A lot of people working in environmental health, not least ourselves, were excited last year by an apparent move on the part of the International Agency for Research on Cancer (IARC) to start treating chemical contaminants in the environment as an important factor behind the disease.
Now we are waiting to see if this attitude shift translates into policy. Obviously this will take time, but the interview below with IARC head Professor Christopher Wild suggests they have some way to go, as he gives little evidence that IARC is giving consideration to chemical contaminants except in air pollution.
Q. What are the links between cancer and environment?
Professor Wild of the IARC quite rightly states that the majority of cancers have an environmental basis: we know this from the seminal study by Lichtenstein (2000) and a follow up study by his colleague, Czene (2002).
But Professor Wild then goes on to define the environment as a geneticist would, to include the likes of lifestyle, diet and occupation as well as the chemical contaminants which are the cause of much concern.
Using the ‘broad’ definition of the environment gives him the opportunity to talk about what we want on the public health agenda, i.e. cancer prevention.
However, the “prevention” he speaks of is in terms of lifestyle changes, diet, tobacco cessation and physical exercise. These measures are obviously very important and necessary, but shouldn’t be used to dodge talking about prevention of cancer by limiting involuntary exposures to carcinogens.
Professor Wild does in fact touch on environmental exposure to chemicals but seems to concentrate on air pollution and solid fuel exposure in homes, but doesn’t mention pesticides, EDCs or of involuntary exposure to these chemicals in consumer products and diet.
His language changes when comparing natural to anthropogenic exposures. He talks of “strong evidence” that aflatoxins and arsenic contaminated water is a factor in cancer. But then he only talks of “some” studies linking air pollution to human cancers.
Throughout his answer involuntary exposures to chemicals from human activities in the last 60 years was not addressed.
All the prevention measures he talks of in reply to the first question are based around exposures that are not involuntary (lifestyle) or are based on a problem where measures have been slowly put into practice i.e. air pollution, especially in Western countries.
Q. How IARC is researching these links especially with relation to cancer, environment, chemicals, life style etc.?
When asked about IARC’s research into environmental exposures and links to cancer, ‘specifically’ non-lifestyle exposures Professor Wild speaks about the IARC monographs program.
On the face of it the review of previously classified human/animal carcinogens is good to hear. However, when talking about research IARC carries out into cancer aetiology and factors which may be involved by bringing together laboratory studies and human epidemiology, again, he uses air pollution as an example.
Citing a large scale European study looking at the biological effects of ‘higher levels’ of air pollution. Here, Professor Wild did not take advantage of the opportunity to talk about chemical exposures or the effect that low levels of chemicals may have on health.
On a positive note, Professor Wild was interested in concerns that current toxicological tools are insufficient to measure real-world exposures, saying that more research is needed to monitor and measure exposures to “cocktail effects” in complex mixtures.
Anyone who read this week’s excellent Newsweek article on explanations for increasing rates of obesity in babies might be wondering what the biological processes are behind this trend. (Anyone who read our own piece on this last week will appreciate the extra detail.)
This video lecture explains how chemicals can cause the body to develop more fat cells. It focuses on tributyl tin (TBT), a fungicide and anti-fouling treatment, which may already be in humans at levels sufficient to interfere with the way fat cells are laid down.
UPDATE: Unfortunately the video is no longer available.
We are looking at ways we might be able to resolve the issue.
Also worrying is the suggestion that TBT is actually a more powerful synthetic hormone than the natural ones which regulate fat deposition in the body.
Tags: Cancer, EndocrineDisruption
Breast Cancer UK have produced a useful overview of how endocrine disruptors (EDCs) are connected to cancer, how to avoid the EDC of the moment, BPA, and some tips for encouraging action on BPA in the UK.