A chemical found in non- stick cookware and food packaging has been linked to thyroid disease.
The substance, PFOA, which is found throughout the home, has previously been branded potentially carcinogenic.
Now it has been further called into question by research which shows that those with higher levels in the blood have higher rates of thyroid disease.
Women – who are more susceptible to thyroid problems – are at double the risk, according to the study. PFOA is used in industrial and consumer goods including non- stick cookware such as Teflon-coated pans – where it becomes unstable at very high temperatures – fast-food packaging, and flame-resistant and stain-resistant coatings for carpets and fabrics.
It appears to get into the body by being swallowed or breathed in and there is no way of lowering levels in the blood.
Researcher David Melzer, a professor of epidemiology and public health, said: ‘There have long been suspicions that PFOA concentrations might be linked to changes in thyroid hormone levels.
‘Our analysis shows that in the “ordinary” adult population there is a solid statistical link between higher concentrations of PFOA in blood and thyroid disease.’
However, other experts pointed to research into workers with consistently high levels of exposure to the chemical that has not found a link with thyroid disease.
Concerns over PFOA (perfluorooctanoic acid) and a similar chemical PFOS since the 1990s led U.S. safety chiefs to link them to cancer. Manufacturers have agreed to phase them out by 2015.
NOTE: In the U.S. – these types of pans are still available. ~ J.B.
The British researchers, from the University of Exeter and the Peninsula Medical School, analysed blood samples from the U.S. Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey.
Samples from almost 4,000 adults taken between 1999 and 2006 were analysed for chemicals including PFOA and PFOS, the journal Environmental Health Perspectives reports.
The researchers found those with the highest 25 per cent of PFOA concentrations were more than twice as likely to have thyroid disease than individuals with the lowest 50 per cent of PFOA concentrations.
The study also showed that 16 per cent of women in the top quarter had the disease compared with just 8 in the bottom quarter.
The type of thyroid problem, whether over-active or underactive, was unknown.
Previous animal studies have shown the compounds can affect the function of the thyroid hormone system.
This is essential for maintaining heart rate, regulating body temperature and supporting many other body functions, including metabolism, reproduction, digestion and mental health.
Tamara Galloway, a professor in Ecotoxicology at the University of Exeter and the study’s senior author, said: ‘Our results highlight a real need for further research into the human health effects of lowlevel exposures to environmental chemicals like PFOA that are ubiquitous in the environment and in people’s homes.’
But Dr Diane Benford, Head of Toxicology of Food at the Food Standards Agency, said: ‘Studies of workers with higher exposure to these compounds have not shown consistent evidence of increased risk of thyroid disease, which would be expected if effects are occurring in the general population.’
Posted by Jenny Hope for The Daily Mail, January 21, 2010.
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