Common origin behind major childhood allergies

Several major childhood allergies may all stem from the community of bacteria living in our gut, according to a new study led by researchers at the University of British Columbia and BC Children's Hospital.

The research, published in Nature Communications, identifies gut microbiome features and early life influences that are associated with children developing any of four common allergies -- eczema, asthma, food allergy and/or hay fever. The findings could lead to methods of predicting whether a child will develop allergies, and ways to prevent them from developing at all.

"We're seeing more and more children and families seeking help at the emergency department due to allergies," said Dr. Stuart Turvey, professor in the department of pediatrics at UBC and an investigator at BC Children's Hospital Research Institute, and co-senior author on the study. "Hundreds of millions of children worldwide suffer from allergies, including one in three children in Canada, and it's important to understand why this is happening and how it can be prevented."

The study is one of the first to examine four distinct school-aged pediatric allergies at once. While these allergic diseases each have unique symptoms, the Turvey lab was curious whether they might have a common origin linked to the infant gut microbiota composition.

"These are technically different diagnoses, each with their own list of symptoms, so most researchers tend to study them individually," says Dr. Charisse Petersen, co-senior author on the paper and postdoctoral fellow in the Turvey lab. "But when you look at what is going wrong at a cellular level, they actually have a lot in common."

For the study, researchers examined clinical assessments from 1,115 children who were tracked from birth to age five. Roughly half of the children (523) had no evidence of allergies at any time, while more than half (592) were diagnosed with one or more allergic disorders by an expert physician. The researchers evaluated the children's microbiomes from stool samples collected at clinical visits at three months and one year of age.

The stool samples revealed a bacterial signature that was associated with the children developing any of the four allergies by five years of age. The bacterial signature is a hallmark of dysbiosis, or an imbalanced gut microbiota, that likely resulted in a compromised intestinal lining and an elevated inflammatory response within the gut.

"Typically, our bodies tolerate the millions of bacteria living in our guts because they do so many good things for our health. Some of the ways we tolerate them are by keeping a strong barrier between them and our immune cells and by limiting inflammatory signals that would call those immune cells into action," says Courtney Hoskinson, a PhD candidate at UBC and first author on the paper. "We found a common breakdown in these mechanisms in babies prior to the development of allergies."

Many factors can shape the infant gut microbiota, including diet, how we are born, where we live, and our exposure to antibiotics. For example, antibiotics may wipe out sensitive bacteria, while breastfeeding tends to replenish and provide necessary food for bacteria in the infant gut. The researchers examined how these types of influences affected the balance of gut microbiota and the development of allergies.

"There are a lot of potential insights from this robust analysis," says Dr. Turvey. "From these data we can see that factors such as antibiotic usage in the first year of life are more likely to result in later allergic disorders, while breastfeeding for the first six months is protective. This was universal to all the allergic disorders we studied."

Now the researchers hope to leverage the findings to inform treatments that correct an imbalanced gut microbiota and could potentially prevent allergies from developing.

"Developing therapies that change these interactions during infancy may therefore prevent the development of all sorts of allergic diseases in childhood, which often last a lifetime," says Dr. Turvey.

The research is part of the Canadian Healthy Infant Longitudinal Development (CHILD) Cohort Study that recruited families through BC Children's Hospital and BC Women's Hospital + Health Centre and other pediatric hospitals across Canada. Since launching in 2008, the team of Canadian researchers has tracked the health, growth and environments of kids from birth and made important discoveries about how asthma and allergies develop.

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Hunter-gatherer childhoods may offer clues to improving education and wellbeing in developed countries

Hunter-gatherers can help us understand the conditions that children may be psychologically adapted to because we lived as hunter-gatherers for 95% of our evolutionary history. And paying greater attention to hunter-gatherer childhoods may help economically developed countries improve education and wellbeing.

Published today in the Journal of Child Psychology and Psychiatry, a new study by Dr Nikhil Chaudhary, an evolutionary anthropologist at the University of Cambridge, and Dr Annie Swanepoel, a child psychiatrist, calls for new research into child mental health in hunter-gatherer societies. They explore the possibility that some common aspects of hunter-gatherer childhoods could help families in economically developed countries. Eventually, hunter-gatherer behaviours could inform 'experimental intervention trials' in homes, schools and nurseries.

The authors acknowledge that children living in hunter-gatherer societies live in very different environments and circumstances than those in developed countries. They also stress that hunter-gatherer children invariably face many difficulties that are not experienced in developed countries and, therefore, caution that these childhoods should not be idealised.

Drawing on his own observations of the BaYaka people in Congo and the extensive research of anthropologists studying other hunter-gatherer societies, Dr Chaudhary highlights major differences in the ways in which hunter-gatherer children are cared for compared to their peers in developed countries. He stresses that "contemporary hunter-gatherers must not be thought of as 'living fossils', and while their ways of life may offer some clues about our prehistory, they are still very much modern populations each with a unique cultural and demographic history."

Physical contact and attentiveness

Despite increasing uptake of baby carriers and baby massage in developed countries, levels of physical contact with infants remain far higher in hunter-gatherer societies. In Botswana, for instance, 10-20 week old !Kung infants are in physical contact with someone for around 90% of daylight hours, and almost 100% of crying bouts are responded to, almost always with comforting or nursing -- scolding is extremely rare.

The study points out that this exceptionally attentive childcare is made possible because of the major role played by non-parental caregivers, or 'alloparents', which is far rarer in developed countries.

Non-parental caregivers

In many hunter-gatherer societies, alloparents provide almost half of a child's care. A previous study found that in the DRC, Efe infants have 14 alloparents a day by the time they are 18 weeks old, and are passed between caregivers eight times an hour.

Dr Chaudhary said: "Parents now have much less childcare support from their familial and social networks than would likely have been the case during most of our evolutionary history. Such differences seem likely to create the kind of evolutionary mismatches that could be harmful to both caregivers and children."

"The availability of other caregivers can reduce the negative impacts of stress within the nuclear family, and the risk of maternal depression, which has knock-on effects for child wellbeing and cognitive development."

The study emphasises that alloparenting is a core human adaptation, contradicting 'intensive mothering' narratives which emphasise that mothers should use their maternal instincts to manage childcare alone. Dr Chaudhary and Dr Swanepoel write that 'such narratives can lead to maternal exhaustion and have dangerous consequences'.

Care-giving ratios

The study points out that communal living in hunter-gatherer societies results in a very high ratio of available caregivers to infants/toddlers, which can even exceed 10:1.

This contrasts starkly with the nuclear family unit, and even more so with nursery settings, in developed countries. According to the UK's Department of Education regulations, nurseries require ratios of 1 carer to 3 children aged under 2 years, or 1 carer to 4 children aged 2-3.

Dr Chaudhary said: "Almost all day, hunter-gatherer infants and toddlers have a capable caregiver within a couple of metres of them. From the infant's perspective, that proximity and responsiveness, is very different from what is experienced in many nursery settings in the UK."

"If that ratio is stretched even thinner, we need to consider the possibility that this could have impacts on children's wellbeing."

Children providing care and mixed-age active learning

In hunter-gatherer societies, children play a significantly bigger role in providing care to infants and toddlers than is the case in developed countries. In some communities they begin providing some childcare from the age of four and are capable of sensitive caregiving; and it is common to see older, but still pre-adolescent children looking after infants.

By contrast, the NSPCC in the UK recommends that when leaving pre-adolescent children at home, babysitters should be in their late teens at least.

Dr Chaudhary said: "In developed countries, children are busy with schooling and may have less opportunity to develop caregiving competence. However, we should at least explore the possibility that older siblings could play a greater role in supporting their parents, which might also enhance their own social development."

The study also points out that instructive teaching is rare in hunter-gatherer societies and that infants primarily learn via observation and imitation. From around the age of two, hunter-gatherer children spend large portions of the day in mixed-age (2-16) 'playgroups' without adult supervision. There, they learn from one another, acquiring skills and knowledge collaboratively via highly active play practice and exploration.

Learning and play are two sides of the same coin, which contrasts with the lesson-time / play-time dichotomy of schooling in the UK and other developed countries.

Dr Chaudhary and Dr Swanepoel note that "Classroom schooling is often at odds with the modes of learning typical of human evolutionary history." The study acknowledges that children living in hunter-gather societies live in very different environments and circumstances than those in developed countries:

"Foraging skills are very different to those required to make a living in market-economies, and classroom teaching is certainly necessary to learn the latter. But children may possess certain psychological learning adaptations that can be practically harnessed in some aspects of their schooling. When peer and active learning can be incorporated, they have been shown to improve motivation and performance, and reduce stress." The authors also highlight that physical activity interventions have been shown to aid performance among students diagnosed with ADHD.

The study calls for more research into children's mental health in hunter-gatherer societies to test whether the hypothesised evolutionary mismatches actually exist. If they do, such insights could then be used to direct experimental intervention trials in developed countries.

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Positive childhood experiences of blue spaces linked to better adult well-being

New research based on data from 18 countries concludes that adults with better mental health are more likely to report having spent time playing in and around coastal and inland waters, such as rivers and lakes (also known collectively as blue spaces) as children. The finding was replicated in each of the countries studied.

Mounting evidence shows that spending time in and around green spaces such as parks and woodlands in adulthood is associated with stress reduction and better mental health. However, we know far less about the benefits of blue spaces, or the role childhood contact has in these relationships in later life.

Data came from the BlueHealth International Survey (BIS), a cross-sectional survey co-ordinated by the University of Exeter's European Centre for Environment and Human Health. The current analysis used data from over 15,000 people across 14 European Countries and 4 other non-European countries/regions (Hong Kong, Canada, Australia and California).

Respondents were asked to recall their blue space experiences between the ages of 0-16 years including how local they were, how often they visited them, and how comfortable their parents/guardians were with them playing in these settings, as well as more recent contact with green and blue spaces over the last four weeks, and mental health over the last two weeks.

The research, published in the Journal of Environmental Psychology, found that individuals who recalled more childhood blue space experiences tended to place greater intrinsic value on natural settings in general, and to visit them more often as adults -- each of which, in turn, were associated with better mental wellbeing in adulthood.

Valeria Vitale, Lead author and PhD Candidate at Sapienza University of Rome, said: "In the context of an increasingly technological and industrialized world, it's important to understand how childhood nature experiences relate to wellbeing in later life.

"Our findings suggest that building familiarity and confidence in and around blue spaces during childhood may stimulate an inherent joy of nature and encourage people to seek out recreational nature experiences, with beneficial consequences for adult mental health."

Dr Leanne Martin, Co-author and Postdoctoral Research Associate at the University of Exeter's European Centre for Environment and Human Health, said: "Water settings can be dangerous for children, and parents are right to be cautious. This research suggests though that supporting children to feel comfortable in these settings and developing skills such as swimming at an early age can have previously unrecognised life-long benefits."

Dr Mathew White, Co-author and Senior Scientist at the University of Vienna, said: "The current study is adding to our growing awareness of the need for urban planners and local bodies responsible for managing our green and blue spaces to provide safe, accessible access to natural settings for the healthy mental and physical development of our children.

"If our findings are supported by longitudinal research that tracks people's exposures over the entire life-course, it would suggest that further work, policies and initiatives encouraging more blue space experiences during childhood may be a viable way to support the mental health of future generations."

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Positive parenting can reduce the risk that children develop obesity

New research from Penn State found that children with positive, early interactions with their care givers -- characterized by warmth, responsiveness, and a sitmulating home environment -- were at reduced risk of childhood obesity.

"A lot of the discussion around childhood obesity and other health risks focuses on identifying and studying the exposure to risk," said Brandi Rollins, assistant research professor of biobehavioral health. "We took a strength-based approach in our analysis. We found that a supportive family and environment early in a child's life may outweigh some of the cumulative risk factors that children can face."

The study, "Family Psychosocial Assets, Child Behavioral Regulation, and Obesity," recently appeared in the journal Pediatrics. In the article, Rollins and Lori Francis, associate professor of biobehavioral health, analyzed data from over 1,000 mother-child pairs and found that children's early exposures to family psychosocial assets -- including a quality home environment, emotional warmth from the mother, and a child's ability to self-regulate -- reduced the risk of developing childhood obesity.

Encouragingly, these factors were protective even when children faced familial risks for obesity, including poverty, maternal depression, or residence in a single-parent home.

"Research on parenting has shown that these types of family assets influence children's behavior, academic success, career, and -- not surprisingly -- health," Rollins said. "It is significant that these factors also protect against childhood obesity because the family assets we studied are not food or diet-specific at all. It is heartening to know that, by providing a loving, safe environment, we can reduce the risk that children will develop obesity."

Severe obesity

Children are deemed to have obesity when their body mass indices (BMIs) are greater than 95% of other children their age and gender. There is a great deal of variance, however, in the BMIs of children who exceed the obesity threshold. Children whose BMI is 20% higher than the obesity threshold are considered to have severe obesity.

The researchers found that children who had early-onset severe obesity did not face greater levels of family risk than children who were not obese. Children with severe obesity, however, did have fewer family assets than children who were not obese or who displayed moderate levels of obesity. More research is needed to understand which factors contribute to the development of severe obesity and which factors reduce the risk.

"Though the findings on severe obesity may seem discouraging, they offer some hope," Rollins explained. "Some risk factors, like household poverty, can be very difficult to change. Assets, on the other hand, may be easier to build. People can learn to parent responsively. It is encouraging that parenting really matters, that family matters."

What parents can do

This work is based on research in parenting and child development. Responsive parenting, one of the family assets measured in the study, involves responding to children in a timely, sensitive, and age-appropriate manner based on the child's presenting needs. Researchers in Penn State's Center for Childhood Obesity Research are also exploring how responsive parenting can reduce the risk of childhood obesity.

This study focused on childhood obesity, but the researchers said that parents may improve many outcomes for their children by learning responsive-parenting skills. Knowledge of responsive-parenting skills, however, may not lead directly to implementing those skills in the home.

"No one can read a pamphlet about cars and suddenly expect to drive," said Rollins. "Driving is a skill that requires education and practice. The same is true of responsive parenting.

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