30,000 toenail clippings may hold clues to prostate cancer
World's largest collection of toenail clippings will be analyzed to measure exposure to toxic metals
Researchers are putting more than 30,000 samples of toenail clippings from Atlantic Canadians to good use, trying to determine whether exposure to toxic metals could be behind high rates of prostate cancer in the region.
Cadmium is the metal that we base the study on because there have been previous indications of cadmium being associated with prostate cancer.- Dr. Anil Adisesh , Dalhousie Medicine NB
"Toenails are good for looking at metals," said Dr. Anil Adisesh of Dalhousie Medicine New Brunswick.
Adisesh and Dr. Trevor Dummer of the University of British Columbia will lead the research team.
"Toenails grow fairly slowly … and that means that if we took a clipping we can get probably a month or so's reading of arsenic, and in the case of the study I'm going to look at cadmium as well," Adisesh said
He said there have been previous indications that cadmium is associated with prostate cancer.
Adisesh said the Atlantic provinces have some of the highest rates of prostate cancer in Canada, with the exception of Nova Scotia, where the rate is near the national average at 95 cases per 100,000 men.
In Newfoundland, the rate is 133 cases per 100,000 men, in New Brunswick it is 130 per 100,000 men, and in Prince Edward Island it is 126 per 100,000 men.
Adisesh said there have only been five scientific studies that have measured cadmium exposure and of those, only two used toenails. The other three used urine samples.
Adisesh said the Atlantic toenails include clippings from 149 people who have reported they have had prostate cancer. That is a larger sample size than either of the previous studies that used toenails.
"We would match those cases with men of the same age where we also have toenails for comparison and we should be able to give a robust answer to where the truth lies."
If there is a correlation between exposure to toxic metals and prostate cancer, Adisesh said public health officials can begin focusing more on prevention by lowering exposure.
Obesity may also be a factor
"Arsenic is known to be associated with a number of other cancers and it's suspected also with prostate cancer … when we make the measurements for the cadmium we'll get the results for arsenic and so we can give an answer for that as well."
Adisesh said other factors that could be associated with the high rates of prostate cancer among men in Atlantic Canada include the fact there are more "arsenic-bearing rocks" in the area.
"We also have high rates of obesity in this part of the country and obesity is also associated with prostate cancer and with other cancers,so those are factors as well," he said.
The study is funded by Prostate Cancer Canada and the New Brunswick Health Research Foundation.
The toenail samples were collected through Atlantic PATH, the more common name for the Atlantic Partnership for Tomorrow's Health Study.
Atlantic PATH is part of a national study into how genetics, environment, lifestyle and behaviour contribute to the development of cancer.
"This will tell us whether these toxic metal concentrations are a risk factor for the development of prostate cancer," said Adisesh.
"The results will also inform decisions on suitable levels of environmental exposures to these metals in the future, such as drinking water, food, and soil."