Chemical industry study disputes hormone disrupter effects

This conflicts with the results of earlier studies conducted at the University of Missouri (UM), which reported increases in prostate weights and decreased efficiency of sperm production in male mice whose mothers were exposed to very low doses of bisphenol A (2 and 20 micrograms per kilogram of body weight/day).

Based in part on this research, it has been hypothesized that low level exposure to certain compounds may have adverse effects on hormone responsive tissues

The SPI/CEFIC study found none of these effects at the same dose levels, and no effects at levels 10-fold higher and 10-fold lower. According to CEFIC, its study was significantly larger and more comprehensive than the previous work, conducted by researchers at the UM.

SPI says that the results call into question the relevance of the UM findings, “but they also cast further doubt on the broader ‘low-dose theory’ advanced by some investigators of the endocrine issue.”

The “low dose hypothesis” suggests that exposure to very small amounts of a substance well below the exposure levels known to have effects on exposed test animals, and also below the no observed effect level for these same effects, may produce different or opposite biological effects.