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Early Environments on Health Trajectories

Early-Life Psychological Stress and Long-Term Health Effects

Inflammation is thought to be a key pathway linking childhood stress with health problems, yet the available research has not been comprehensively evaluated to further understand this relationship. In Psychological Bulletin, IPR health psychologists Edith Chen and Greg Miller, graduate research assistant Phoebe Lam, and former IPR post-doctoral fellow Jessica Chiang of Georgetown University seek to answer three questions: How the relationship between childhood stress and inflammation changes over the lifespan, if certain childhood stressors affect inflammation differently, and which inflammation components are associated with childhood stress. Their meta-analysis examined 187 studies from the last two decades that investigated the relationship between childhood stress and inflammation. The researchers find that as people age, the relationship between childhood stress and inflammation gets stronger, suggesting that effects of early stress grow over time. They also find that children exposed to severe or chronic psychological stress, such as living in a violent neighborhood or having a clinically depressed parent, had higher levels of inflammation. The meta-analysis found that different components of inflammation are similarly associated with stress. These findings better establish the link between inflammation and stress-induced health issues and identify inflammation as a key target to relieve childhood stress effects. These findings can help determine what interventions, especially psychological ones, to provide, who might benefit from them, and if certain stressful experiences should be addressed. Edith Chen is the John D. and Catherine T. MacArthur Professor of Psychology and Greg Miller is the Louis W. Menk Professor of Psychology.

Childhood Infections and Biological Aging 

Human life expectancy has doubled over the last 200 years, but we do not really understand why. Though researchers have studied how infants’ environments affect their health as they age, the role infectious diseases play in the pace of biological aging is unclear. In the American Journal of Human Biology, IPR anthropologists Thomas McDade and Christopher Kuzawa, along with their colleagues, investigate this connection. Using data from the Cebu Longitudinal Health and Nutrition Survey in the Philippines, they examine 1,450 participants born in 1983–84 who were 20–21 years old in 2005 when blood samples were taken from which DNA was extracted and analyzed. Additionally, they also had health history data for their first two years from in-home interviews. Three markers, which indicate epigenetic—or biological—age, were measured in the DNA samples. The researchers’ analysis showed that individuals who had more infections by age 2 had a younger biological age in adulthood. The authors call for more research to investigate the immune mechanisms affected by early exposure to infections and how they might influence aging.  McDade is Carlos Montezuma Professor of Anthropology, and Kuzawa is John D. MacArthur Professor of Anthropology. 

Legacies of Apartheid and Psychiatric Illness 

Apartheid has had lasting consequences in South Africa, including widespread poverty, racial discrimination, and class inequality. In his study published in The Journal of Child Psychology and Psychiatry, IPR anthropologist Christopher Kuzawa and his colleagues investigate whether prenatal stress experienced due to intergenerational trauma, meaning the effects that the trauma experienced by one generation has on subsequent generations, under apartheid impacted the mental health of children born as apartheid ended. The researchers used a longitudinal study among 304 pregnant women enrolled in 1990 in the city of Soweto-Johannesburg, a major center of violence during apartheid. Researchers questioned the women to determine their level of social adversity during their pregnancy. When their children reached ages 17 to 18, their mental health was assessed using a General Health Questionnaire (GHQ), which is a psychological screener that assesses mental health based on four scales. The researchers find that while prenatal stress caused by apartheid did not correlate with a direct increase in mental health issues in adolescents, it did cause them to be more vulnerable to mental health issues, especially if they experienced household adversity. Additionally, their research established the effects of maternal age, social support, and past household adversity on the mental health of children at age 17 or 18, which also played a key role in determining the relative psychiatric health of children. The researchers suggest that the effects of South African apartheid must be addressed to reduce the risk of mental health issues. Kuzawa is the John D. MacArthur Professor of Anthropology.

Low Socioeconomic Status and Responses to Rewards and Losses

In trying to understand the long-term consequences of poverty, researchers have hypothesized that economic scarcity may lead people to seek immediate rewards at the expense of pursuing long-term goals. In the Journal of Cognitive Neuroscience, IPR psychologist Robin Nusslock, IPR health psychologist Greg Miller, and their colleague study this hypothesis using MRI. To conduct the study, 172 adolescents between the ages of 12 to 15 living in the Chicago area attended an initial session with a parent or guardian who completed an interview about their household finances. The participants were 40.1% White, 30.8% Black, and 29.1% Hispanic. The participants underwent an MRI while performing a passive avoidance task. The adolescents completed 24 trials, choosing to press a button or not press a button when presented with four objects that would allow them to earn or lose money. The researchers find that participants with a lower income-to-poverty (IPR) ratio had worse performance on the passive avoidance task and were less likely to distinguish between reward and loss information. Their analyses identified several brain regions, including attention networks, the parietal cortex, and the ventromedial prefrontal cortex, whose functions contributed to these variations in performance. These findings support the hypothesis that variations in distinguishing between long-term rewards and small, immediate rewards may be a link between poverty and life outcomes. Future research should include longitudinal studies looking at the developmental implications of poverty and how economic interventions may change the brain’s ability to process rewards. Miller is Louis W. Menk Professor of Psychology.

How Childhood Adversity Is Linked with Health Among Potential Parents

Is childhood adversity linked with health risks during pregnancy and childbirth? In Women’s Health Issues, IPR social demographer  IPR social demographer Christine Percheski, community health scholar and IPR associate Joe Feinglass, and their colleagues examine the connection between adverse childhood experiences (ACEs) and health conditions that could increase pregnancy and birth complications. ACEs include childhood abuse, exposure to family violence, parental incarceration, and other traumatic experiences. The researchers analyzed ACEs and health histories of thousands of women and men aged 18–39, using survey data from the 2019 Behavioral Risk Factor Surveillance System. They show that women had higher overall ACE scores than men, largely driven by reported sexual abuse. Almost one in four young women reported experiencing four or more ACEs. After accounting for demographic characteristics, young women with four or more ACEs were more likely to be obese, have high blood pressure, and develop diabetes than young women with no ACEs. They were also almost four times as likely to report a history of depression and more than twice as likely to report fair or poor health. The findings suggest a need for a trauma-informed approach to supportive services for mothers and mothers-to-be with ACEs, as well as the need for ‘social infrastructure’ policies that can disrupt the intergenerational transmission of childhood adversity.

Understanding and Improving Nutrition for Pregnancy 

Growing evidence shows that the nutrition a baby receives while still in the womb affects its health as an adult in many ways. This has vital implications for public policy to improve pregnant women’s health and diet. Nutrition includes both micronutrients—vitamins and minerals—and macronutrients, or fat, carbohydrates, and protein. Adding vitamin supplements during pregnancy can increase birth weight, a measure of newborn health. But what about macronutrients? IPR anthropologist Christopher Kuzawa, Zaneta Thayer (PhD 2013) of Dartmouth College, and former IPR postdoctoral fellow Julienne Rutherford of the University of Illinois at Chicago propose a new model to understand how nutrition is delivered to the fetus during pregnancy. In Evolution, Medicine, & Public Health, they argue that their Maternal Nutritional Buffering Model explains why other changes to pregnant women’s diets have limited effects on fetal development and birth weight. Using an evolutionary perspective, the authors point out that the mother’s body protects the growing fetus from both nutritional ups and downs, tempering the benefits of short-term diet interventions. The researchers propose that the most effective way to improve babies’ health both at birth and as future adults is to improve their mothers’ nutrition far earlier before they become pregnant. Kuzawa is the John D. MacArthur Professor of Anthropology. 

Evictions Rates and Adverse Pregnancy Outcomes

Housing instability, especially eviction, can have a negative impact on pregnancy outcomes due to financial, social, and emotional stress. Former IPR post-doctoral fellow Alexa Freedman, IPR health psychologist Greg Miller, professor of obstetrics and gynecology and IPR associate Ann Borders, and their colleagues investigate the connection between neighborhood eviction rates and adverse pregnancy outcomes in a study published in the Journal of Epidemiology and Community Health. The researchers looked at delivery records from 76,938 single births between March 2008 and March 2018 at a Chicago hospital. They used the addresses of individuals to identify neighborhoods, and determined the eviction rates of those neighborhoods using data from Princeton University’s Eviction Lab. The study finds that mothers who lived in neighborhoods with the highest eviction rates were 1.17 times as likely to deliver their babies pre-term and were 1.13 times more likely to deliver a baby with low birth weight compared to those living in neighborhoods with the lowest eviction rates. These results suggest that mothers living in neighborhoods with higher eviction rates are more likely to deliver pre-term. The connection was strongest for individuals with a lower median household income. The researchers argue that it is important to be aware of the connection between eviction rates and pregnancy outcomes in order to inform policy that could improve tenant protections and living conditions in low-income areas. Miller is the Louis W. Menk Professor of Psychology.

Pre-Pregnancy Maternal Mental Health Impact on Children

What impact do pre-pregnancy posttraumatic stress disorder (PTSD) and symptoms of depression among mothers have on the cortisol levels of their young children? Cortisol levels are indicative of stress, and flatter daily cortisol slopes point to adverse mental, physical, and behavioral outcomes for children. In Developmental Psychobiology, IPR developmental psychologist Emma Adam and her colleagues study 85 mother-child pairs participating in research of the Community Child Health Network (CCHN). Before becoming pregnant, women rated their levels of stress and mental health using the PTSD Checklist–Civilian Version, the Perceived Stress Scale, and Postnatal Depression Scale. Then, their children provided saliva samples at the ages of four and five years, which were used to measure cortisol levels three times across the day. The study found that PTSD symptoms in mothers were significantly associated with cortisol levels in their children that were flatter than normal, a pattern which is associated with poor mental and physical outcomes. However, mothers’ pre-pregnancy symptoms of depression and stress did not have an apparent effect on the cortisol levels of their children. Additionally, cortisol awakening responses (CARs) were tested for in children, but were found to have no correlation with pre-pregnancy mental health for mothers. Based on these findings, the researchers suggest women be screened for PTSD allowing for treatment prior to the start of pregnancy to improve maternal and child mental health. Adam is Edwina S. Tarry Professor of Human Development and Social Policy.

The Impact of JFK’s Assassination on Birth Outcomes

The association between stressful events during pregnancy and worrying birth outcomes, such as premature birth and low birthweight, has been widely studied. In Maternal and Child Health Journal, IPR researchers postdoctoral fellow Alexa Freedman, health psychologist Greg Miller, obstetrician and gynecologist Ann Borders, and their colleagues explore whether–and in what ways—the shock of the assassination of President John F. Kennedy (JFK) affected births to women pregnant on November 22, 1963. The study employs data from the Collaborative Perinatal Project, 1959–65, which followed pregnant participants at 12 U.S. sites over time. The researchers analyzed the births of over 30,200 pregnant participants, about 5,800 of whom were pregnant at the assassination. They determine that only those in their first trimester showed any measurable effects. They find an increased risk—a hazard ratio of 1.17, or about one-sixth more risk—of preterm birth for babies born to women in their first trimester when JKF was killed. They also detect a link to a slight reduction in birthweight for children born to those women. Additionally, the researchers compared the birth outcomes of over 1,100 pairs of siblings born to women in the study who had a child prior to the assassination and then were pregnant when the assassination occurred, seeing similar effects. The researchers did not find a connection between first trimester stress and inflammation of the placenta, which they had considered a possible mechanism in the adverse birth outcomes. The research supports the association between stress exposure early in pregnancy and preterm birth. Miller is the Louis W. Menk Professor of Psychology.

The Association Between Childhood Abuse and Cardiovascular Risk

Experiences early in life such as childhood abuse can potentially lead to increased cardiovascular disease risk factors in adulthood. In the Journal of the American Heart Association, pediatrician and IPR associate Nia Heard-Garris and her colleagues examine the association between exposure to abuse in childhood and four major risk factors for heart disease, including obesity, type 2 diabetes, high blood pressure, and hyperlipidemia, or high cholesterol and other fats in the blood, and whether growing up in a nurturing household affects the relationship. The researchers explored data from the ongoing Coronary Artery Risk Development in Young Adults (CARDIA) study, which follows over 5,000 Black and White adults from four cities who were recruited from 1985­–86. Participants, who were aged 33–45, completed a questionnaire about their exposure to physical or psychological abuse and their home environment as a child, which aimed to compare associations between abuse, nurturing relationships, household organization and cardiovascular disease risk factors. The results showed that White men who experienced occasional or frequent childhood abuse had a higher risk of developing type 2 diabetes than those who experienced no abuse. For White men and women, the risk for hyperlipidemia was low for those in a non-abusive household. However, the risk was higher for White women in dysfunctional or abusive households. The patterns remain similar for Black men: Those who experienced occasional or frequent abuse had a lower risk of hyperlipidemia if they lived in a well-managed household. Among differing race, gender, and household organization, abuse in childhood was not associated with an increased risk of other cardiovascular disease factors, such as obesity and hypertension. These results suggest that there is a connection between childhood abuse and cardiovascular risk factors that differs by race, gender, and household organization. More research is necessary to better understand these differences.

Early Origins of Socioeconomic Inequalities in Chronic Inflammation

The United States is characterized by persistent and widening social inequities in many adult health outcomes, and researchers have begun to ask how these outcomes trace back to childhood. In Social Science & Medicine, IPR anthropologist Thomas McDade and IPR postdoctoral fellow Stephanie Koning consider the extent to which socioeconomic inequalities in adult health may be influenced by experiences earlier in life. Utilizing data from the National Longitudinal Study of Adolescent to Adult Health of 7,610 young adults aged 24­–32 years, the researchers documented a strong relationship between  lower socioeconomic status (SES) and higher levels of chronic inflammation in adulthood, as measured by C-reactive protein. They also examined the participants’ birth weight and duration of breastfeeding in infancy, and investigated whether they could account for the SES gradient in chronic inflammation.  They find that increasing the time a mother breastfeeds to three or more months reduces the SES gradient in inflammation  by more than 80%. The results indicate that environments early in infancy are important determinants of chronic inflammation in adulthood, and that breastfeeding three months or longer could reduce SES-based inequalities in cardiometabolic disease, which result in part from higher levels of chronic inflammation. The researchers suggest that social policies addressing structural barriers to extended breastfeeding, such as paid family leave, could have the greatest impact in reducing inequalities in breastfeeding. McDade is Carlos Montezuma Professor of Anthropology.

How Therapists Can Help Patients With Unexplained Illness

Functional Neurological Disorders (FNDs) are surprisingly common, yet poorly understood neurological conditions which are determined to be “incompatible” with known diseases. In a 2020 article for Social Science & Medicine, IPR anthropologist Rebecca Seligman and her postdoctoral fellow, Northwestern anthropologist Maddalena Canna, who is the paper’s lead author, argue that a cultural analysis is required to better understand and help people with FNDs. Seligman and Canna analyze three case studies, focusing on one particular kind of FND, a disorder known as PNES (Psychogenic-Non-Epileptic Seizure). They describe three key ways in which FNDs are mediated by culture: how patients use existing cultural meanings and representations to mediate and describe their own experience; the forms of expression available and strategies for dealing with trauma in a given context; and the judgment and social stigma patients may face due to their symptoms. Seligman and Canna conclude that given this complex system of cultural factors, effective therapies should be based on constructing a shared set of meanings between patient and therapist. They recommend therapists and patients de-emphasize the need to come to an objective “truth” about the disease, in favor of a willingness to view it through the other’s perspective. The researchers note that making space for patients’ definition of their disorder leaves open the possibility of future medical diagnoses that may explain the roots and causes of FNDs.

Disproportionate School Punishment of Black Students and Life Outcomes

Racial disparities exist in school disciplinary practices, with Black students being more likely to receive punishment than White students. In Psychological Science, IPR health psychologists Edith Chen and Greg Miller, along with their colleagues, study the relationship between racial inequalities in the punishment of Black students and their long-term outcomes. The researchers used data from an 18-year longitudinal study of 261 Black young adults—91 male and 170 female—from working- poor households in rural Georgia. The researchers collected assessments of academic outcomes, mental health, and physical health (including blood samples) from participants at age 27.  The researchers also examined high school discipline records to calculate the punishment rates for Black and White students at each of the high schools attended by students in the sample. They find in schools with higher rates of punishment for Black relative to White students, the Black youth in the sample with high self-control in early adolescence had higher academic orientation in late adolescence that eventually led to higher academic attainment, higher income, and better mental health in adulthood. But these students also had worse insulin resistance in adulthood, which is a predictor of cardiometabolic diseases. These results suggest that achieving success in the face of racial inequalities, such as disproportionate school punishment, may come at a cost to the physical health of Black youth. The researchers argue that there are psychological characteristics that can help individuals to stay resilient even in the face of inequality-related adversities. Chen is the John D. and Catherine T. MacArthur Professor of Psychology. Miller is the Louis W. Menk Professor of Psychology.