DDT Facts and Figures

Lies, damn lies, and environmental statistics.

Feeding primates more than 33,000 times the average daily human exposure to DDT (as estimated in 1969 and 1972) was “inconclusive with respect to a carcinogenic effect of DDT in nonhuman primates.”

[J Cancer Res Clin Oncol 1999;125(3-4):219-25]

Yeah, but what about real world human cancer patients?  Well, I’m glad you asked.

-A nested case-control study was conducted to examine the association between serum concentrations of DDE and PCBs and the development of breast cancer up to 20 years later. Cases (n = 346) and controls (n = 346) were selected from cohorts of women who donated blood in 1974, 1989, or both, and were matched on age, race, menopausal status, and month and year of blood donation. “Even after 20 years of follow-up, exposure to relatively high concentrations of DDE or PCBs showed no evidence of contributing to an increased risk of breast cancer.

[Cancer Epidemiol Biomarkers Prev 1999 Jun;8(6):525-32]

-”To prospectively evaluate relationships of organochlorine pesticides and PCBs with breast cancer, a case-control study nested in a cohort using the Columbia, Missouri Breast Cancer Serum Bank. Women donated blood in 1977- 87, and during up to 9.5 years follow-up, 105 donors who met the inclusion criteria for the current study were diagnosed with breast cancer. For each case, two controls matched on age and date of blood collection were selected. Five DDT analogs, 13 other organochlorine pesticides, and 27 PCBs were measured in serum. Results of this study do not support a role for organochlorine pesticides and PCBs in breast cancer etiology.

[Cancer Causes Control 1999 Feb;10(1):1-11]
-”We measured plasma levels of DDE and PCBs prospectively among 240 women who gave a blood sample in 1989 or 1990 and who were subsequently given a diagnosis of breast cancer before June 1, 1992. We compared these levels with those measured in matched control women in whom breast cancer did not develop. Data on DDE were available for 236 pairs, and data on PCBs were available for 230 pairs. Our data do not support the hypothesis that exposure to [DDT] and PCBs increases the risk of breast cancer.”

[N Engl J Med 1997;337:1253-8]

As you will see if you check out the JunkScience site - DDT has been blamed for a lot of things - only to have the science not support the preferred (predetermined) conclusion of environmentalists.

Don’t want to trust a site called JunkScience for information?  Well, perhaps go here and do your own search on DDT and breast cancer.  As with any epidemiological study looking for tenuous associations, you will find data for and against causality.  However, I found far more articles that found no association than those that did.  As always, be careful of any abstract that uses the word “trend” to describe its findings.  The word “trend” in a scientific paper means that the data didn’t show what we wanted it to, so we’re trying to make it sound significant, even though it’s not.  One of my graduate students or residents would receive an immediate EPIC FAIL if they tried to give me a manuscript of their research using the “T” word.