New analysis of data gathered by the University of Auckland’s Growing Up in New Zealand study has shown that children living in neighbourhoods where there are more wood or coal fire-heated houses may be at greater risk of skin diseases as well as respiratory diseases.

Researcher Dr Hakkan Lai examined data from nearly 3,500 of the more than 6,500 study children and led the analysis with guidance from Professor Cameron Grant, Head of the Department of Paediatrics at the University of Auckland’s Faculty of Medical and Health Sciences.

The investigators found that children were more likely to be prescribed respiratory and skin medications if they lived in areas with a larger number of wood or coal fire-heated homes.

And the study found that it was smoke emitted from neighbouring chimneys, rather than from the chimney in the child’s own home, that posed the greatest risk – contributing more to the pollution of air in a child’s home.

“While it’s been known that respiratory diseases may be triggered by wood smoke, the concept that neighbourhoods with high emissions of wood or coal smoke might trigger skin diseases is relatively new to science,” says Dr Lai.  “There have been limited studies about this internationally – around four – and their focus was on indoor wood or coal heating in the child’s own home, rather than their neighbourhood.

“But what we know is that the concentration of smoke tends to be very low below the chimney the smoke has come from, increasing the further you move away from that chimney. If you multiply the height of the chimney by ten and then move that distance horizontally, that’s where the smoke will actually be most concentrated.”

The research found that in their first four years of life, 40% of the children received respiratory medication prescriptions, 71% received skin medication prescriptions and 79% received respiratory and/or skin medication prescriptions during the cooler season. Most of the skin medication prescriptions were for the treatment of atopic dermatitis, or eczema.

The findings suggest that high densities of residential fires could be creating significant health problems for children, particularly as housing density increases.

“It’s crucial for the health of our most vulnerable New Zealanders that we use wood burners responsibly and continue adopting cleaner forms of home heating in New Zealand, such as heat pumps and pellet burners.”

ENDS

Additional information

How was the research carried out?

• The researchers looked at the longitudinal data gathered by the Growing Up in New Zealand study about the cohort children at different ages (in pregnancy, nine months, two years and four and a half years)They reviewed this alongside information from other databases, such as what respiratory and skin medications the children had been prescribed.
• The children’s residential locations were geocoded and linked to information from the 2013 census, including the density of wood or coal heated households.

Combining the different sources of information in this way enabled the researchers to discover the connection between domestic fires and the incidence of skin disease in children.

“The ability to take different datasets and analyse issues like this is a feature of the new research landscape,” says Professor Grant. “We’re able to build a bigger, richer picture to help us answer questions to improve the health and wellbeing of New Zealanders.”

How many prescriptions did the children receive in their first four years of life?

The average number of prescriptions dispensed in the children’s first four years of life were:

• For respiratory medications: 6.6
• For skin medications: 10.5
• For respiratory or skin medications: 14.

What are the risks of using wood or coal burners for home heating?

Burning wood, coal, gas, diesel or other materials for home heating releases air pollutants into air.  These include carbon monoxide, sulphur dioxide, benzene and nitrogen dioxide. We each breathe about 14,000 litres of air each day so contaminants in outdoor air can adversely affect health; particulate matter can contribute to heart and lung diseases, leading to hospital admissions and premature death. Outdoor air pollution can also cause cancer.

Land Air Water Aotearoa (lawa.org.nz)
​​​​​​​Environmental Health Indicators New Zealand (ehinz.ac.nz)

How many households use wood or coal fires for heating?

Based on 2013 Census data, about a third of New Zealand homes (37%) use wood and coal fires for home heating. This compares to 41% in 2006. Households in the South Island are more likely to use wood or coal fires than those in the North Island. Coal fires tend to be used more in the West Coast and the Waikato.

Environmental Health Indicators New Zealand (ehinz.ac.nz)

Why are children more vulnerable to environmental pollutants than adults?

The reasons why children are more susceptible to the negative health effects of certain environmental exposures include:

• They eat more food, drink more fluids, breathe more air per kilogram of body weight, and have a larger skin surface in proportion to their body size than adults. This means their exposure to (potentially) harm-causing agents or substances is greater for their size than in adults.
• Children absorb more of some substances (such as lead) from their gut.
• Their organs and body systems are still developing.
• Children's behaviour, such as putting hands and objects in their mouth, as well as their play and exploratory activities, influence their exposure.

Environmental Health Indicators New Zealand (ehinz.ac.nz)

About Growing Up in New Zealand

Growing Up in New Zealand is New Zealand’s contemporary and largest longitudinal study of child development. The University of Auckland study is following a cohort of more than 6,800 children born in 2009 and 2010, starting in pregnancy and continuing until the children are at least 21 years old.

The ethnicity and socio-demographic characteristics of the cohort children are broadly generalisable to those of children being born in New Zealand today and, since 2008, Growing Up has been capturing their unique life stories via a series of data collection waves.

At each data collection wave information is collected across six key areas:

• Health and wellbeing
• Psychosocial and cognitive development
• Education
• Family/whānau
• Culture and identify
• Societal context and neighbourhood environment.
• To date, more than 90,000 interviews have been carried out and more than 50 million pieces of data collected. This information, and its analysis, is able to inform policies and programmes that better meet the needs of children and families in New Zealand.

Information from Growing Up in New Zealand has provided insights into a diverse range of areas such as paid parental leave, immunisation, poverty and material hardship, family housing and mobility, household safety, bullying, participation in Early Childhood Education, and pre- and post-natal depression among fathers.

Download the article

Lai, H., Camargo, Jr Carlos A., Woodward, A., Hobbs, M., Pillai, A., Morton, S., Grant, C. (October 2018). Long-term exposure to neighbourhood smoke from household heating and risk of respiratory and dermatological prescription medications – Growing Up in New Zealand child cohort study. European Journal of Allergy and Clinical Immunology (Allergy). https://onlinelibrary.wiley.com/doi/abs/10.1111/all.13615