Tuesdays with Turtles – Leatherbacks in Gabon

The LA Times features a study arising from the Silent Spring institute.

Common chemicals are linked to breast cancer – Los Angeles Times

More than 200 chemicals — many found in urban air and everyday consumer products — cause breast cancer in animal tests, according to a compilation of scientific reports published today.

Writing in a publication of the American Cancer Society, researchers concluded that reducing exposure to the compounds could prevent many women from developing the disease.

The research team from five institutions analyzed a growing body of evidence linking environmental contaminants to breast cancer, the leading killer of U.S. women in their late 30s to early 50s.

Experts say that family history and genes are responsible for a small percentage of breast cancer cases but that environmental or lifestyle factors such as diet are probably involved in the vast majority.

“Overall, exposure to mammary gland carcinogens is widespread,” the researchers wrote in a special supplement to the journal Cancer. “These compounds are widely detected in human tissues and in environments, such as homes, where women spend time.”

The scientists said data were too incomplete to estimate how many breast cancer cases might be linked to chemical exposures.

The resources to come out of this study include two databases, one that summarizes animal mechanistic studies, and one that summarizes human epidemiological studies. It’s a good start and I hope these databases are continually expanded. The study was essentially a big lit review and data organization project.

There are two major issues with the way carcinogenicity is studied. Firstly, animals other than humans are dosed at high levels to test for possible cancer outcomes. This leaves most researchers vulnerable to the charge that these high dose studies do not translate well to humans because the dose-response relationship at ambient levels is not well studied. So, the obvious criticism is that just because cancer endpoints were seen at high levels does not mean that the same thing will happen at low levels. This cuts both ways, though. We’re seeing with bisphenol A that low doses can cause more harm than intermediate doses. Another issue is the additivity of the interactions. Does 1 “dose” of PAH + 1 “dose” of PCB = 2 “doses” of PAH? We’re exposed to a whole host of chemicals all our lives, who knows which ones add, which ones subtract, which ones multiply, etc.

Of course, as with most diseases, some macro variables dominate. For instance, the US has seen 8-9% decline in breast cancer incidence recently due to a decreased use of hormone replacement therapy. So, as with all diseases, taking care of some of these big ticket items is very important. One discouraging story I read today reported on a four percentage point decline in mammograms (70 to 66%) in women age 40 and older. Why? decreased access to health insurance and dropping the ball on promotion.

The depressing fact of the matter is that the boring basics of good preventative healthcare, screening, good lifestyle and diet are the most important factors, and if we take care of these factors, we will make most health issues easier to deal with.

The Canadian Medical Association Journal is denouncing the federal government for what it expects will be Canada's continued efforts to block international controls on asbestos at UN-sponsored negotiations next week.

A strongly worded editorial, appearing in tomorrow's issue of the journal, says the government "knows what it is doing is shameful and wrong" and compared Ottawa's moral stature in continuing to promote the use of the cancer-causing material to that of arms traders.

The negotiations, known as the Rotterdam Convention, are to start Oct. 27 in Rome. The focus of the talks will be on whether to add the chrysotile variety of asbestos to the world's list of most dangerous substances. Once a substance is listed, countries must give prior informed consent that they know they are buying a highly dangerous material before being allowed to accept any imports.

via globeandmail.com: Medical journal blasts Ottawa for promoting asbestos abroad

Canada’s national shame, its export of a killer product not used by Canadians to developing countries where the safeguards it insists on for the ‘safe” use of this product can’t possibly be carried out or enforced. For god’s sake, it’s 700 jobs, and people who can be retrained to do something that does not kill people.