Study finds packaging chemical may hinder fertility

Conclusion: A US study has found that perfluorinated chemicals (PFCs), which are used in areas such as food packaging, pesticides, clothing, carpets and personal care products, may be linked to infertility in women.

By Jane Byrne, 29-Jan-2009

The University of CaliforniaLos Angeles (UCLA) study of 1,240 women has found that those with
higher levels of PFCs in their bloodstreams tend to take longer to
become pregnant than those with lower levels.
The findings were published in the journal Human Reproduction today.
PFCs
are found in grease-resistant packaging such as microwave popcorn bags
and pizza boxes; they are also used in manufacturing processes, for
instance for industrial surfactants and emulsifiers.
Findings
According
to the authors, blood samples were taken at the time of the women's
first antenatal visit so that concentrations of the perfluorinated
chemicals PFOS andPFOA could be measured. >
The
researchers said they also interviewed the women at around the 12th
week of pregnancy to find out whether the pregnancy was planned or not
and how long it took them to become pregnant.
Infertility was defined as a time to pregnancy of longer than 12 months or infertility treatment
to establish the current pregnancy, and the results were adjusted for
potential confounding factors such as age, lifestyle and socio-economic
status, continued the report.
The levels of PFOS in the women's plasma ranged from 6.4 nanograms per
millilitre (ng/ml) to 106.7 ng/ml and from less than 1 ng/ml to 41.5
ng/ml for PFOA, the researchers found.
The
team divided the women's levels of PFOS/PFOA into four quartiles, and
found that, compared with women with the lowest levels of exposure, the
likelihood of infertility increased by 70-134 per cent for women in the
higher three quartiles of PFOS exposure and by 60-154 per cent for
those in the higher three quartiles of PFOA exposure.
Hormone interference
The
researchers said that the biological mechanisms by which exposure to
PFOS and PFOA might reduce fertility are unknown, but PFCs may
interfere with hormones that are involved in reproduction.
"Our
data showed that higher proportions of women reported irregular
menstrual periods in the upper three quartiles of PFOA and PFOS
compared with the lowest, and so this could indicate a possible
pathway," said Dr Chunyuan Fei, from UCLA, one of the study's authors.
Professor
Jørn Olsen, Chair of Department of Epidemiology at UCLA, and the
principle investigator of the study, said that the team is waiting for
further studies to replicate its findings in order to discover whether
PFCs should be added to the list of risk factors for infertility.
EFSA opinion
The
European Food Safety Authority's (EFSA) CONTAM Panel adopted an opinion
on PFOS, PFOA and their salts in February last year, after looking at
several different sources of exposure to the two substances.
With
regard to PFOS, the Panel established a Tolerable Daily Intake (TDI) of
150ng/kg per body weight (bw) per day. The Panel noted that the highest
exposed people within the general population might slightly exceed this
TDI, but considered it unlikely that adverse effects of PFOS were
occurring in the general population.
For
PFOA, the Panel established a TDI of 1.5µg/kg bw per day, which it said
was well above the indicative average and high level human exposure (2
and 6 ng/kg bw respectively). While the Panel considered it unlikely
that adverse effects of PFOA were occurring in the general population,
it did note uncertainties in regards to developmental effects.
And the Panel also recommended that further investigations should be carried out in a number of areas related to PFOS and PFOA.