November 21, 2008

reaction to study suggesting link between hairspray and genital birth defect, as published in the journal Environmental Health Perspectives

The study found a link between chemicals found in hairspray and genital birth defects in boys, through a retrospective study of women based on a number of factors including occupation.

Prof Richard Sharpe, MRC Human Reproductive Sciences Unit, University of Edinburgh, said:

“This study shows an association between hypospadias in sons and hairpsray use in the mother and suggests this may indicate effects of phthalates in the hairspray. This is possible but is a big leap of faith. In some (but not all) animal models, some (but not all) phthalates can suppress fetal testosterone production, which plays an important role in penis development; lack of adequate testosterone can result in hypospadias. However, the evidence that phthalates can suppress testosterone production by the fetal testis in humans is completely equivocal with two studies providing (indirect) support and three studies suggesting no such effect. Time (more and better designed studies) will tell which is correct. In the meantime, it is perhaps wiser to concentrate on the more important observation in this study which suggests that increased folate intake in pregnancy may protect against hypospadias in the offspring. This is something that pregnant women can do something positive about and which we know can have other benefits, namely protection against spina bifida. With regard to hairsprays, my advice has long been that women who are planning a pregnancy should avoid (or at least minimise) use of cosmetics, body creams/lotions etc, especially in the first 3 months of pregnancy – this advice is given not because we know that the ingredients can do harm to the baby (as we do not know this), but because it can only do good for the baby (i.e. avoiding unnecessary chemical exposures) and is again something positive that the mother can do for her baby.”

Vivienne Parry, Science Writer and Broadcaster, and author of The Truth About Hormones, said:

“I have many concerns about the conclusions that could be drawn from this study. A case-control study involving retrospective telephone interview is not sufficient to accurately investigate levels of exposure to hairspray or any other chemicals. If this were a study only of hairdressers, whose occupation exposes them to hairspray on a regular basis, then I would be a lot more convinced than I am by a study that has asked people of different occupations and lifestyles to recall their exposure levels. The authors studied hairdressers as a group within their sample population and in their results state that hairdressers were not at a significantly increased risk.”