are you all aware that it is the same strain used in other studies used to promote safety of gmo. the main difference in this study (which followed the same protocols as the gmo promoted studies as far as i can tell - read the actual paper for the details) is that the study was carried out for the full life term of the rats, not just 13 weeks as in the case for the existing safety studies such as hammond et al 2004.
the other main protest seems to be the sample size of the groups, again this is not dissimilar to the existing safety studies, so for those that want to dismiss this study based on sample size, you HAVE to dismiss the existing studies as well.
These rats have a very high rate of developing tumors. The longer they are alive the greater the chance is of them developing, too. To use 10 as opposed to 10 or 12 groups of 10 for a control group is ridiculous. It's statistically insignificant. Their "results" mean nothing.
Edit: Personally, I could care less about GMO's. I don't really have a stance on the matter. This is just very bad science.
Here is some information abour tumor development in this type of rat:
Most of the tumor susceptibility research in unspayed rats has been done on different strains of laboratory rats. Strains and populations differ in how susceptible the females are to developing tumors. Susceptibility may vary widely.
Below are some studies that examine the percentages of female rats of a particular strain that develop mammary tumors. Where reported, the percentage of benign vs. cancerous mammary tumors is included below:
- 47% of female Sprague-Dawley rats developed mammary tumors. 12% of these tumors were malignant (Solleveld et al. 1986).
- 49% of female Sprague-Dawley rats developed mammary tumors (24 our of 49), 8.2% developed mammary carcinomas (4 out of 49) (Hotchkiss 1995)
- 71% of female Sprague-Dawley rats developed mammary tumors, of which 18% were carcinomas (Durbin et al. 1966)
- 76% of female Sprague-Dawley rats, most of which were benign fibroadenomas (Kaspareitt and Rittinghausen 1999)
- 39% of female Sprague-Dawley rats develop pituitary tumors (Kaspareitt and Rittinghausen 1999)
So after the rats go through menopause (450-540 days), the rates of tumors increase and the increase AGAIN after the end of the second year (600-800 days). Hmm... right before their study ends.....
They did not accumulate enough data to rule out the randomness of tumors in these rats.
Edited by Imaginarynumber1, 21 September 2012 - 10:08 AM.