Editorial: Does exposure to landfill waste harm the fetus? BMJ Volume 323, pp 351-2
Researchers in this week's BMJ report small excess risks of birth defects and low birth weight among people living near landfill sites in Great Britain. As 80% of the British population lives within 2km of known landfill sites, these results have important implications and further work is needed to help explain them, say the authors.
Postcodes within a 2km zone of all known landfill sites in Great Britain were identified. Sites not operational between 1982 and 1997 were excluded from the analysis. National registers were used to identify live births, stillbirths and congenital anomalies (including terminations).
The team found a small excess risk of neural tube defects, abdominal wall defects, surgical corrections of certain anomalies, low and very low birthweight. There was no association with stillbirth.
No precise explanation for these findings can be found, say the authors. By including all landfill sites in the country, we avoided the problem of selective reporting, but problems with data quality and confounding factors could have led to spurious associations. Further understanding of the potential toxicity of landfill emissions and possible exposure pathways is needed in order to help interpret the epidemiological findings, they conclude.
The question as to whether these results represent a causal connection between residential landfill exposures and adverse outcomes is unresolved, write two leading experts in an accompanying editorial. Factors, such as crude classification of exposure or residence, and under reporting of anomalies among live and stillborn children by district health authorities, could lead to over or under estimation of the risks of exposure to landfill sites, they conclude.