played in the back yard all the time,” said Ford, whose son is now seven.

It’s long been known that children in poorer neighborhoods like Ford’s are more likely to be exposed to lead, industrial emissions, vehicle exhaust and other contaminants. Now, scientists are beginning to suspect that low-income children aren’t just more exposed – they actually may be more biologically susceptible to them, even at low levels.

A growing body of research suggests that the chronic stressors of poverty may fundamentally alter the way the body reacts to pollutants, especially in young children. Several studies have found that such stress may exacerbate the effects of lead on children’s developing brains, while others reported more asthma symptoms in kids with simultaneous exposure to air pollution and socioeconomic problems.

Everyone experiences stress occasionally; it can improve focus and performance to overcome obstacles at work, during athletic competitions, or in everyday life. But stress also can harm the body.

“When the stress is chronic and the stressors are out of our control, we experience it as a threat rather than a challenge,” said Dr. Rosalind Wright, a physician and epidemiologist at the Harvard School of Public Health. “This type of stress can have negative, lasting effects on key systems in the body. It’s like having the fight or flight response turned on all the time.”

Schools and homes next to refineries and Superfund sites, farm workers drinking toxic water, urban children breathing exhaust from congested streets. Many of these people are living in poverty or with low incomes, and they have to cope with socioeconomic problems as well as high exposure to pollutants. Scientists say living in such areas and facing financial strain, racial issues and high crime rates can wear down the systems responsible for controlling immunity and hormones. Hormones needed for proper brain development may be altered, or the immune system may continually release inflammatory molecules into the blood.

“This may make you more susceptible to everything else around you, including pollution,” said Jane Clougherty, an exposure scientist and epidemiologist at the University of Pittsburgh Graduate School of Public Health.

One + one = four

Stress, when combined with certain pollutants, may produce a much greater health effect than either stress or pollution alone.

“It would be like adding one and one together and getting three or four,” said Dr. Ted Schettler, science director of the Science and Environmental Health Network, a non-profit organization focused on applying science to promote health. “Socioeconomic status may affect underlying biology, making exposure to certain chemicals more adverse for the poorer kid.”

In Worcester, about 40 miles west of Boston, nearly one in five residents lives below poverty level, almost double the Massachusetts average, according to 2010 U.S. Census data. Its median household income is roughly 30 percent lower than the state’s.

Worcester is representative of many old manufacturing towns across the country. “With a decline in manufacturing, you get a decline in certain types of pollution, but you are also left with ongoing problems such as lead contamination in soil, which is typical of a lot of older American towns and cities,” said Katherine Kiel, an environmental economist at the College of the Holy Cross in Worcester. “Low-income housing is often built where property is cheapest. Unfortunately, these areas often have more pollution.”

Socioeconomic stress “may make you more susceptible to everything else around you, including pollution.  –Jane Clougherty, University of PittsburghThe eaves of Ford’s home – one of Worcester’s iconic triple-decker apartment houses – are blackened by soot from trucks and cars. From her front porch, she can see the on-ramp to the interstate highway that bisects the city.

“This feels like a depressed town. There are a lot of neglected, dilapidated places. It’s not very child-friendly,” said Ford, who is not using her real name for fear that her son will be bullied at school about his learning disabilities.

Ford is black, as is roughly 12 percent of Worcester. One small study published last year found that women in Boston who faced racial discrimination and community violence had higher levels of a stress hormone linked to preterm births.

Gang activity and a drug raid at a house nearby have brought community violence close to home. “My husband and I didn’t see it at first when we moved here, but it’s pervasive,” said Ford.

Rates of violent crimes in Worcester are about 17 percent higher than the national average. In 2010, there were roughly 471 assaults, armed robberies and murders per 100,000 inhabitants in Worcester. The national average for that same period was 404 violent crimes per 100,000 people, according to the FBI’s Uniform Crime Reports.

She worries constantly about the safety of her kids. Four of them, all under the age of 15, live at home.

When her son was born in 2004, he seemed healthy. “Looking back, there were signs of developmental delays early on, like he drooled too much, but we didn’t think much of it,” she said.

When he was 2, his doctor found that his blood lead levels were elevated, though they fell below the commonly defined threshold for effects of lead. Ten micrograms per deciliter has traditionally been defined as the harmful level, but recently the Centers for Disease Control and Prevention lowered it to five, recognizing that effects can occur at lower levels.

Synergy between lead and stress

With lead pollution, “the toxicity of lead may be stronger in a child also exposed to the stress of poverty,” said Dr. Robert Wright, a pediatrician and environmental health scientist at the Harvard School of Public Health, and husband of Rosalind Wright.

Lead exposure, which has been linked to reduced IQs, attention problems and aggressive behavior, may be more detrimental to low-income kids than to children in families with higher incomes. Children in Boston began to show reduced IQ at blood lead levels as low as six micrograms per deciliter, while kids from families with more financial resources only began to show cognitive deficits at levels greater than 10, according to one study.

“If this synergy exists between stress and lead, from a biological perspective, it’s plausible this link exists between stress and other neurotoxic pollutants, such as mercury and polychlorinated biphenyls (PCBs) as well,” said Robert Wright.

For years, toxicologist Deborah Cory-Slechta of University of Rochester and her colleagues have studied the combined effects of lead and stressful conditions on lab rats. Lead plus stress had effects on their learning ability and brains that did not occur with either of those factors alone, according to their research.

Researchers are trying to tease apart why chronic stress may make some pollutants more harmful. Both human and animal studies suggest that it can throw key systems of the body out of whack. At a young age, it may create hormonal shifts that permanently alter the way the body responds to future stresses, including chemical exposures. It also may weaken the immune system or trigger inflammation.

“Inflammation is central to a lot of chronic diseases we worry about today,” including respiratory diseases such as asthma, Clougherty said.

In one study, young male laboratory rats put under chronic stress showed a rapid, shallow breathing pattern when inhaling polluted air – unlike rats exposed only to the pollution.

The researchers created a stressful environment by placing the young male rat in the home cage of an older, dominant male twice a week. The stressed rats had higher levels of molecules associated with inflammation in their blood.

Also, in East Boston, children who were previously exposed to community violence were more likely to show signs of asthma when breathing traffic-related air pollution than children in less violent neighborhoods. “This suggests a model where stress impacts the child’s susceptibility to pollution,” said Clougherty.

In addition to asthma, this may make low-income children more predisposed to diabetes, heart disease and even dementia later in life.

Kids living with violence also may experience more wear and tear on their DNA, damage that has been linked to disease later in life, according to a Duke University study published in April.

Susceptibility starts in the womb. Exposure to stress and pollution before birth and during early childhood may be particularly harmful because “both may alter development of the brain, lungs and nervous system during these critical periods,” said Rosalind Wright.

This raises an important question: Are people protected by policies that just consider their chemical exposures without looking at their living conditions, too? Many scientists think not.

Increased risks due to social status are “a critically important but neglected area within risk assessment, and should be incorporated in the future,” Harvard epidemiologists Joel Schwartz and David Bellinger and Johns Hopkins’ Thomas Glass wrote in a 2011 report.

Schettler said “this new understanding has the potential to change the way we think about interventions for low-income children.”

More.

Fish -> Mercury -> Children -> Stress -> Disease

From Environmental Health News:

A study raises concern about children’s exposure to mercury through fish eating, tying it for the first time to hormone changes that increase chronic stress and associated immune system dysfunction.

The mercury levels measured in the children were well below the levels considered a health risk by the U.S. Environmental Protection Agency.

This new study from Oswego County, New York, finds that higher mercury levels measured in the children’s blood are significantly associated with lower cortisol levels. The hormone cortisol is released in response to stress and is important for metabolism, immune responses and blood pressure. Its levels naturally fluctuate during the day – levels are higher in the morning and lower in the afternoon.

Even lower cortisol levels and responses can result in chronic stress even though stress increases the hormone’s level. The study’s results suggest that mercury exposure at levels commonly seen in fish eating populations may do this. It may act as a chronic stressor and disrupt the stress response. Chronic stress means the body doesn’t relax – cells continually function in high gear and do not return to a normal state. Long-term stress can have many negative health effects such as increased heart disease, more metabolic disorders and lowered immunity.

The findings are in line with prior studies in people and fish. The toxic metal increased inflammation in miners exposed to mercury. Animal studies find reduced cortisol levels in mercury-contaminated fish after capture stress.

Fish consumption is a major source both of beneficial omega-3 fatty acids and toxic mercury. Omega-3s benefit health by protecting against heart disease. Mercury is potentially harmful because it affects the brain and nervous system in children. Although there are fish advisories in many states, it is still uncertain whether the benefit of eating fish outweighs the potential harm in children.

To address the pros and cons of fish eating in children, the researchers examined 100 children from 9 to 11 years old in New York State. Parents reported children’s fish consumption, which was categorized as eating or not in the analysis. Blood mercury levels, blood lipids, cortisol in saliva and inflammation markers were measured. Blood lipids indicate future heart disease risk; cortisol reflects changes of stress response; and inflammation markers indicate immune response differences.

Fish eaters had higher HDL – or so called good cholesterol – related to lower heart disease risk, than non-fish eaters. However, the fish eaters also had much higher – almost three times higher – mercury levels than non-fish eaters (1.1 and 0.4 microgram per liter, respectively).

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Toxic Stress – an Upstream Cause of Disease

From Harvard Public Health Review:

Could a sunny outlook mean fewer colds and less heart disease?

Do hope and curiosity somehow protect against hypertension, diabetes, and respiratory tract infections?

Do happier people live longer—and, if so, why?

These are the kinds of questions that researchers are asking as they explore a new—and sometimes controversial—avenue of public health: documenting and understanding the link between positive emotions and good health.

A vast scientific literature has detailed how negative emotions harm the body. Serious, sustained stress or fear can alter biological systems in a way that, over time, adds up to “wear and tear” and, eventually, illnesses such as heart disease, stroke, and diabetes. Chronic anger and anxiety can disrupt cardiac function by changing the heart’s electrical stability, hastening atherosclerosis, and increasing systemic inflammation.

Jack P. Shonkoff, Julius B. Richmond FAMRI Professor of Child Health and Development at HSPH and at the Harvard Graduate School of Education, and Professor of Pediatrics at Harvard Medical School, explains that early childhood “toxic stress”—the sustained activation of the body’s stress response system resulting from such early life experiences as chronic neglect, exposure to violence, or living alone with a parent suffering severe mental illness—has harmful effects on the brain and other organ systems. Among these effects is a hair-trigger physiological response to stress, which can lead to a faster heart rate, higher blood pressure, and a jump in stress hormones.

FOCUSING ON THE POSITIVE
“But negative emotions are only one-half of the equation,” says Laura Kubzansky, HSPH associate professor of society, human development, and health. “It looks like there is a benefit of positive mental health that goes beyond the fact that you’re not depressed. What that is is still a mystery. But when we understand the set of processes involved, we will have much more insight into how health works.”

Kubzansky is at the forefront of such research. In a 2007 study that followed more than 6,000 men and women aged 25 to 74 for 20 years, for example, she found that emotional vitality—a sense of enthusiasm, of hopefulness, of engagement in life, and the ability to face life’s stresses with emotional balance—appears to reduce the risk of coronary heart disease. The protective effect was distinct and measurable, even when taking into account such wholesome behaviors as not smoking and regular exercise.

Among dozens of published papers, Kubzansky has shown that children who are able to stay focused on a task and have a more positive outlook at age 7 report better general health and fewer illnesses 30 years later. She has found that optimism cuts the risk of coronary heart disease by half.

Kubzansky’s methods illustrate the creativity needed to do research at the novel intersection of experimental psychology and public health. In the emotional vitality study, for example, she used information that had originally been collected in the massive National Health and Nutrition Examination Survey, or NHANES, an ongoing program that assesses the health and nutritional status of adults and children in the United States. Starting with the NHANES measure known as the “General Well-Being Schedule,” Kubzansky crafted an adaptation that instead reflected emotional vitality, and then scientifically validated her new measure. Her research has also drawn on preexisting data from the Veterans Administration Normative Aging Study, the National Collaborative Perinatal Project, and other decades-long prospective studies.

In essence, Kubzansky is leveraging gold-standard epidemiological methods to ask new public health questions. “I’m being opportunistic,” she says. “I don’t want to wait 30 years for an answer.”

Poverty – The Tradeoff between Mental and Physical Health

From University of Michigan:

When people are under chronic stress, they tend to smoke, drink, use drugs and overeat to help cope with stress. These behaviors trigger a biological cascade that helps prevent depression, but they also contribute to a host of physical problems that eventually contribute to early death.

That is the claim of University of Michigan social scientist James S. Jackson and colleagues in an article published in the May 2010 issue of the American Journal of Public Health. The theory helps explain a long-time epidemiological puzzle: why African Americans have worse physical health than whites but better psychiatric health.

“People engage in bad habits for functional reasons, not because of weak character or ignorance,” says Jackson, director of the U-M Institute for Social Research. “Over the life course, coping strategies that are effective in ‘preserving’ the mental health of blacks may work in concert with social, economic and environmental inequalities to produce physical health disparities in middle age and later life.”

In an analysis of survey data, obtained from the same people at two points in time, Jackson and colleagues find evidence for their theory. The relationship between stressful life events and depression varies by the level of unhealthy behaviors. But the direction of that relationship is strikingly different for blacks and whites.

Controlling for the extent of stressful life events a person has experienced, unhealthy behaviors seem to protect against depression in African Americans but lead to higher levels of depression in whites.

“Many black Americans live in chronically precarious and difficult environments,” says Jackson. “These environments produce stressful living conditions, and often the most easily accessible options for addressing stress are various unhealthy behaviors. These behaviors may alleviate stress through the same mechanisms that are believed to contribute to some mental disorders—the hypothalamic-pituitary-adrenal cortical axis and related biological systems.”

Since negative health behaviors such as smoking, drinking alcohol, drug use and overeating (especially comfort foods) also have direct and debilitating effects on physical health, these behaviors—along with the difficult living conditions that give rise to them—contribute to the disparities in mortality and physical health problems between black and white populations.

These disparities in physical health and mortality are greatest at middle age and beyond, Jackson says. Why?

“At younger ages, blacks are able to employ a variety of strategies that, when combined with the more robust physical health of youth, effectively mask the cascade to the negative health effects,” Jackson said. “But as people get older, they tend to reduce stress more often by engaging in bad habits.”

Black women show heightened rates of obesity over the life course, he points out. In fact, by the time they are in their 40s, 60 percent of African American women are obese.

“How can it be that 60 percent of the population has a character flaw?” Jackson asks. “Overeating is an effective, early, well-learned response to chronic environmental stressors that only strengthens over the life course. In contrast, for a variety of social and cultural reasons, black American men’s coping choices are different.

“Early in life, they tend to be physically active and athletic, which produces the stress-lowering hormone dopamine. But in middle age, physical deterioration reduces the viability and effectiveness of this way of coping with stress, and black men turn in increasing numbers to unhealthy coping behaviors, showing increased rates of smoking, drinking and illicit drug use.”

Racial disparities in physical illnesses and mortality are not really a result of race at all, Jackson says. Instead, they are a result of how people live their lives, the composition of their lives. These disparities are not just a function of socioeconomic status, but of a wide range of conditions including the accretion of micro insults that people are exposed to over the years.

“You can’t really study physical health without looking at people’s mental health and really their whole lives,” he said. “The most effective way to address an important source of physical health disparities is to reduce environmentally produced stressors—both those related to race and those that are not. We need to improve living conditions, create good job opportunities, eliminate poverty and improve the quality of inner-city urban life.

“Paradoxically, the lack of attention to these conditions contributes to the use of unhealthy coping behaviors by people living in poor conditions. Although these unhealthy coping behaviors contribute to lower rates of mental disorder, over the life course they play a significant role in leading to higher rates of physical health problems and earlier mortality than is found in the general population.”

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Upstream Effects of Inequality

From TEDTalks:

We feel instinctively that societies with huge income gaps are somehow going wrong. Richard Wilkinson charts the hard data on economic inequality, and shows what gets worse when rich and poor are too far apart: real effects on health, lifespan, even such basic values as trust.

Stress-Pollution Interactions

From Environmental Health News:

Cumulative risk assessment posits that multiple agents work together to induce disease and that multiple stressors therefore must be considered in order to gain a true understanding of why adverse health effects occur.  Now a small but growing number of scientists are pushing the envelope by investigating whether chronic psychological stress might be one of those factors, enhancing a child’s vulnerability to certain chemical exposures and contributing to effects that later show up as asthma, neurodevelopmental disorders, cardiovascular disease, obesity, cancer, and other problems. These researchers are also starting to identify biomarkers that may shed light on the mechanisms by which psychological stress acts on a child’s developing immune system and brain to modify or enhance the response to certain pollution exposures such as
traffic-related air pollutants and lead.

“We really don’t know how broadly such interactions may occur across chemicals. They are much more likely to occur when the chemical itself acts directly upon stress systems,” says Deborah Cory-Slechta, a professor of environmental medicine at the University of Rochester School of Medicine & Dentistry.

“We know some chemicals that interact with stress, such as lead exposure, but we don’t know which others do.”

Observations of links between stress and disease date back to at least the twelfth century, when the philosopher Maimonides cited emotional upset as a factor in asthma. But proving such links poses a significant challenge, says Malcolm P. Cutchin, a professor at the School of Medicine of the University of North Carolina at Chapel Hill. “Much has been hypothesized about the linkages, but we are just now beginning to tease out relationships and understand the processes,” Cutchin says. As researchers have learned more about techniques that can identify chemical and stress exposures in the human body, they have begun to apply techniques to estimate how people respond to stress and how that response, if it goes awry, can facilitate the development of diseases.

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Mental Health and Climate Change

From the Sydney Morning Herald:

RATES of mental illnesses including depression and post-traumatic stress will increase as a result of climate change, a report to be released today says.

The paper, prepared for the Climate Institute, says loss of social cohesion in the wake of severe weather events related to climate change could be linked to increased rates of anxiety, depression, post-traumatic stress and substance abuse.

As many as one in five people reported ”emotional injury, stress and despair” in the wake of these events.

The report, A Climate of Suffering: The Real Cost of Living with Inaction on Climate Change, called the past 15 years a ”preview of life under unrestrained global warming”.

”While cyclones, drought, bushfires and floods are all a normal part of Australian life, there is no doubt our climate is changing,” the report says.

”For instance, the intensity and frequency of bushfires is greater. This is a ‘new normal’, for which the past provides little guidance …

”Moreover, recent conditions are entirely consistent with the best scientific predictions: as the world warms so the weather becomes wilder, with big consequences for people’s health and well-being.”

The paper suggests a possible link between Australia’s recent decade-long drought and climate change. It points to a breakdown of social cohesion caused by loss of work and associated stability, adding that the suicide rate in rural communities rose by 8 per cent.

The report also looks at mental health in the aftermath of major weather events possibly linked to climate change.

It shows that one in 10 primary school children reported symptoms of post-traumatic stress disorder in the wake of cyclone Larry in 2006. More than one in 10 reported symptoms more than three months after the cyclone.

”There’s really clear evidence around severe weather events,” the executive director of the Brain and Mind Research Institute, Professor Ian Hickie, said.

”We’re now more sophisticated in understanding the mental health effects and these effects are one of the major factors.

”What we have seriously underestimated is the effects on social cohesion. That is very hard to rebuild and they are critical to the mental health of an individual.”

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From TheClimateInstitute.

Stress and Pollution

From Reuters:

Children living in high-stress households are more vulnerable to lung damage from traffic pollution than children whose parents are less stressed out, according to the results of a new study.

“It makes sense,” said Dr. Jane Clougherty from the University of Pittsburgh, who was not involved in this study. “The bodily wear and tear induced by…stress could make the individual more susceptible to the effects of traffic-related air pollution.”

The researchers took measurements of several indicators of lung function in nearly 1,400 children living in southern California.

They also predicted the amount of traffic pollutants the children were exposed to by sampling almost 1,000 different sites around the area. In particular the researchers were looking for nitrogen oxides, which are formed when fuel is burned. Nitrogen oxides can damage lung tissue and make asthma worse, they explain in an article in the American Journal of Respiratory and Critical Care Medicine.

Six years earlier, the children’s parents had filled out a questionnaire about their level of stress. The questions asked how often they felt able to handle personal problems or felt in control, for instance.

Air pollution levels varied widely depending on where the children lived, from six parts per billion of nitrogen oxides to 101 parts per billion.

For kids from high-stress homes, when the average amount of nitrogen oxides in the air went up by 22 parts per billion, their lung function got roughly five percent worse.

That same increase in pollutants around a child whose parents had a low level of stress made no difference to their lung function, however.

Dr. Talat Islam from the University of Southern California, the lead author of the study, said he expected that stress would lead to a bigger effect of pollution on kids, but he was surprised that increased air pollution had no effect on the kids from low-stress homes.

“We see the whole effect of traffic-related air pollution in those children who were exposed to higher stress,” Islam told Reuters Health.

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Image source.

Hidden Costs of Oil: Mental Health

From Time:

When the Exxon Valdez ran ashore in Prince William Sound in 1989, the immediate focus was on the damage that millions of gallons of oil might do to the pristine Alaskan waters. And, indeed, the toll was terrible: an estimated 250,000 birds died because of the spill, and the Sound’s productive fisheries took years to fully recover from the pollution. Even today, you can find leftover oil on the rocky islands of the Sound.

Yet there was another long-lasting impact from the spill: the mental health of the nearby community. Alcoholism, domestic abuse, stress and divorce all skyrocketed in the wake of the disaster, and the wounds were slow to heal. A recent study found that levels of stress among those Alaskans who were involved in litigation over the oil spill were as high in 2009 as they were in 1991. The oil spill was, as sociologist Steven Picou termed it, a “constantly renewing disaster.”

Now, a year after the Gulf oil spill, there are concerns that even though the ecological effects of the accident aren’t as great as initially feared, residents along the coast might suffer the same fate their predecessors in Alaska did. A forthcoming study of Gulf Coast residents affected by the spill — conducted by Picou, Liesel Ritchie of the University of Colorado and Duane Gill of Oklahoma State University — found that one-fifth of respondents qualified as being under severe stress, and one-fourth were in moderate stress. Those numbers are comparable to stress levels in the Prince William Sound area a few months after the Valdez spill.

Those Gulf Coasters who had a connection to local resources, like fisherman, were even more likely to experience high levels of stress, as were people with low income levels and low levels of education. And if the trends observed in Alaska hold true for the Gulf Coast, significant levels of stress could continue for far longer. “Given the social scientific evidence amassed over the years in Prince William Sound, Alaska, we can only conclude that social disruption and psychological stress will characterize residents of Gulf Coast communities for decades to come,” the authors write.

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Stories from the Gulf

From NRDCflix:

NRDC partnered with StoryCorps and Bridge the Gulf to record, share, and preserve the stories and experiences of those living through the BP oil disaster. Find out more at http://www.nrdc.org/storycorps.