Californian Medical Association backs moves to limit BPA exposure, and other BPA developments in October.

November 6, 2010 at 7:24 pm | Posted in Briefing | 3 Comments

Sperm and EggOctober was a busy month for BPA. The Californian Medical Association passed a resolution “recogniz[ing] a public health concern for Bisphenol A (BPA), a known endocrine disruptor, and endors[ing] efforts to reduce towards elimination of BPA in consumer products”. (CMA Resolution 116a-10, PDF)

The government of Canada formally declared bisphenol A, to be a toxic substance, while the Danish Minister of Food said Denmark will not be rescinding its precautionary ban on BPA. The European Food Safety Authority’s recent statement that it has no reason to change the tolerable daily intake level for BPA is becoming increasingly controversial.

The progress of the debate is well summarised by John Hendel of The Atlantic. Hendel charts the emergence of the controversy over the use of the substance, with researcher Fred vom Saal as a central character in the story, and includes an explanation of why toxicology needs to be reformed.

Bryan Walsh, a TIME magazine journalist who has covered BPA in detail adds his two cents to recent developments, offering his opinion on the direction in which things are going. In general, knowledge about and awareness of BPA seems much higher in the US than in Europe.

While Walsh speculates about regulation, USA Today and The Independent (UK) both covered a story about how investment advisory firms are rating companies on issues such as how quickly they are eliminating problem chemicals such as BPA from their products.

Moves toward more BPA-free products than just baby bottles were given added impetus by research showing that pregnant women who eat canned vegetables are unwittingly exposing their infants during fetal development. A second paper suggests that BPA levels in humans are too high to be accounted for by dietary exposure alone (Taylor et al. 2010).

Further research into the effects of BPA on fertility was published, with a new study funded by US healthcare provider Kaiser Permanente (picked up by USA Today) finding that Chinese workers who are highly exposed to BPA have reduced semen quality (Li et al. 2010).

In the spirit of constructive criticism the conservative website Junk Science slammed the research, saying that rather than being published in the journal of Fertility and Sterility, the study “may as well have been published in the journal of Futility and Stupidity”.

The Kaiser Permanente study hardly came out of nowhere: there is a small body of research which suggests that BPA harms fertility, with low levels of BPA having been found to reduce semen quality in rats (Herath et al. 2004) and fish (Lahnsteiner et al. 2005).

Evidence of harm to fertility from BPA in human studies is mixed. Mendiola et al. 2010 recently found that although urinary BPA concentrations have been associated with altered levels of sex hormones, researchers could only find evidence of small resulting changes to reproductive function which are of “uncertain clinical significance”.

In contrast, Meeker et al. 2010 did find an association between BPA concentration and lower semen quality in men, a finding which has been corroborated by the new study. A new review in Reproductive Toxicology summarises the currently available data (Salian et al. 2010).

Meanwhile, an updated review has been published which discusses BPA’s role as both an endocrine active compound, its ability to make epigenetic changes through DNA methylation, and its reported effects of BPA on brain and behaviour (Wolstenholme et al. 2010).

New research has found that rats exposed neonatally to BPA were more likely as adults to develop pre-cancerous lesions on the prostate gland (Prins et al 2010). The research was heavily criticised by a cancer charity; we point out some of the more positive aspects of the paper here.

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