Children living near coal seam gas extraction sites are more likely to hospitalised for blood and immune diseases, an Australian study has found.
Queensland University researchers compared age-specific hospitalisation rates for almost 81,000 children living in three locations: one where coal seam gas is extracted, a coal mining area (CHI) and a rural area where no mining occurred (RLI) between 1995-2011.
All locations are in Queensland, where the CSG industry has been expanding since 2005.
In what was the largest effect size identified in the study, a 467% per year increase in ‘blood/immune’ disease admission rates for children aged five to nine was seen in the CSG area per year relative to the rural area with no mining.
The most common diagnosed conditions were agranulocystosis, secondary thrombocytopenia and unspecified anaemia.
The total number of blood/immune disease admissions were 67, 46 and 10 for the CSG, coal and rural areas respectively.
The authors noted that the large effect size in the CSG area must be considered alongside the average annual rates for these age groups “which ranged from 0.79 to 1.19 per 100,000 persons for the three study areas indicating a low base rate where small numbers would likely contribute to larger estimates and wider confidence intervals”.
In other findings, adjustment for covariates revealed a 95% increase per year in neoplasms admission rates in the CSG area relative to the rural area.
The average annual rate for neoplasm in the 10-14 age group was 3.2 per 100,000 in the CSG area, compared to 2.9 in the coal and 1.1 in the rural area.
Meanwhile the strongest associations were observed for ‘all cause’ admission rates for 5-9 year olds and respiratory disease for 0-4 and 10-14 year olds.
Other notable comparisons between CSG and rural area included a 12% annual increase in congenital malformation in the 0-4 group and a 19% higher digestive disease in the 10-14 year olds.
The study authors commented that there was public unease about expansion of unconventional natural gas development (UNGD), with a growing body of research pointing to a range of potential health impacts that may be caused by air contamination and ground and surface water contamination.
Writing in Maternal and Child Health Journal, Dr Angela Werner (PhD) from the University of Queensland’s Sustainable Minerals Institute said previous Australian studies had shown higher hospitalisation rates for adults in CSG areas for neoplasms and blood/immune disease and congenital abnormalities . This was the first study in Australia to show similar increases for hospitalisations among children in CSG areas.
While noting limitations of the study, such as the inclusion of repeat admissions and low case numbers and outcomes in some age groups, the results indicated “possible age-specific trends for potential health impacts of CSG within a child and adolescent cohort in Queensland,” they said.
However they emphasised that the research was not intended to examine potential causal associations, and said more sophisticated studies were warranted to explore this.
“These findings show that there are potential maternal and child health policy implications to consider in relation to CSG development activity. Additional work is needed to confirm the associations presented here and in other studies but the current conclusions suggest the need for the consideration of the impacts of UNG activities in relation to the location of communities in which the activities occur”.
“Governments should establish monitoring systems to allow for tracking the incidence and prevalence of disease thought to be associated with UNGD in conjunction with exposure data, particularly for those exposures that occur in utero”.