wheezing

ECHO-funded Research Finds Higher Asthma Rates Among Black and Hispanic Children Regardless of Neighborhood Income or Density

Posted on by Jodi Snare

A new ECHO study found that although there is a correlation between childhood asthma and being born into a densely populated or lower-income neighborhood, Black and Hispanic children had consistently higher rates of asthma than White children, even in wealthier neighborhoods.

The study, led by ECHO investigators, Dr. Antonella Zanobetti, Harvard T.H Chan School of Public Health, Department of Environmental Health, and Dr. Patrick H. Ryan, Cincinnati Children’s Hospital Medical Center, included data from 5,809 children born over four decades throughout the United States, providing important insight into how racial and ethnic health inequities may cause children to develop wheezing – a symptom involving whistling breathing sounds due to narrowed airways – and asthma.

Of the 5,809 children studied, 46% reported wheezing prior to age 2 and 26% reported persistent wheeze through age 11. Diagnosis of asthma by age 11 varied by cohort, with an overall median prevalence of 25%. Children in neighborhoods with higher population density, and with more families with lower incomes and living below the poverty level, experienced more asthma and early and persistent wheezing. Black and Hispanic children remained at higher risk for asthma than White children, even in neighborhoods with more resources.

Researchers used questionnaires and interviews to collect information such as wheezing and asthma occurrence, medical history, and demographics from participating families over many years. Each child’s home address was matched to U.S. Census tract data for the decade closest to their birth year. Researchers examined the relationship between incidence of wheezing and asthma with children’s race and ethnicity, their mother’s education level and smoking habits, and socioeconomic conditions of the neighborhood in which they were born.

“Neighborhood- and individual-level characteristics and their root causes should be considered as sources of respiratory health inequities,” Dr. Zanobetti said. “Reducing these inequities requires identifying and repairing differences between and within neighborhoods to create equal access to healthy living conditions.”

This research, titled “Childhood Asthma Incidence, Early and Persistent Wheeze, and Neighborhood Socioeconomic Factors in the ECHO/CREW Consortium,” is published in JAMA Pediatrics.

Read the Research Summary.

ECHO Cohort Examines the Association between Genetic Variants and Wheezing Patterns in Young Children

Posted on by Jodi Snare
Brian Hallmark, PhD
Lead Author
University of Arizona

Wheezing is often an early indicator of childhood asthma. While there are several studies looking at patterns of childhood wheezing as well as studies investigating the association between genetic variants and childhood asthma, research is lacking on the direct association between wheezing patterns and genetic variants. To fill this gap, members of ECHO Children’s Respiratory Research and Environment Workgroup (CREW) explored the effect of chromosome 17q12-21 variants, which have been previously linked to childhood asthma, on patterns of wheezing in African American and European American children across the US.

Data collection lasted several years as ECHO CREW sites used questionnaires and interviews to collect information from children and their parents. The researchers harmonized data from the different sites in order to group children based on when and how often they wheezed from birth to 11 years old. Sites also collected DNA samples from most of the children, and researchers analyzed those samples for the presence of nine different small gene changes, also known as single nucleotide polymorphisms (SNPs), at the 17q12-21 chromosome locus. Using statistical techniques, the team then identified different wheezing patterns and measured their association with each of the genetic variants.

Overall, four wheezing patterns were identified among participants:

  1. Infrequent—few wheezing episodes only in the first three years
  2. Transient—some wheezing in first three years, then less, and gone by around six years
  3. Late-onset—little wheezing in the first few years and then gradually occurs more often
  4. Persistent—many wheezing episodes over the first 11 years of life.

These patterns are similar to with the wheezing patterns identified in previous studies that used data collected from other birth cohorts.

Researchers also found that a little more than half of the children experienced wheezing before three years old, and 62% wheezed within the first 10 years of life. Early childhood wheezing often starts due to a viral infection, such as the common cold. Additionally, some children who are diagnosed with asthma may experience transient wheezing patterns that will not last beyond pre-school.

This study was also the first to investigate how genetic variation relates to wheezing patterns in African American children. African American children were statistically more likely than European American children to experience persistent wheezing. While most of the SNPs were associated with transient, late-onset, and persistent wheezing patterns in European American children, only two SNPs were associated with these wheezing patterns in both European American and African American children. One of these SNPs interrupts production of a protein that may be involved in protecting the body from viral infection in the upper airways.

“Asthma is complicated, and susceptible children exposed to hazards such as viruses, allergens, and pollution have more risk of having episodes of wheeze in the preschool years,” said lead author Brian Hallmark, PhD, from the University of Arizona. “Some genetic variations put children at higher risk. The more we understand how asthma develops, the better we can identify and help children at risk and find ways to prevent asthma.”

Not only is this study the first to examine genetic variation and wheezing patterns in African American children, it is also the first to find evidence that genetic variants associated with childhood asthma are also associated with all early life wheezing patterns. These results are found consistently in children from different cities and those born in different decades. In the future, the team will focus on possible associations between children’s insulin levels, genetic variations, and the development of asthma in childhood.

Read the research summary.

ECHO Study Identifies Genetic Underpinnings of Wheezing Patterns Linked to Asthma

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ECHO Study Identifies Genetic Underpinnings of Wheezing Patterns Linked to Asthma

Author(s): Brian Hallmark, et al.

 

Who sponsored this study?

This research was supported by the Environmental influences on Child Health Outcomes (ECHO) program, Office of The Director, National Institutes of Health under Award Number 5UH3 OD023282.

 

What were the study results?

Four wheezing patterns were seen among the children: (1) infrequent—few wheezing episodes in the first three years then none after that; (2) transient—some wheezing in first few years then fewer and gone by around age six; (3) late onset—little wheezing in the first few years then slowly happens more often; (4) persistent—many wheezing episodes over the first 11 years.

About half of children experience wheezing before three years old, and 62% wheezed in the first 10 years of life. The wheezing may start because of a viral infection (like the common cold). Many children  only wheeze as preschoolers. AA children were more likely than European American (EA) children to have persistent wheezing.

Several small gene changes were connected to transient, late onset, and persistent wheezing in EA children, but for both AA and EA children, only two specific small gene changes were connected with a greater likelihood of the child wheezing after the first three years.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

 

What was the study's impact?

For the first time, it is reported that genetic changes associated with childhood asthma are also associated with all wheezing patterns in young children. These wheezing patterns were found consistently in children located in different cities and born in different decades.

Wheezing in young children is often a result of common respiratory viruses that affect breathing. These findings, together with what we know about the genes associated with asthma, suggest that some of these small gene changes may be connected to a higher risk of colds and other viral airway infections that trigger wheezing in small children.

This study also highlights the importance of including multiple race/ancestry groups in genetic studies to understand how small changes in genes are connected to different health outcomes in diverse groups.

 

Why was this study needed?

Previous studies have shown that many children wheeze during the first few years of life—some later stop, while others can develop ongoing asthma. Other children do not wheeze during early life but still develop asthma later during childhood. Understanding where these patterns come from may shed light on how asthma begins and help doctors identify children who might need help earlier. Other studies identified small changes in specific genes that could be responsible for some cases of childhood asthma. This study tried to find possible connections between those small gene changes and different wheezing patterns in children. This is also the first study that looks at how small genetic changes may relate to specific patterns of wheezing in African American (AA) children.

 

Who was involved?

Data came from children enrolled at birth in seven different studies across the US. Nearly 3,700 children who experienced at least three wheezing events were included, and researchers analyzed the genes of 1,928 of these children. About 32% of these children were AA. Each study site used questionnaires and interviews to collect information from children and their parents over many years.

 

What happened during the study?

The team collected patient characteristics and data on wheezing and asthma and pulled those data together to group each child based on when and how often they wheezed from birth to age 11. Each site also collected DNA samples from the children and sent them to be analyzed for small changes in genes associated with asthma. The researchers used statistics to identify four different wheezing patterns and connect them with specific genetic changes.

 

What happens next?

The team is looking at possible associations between children’s insulin levels, genetic variations, and the development of asthma in childhood.

 

Where can I learn more?

Access the full journal article, titled “Chromosome 17q12-21 Variants Are Associated with Multiple Wheezing Phenotypes in Childhood,” in the American Journal of Respiratory and Critical Care Medicine.

 

Additional Details

This project would not have been possible without ECHO CREW support, as the data came from seven separate birth cohorts brought together by that program. In particular, combining those datasets was essential to getting a large enough sample size to include AA children.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

 

Read the corresponding article.

 

Published: April 1, 2021

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ECHO Study Identifies Genetic Underpinnings of Wheezing Patterns Linked to Asthma

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