Human breast milk phthlates affect infant hormones

[Guest guest]

Human Breast Milk Contamination with Phthalates and Alterations of

Endogenous Reproductive Hormones in Infants Three Months of Age

Katharina M. Main et al.

http://ehp.niehs.nih.gov/members/2005/8075/8075.html

http://ehp.niehs.nih.gov/members/2005/8075/8075.pdf

Abstract

Phthalates adversely affect the male reproductive system in animals. We

investigated whether phthalate monoester contamination of human breast

milk had any influence on the postnatal surge of reproductive hormones in

newborn boys as a sign of testicular dysgenesis.

Design: We obtained biologic samples from a prospective Danish-Finnish

cohort study on cryptorchidism from 1997 to 2001. We analyzed individual

breast milk samples collected as additive aliquots 1-3 months postnatally

(n = 130; 62 cryptorchid/68 healthy boys) for phthalate monoesters

[mono-methyl phthalate (mMP), mono-ethyl phthalate (mEP), mono-n-butyl

phthalate (mBP), mono-benzyl phthalate (mBzP), mono-2-ethylhexyl phthalate

(mEHP), mono-isononyl phthalate (miNP)]. We analyzed serum samples

(obtained in 74% of all boys) for gonadotropins, sex-hormone binding

globulin (SHBG), testosterone, and inhibin B.

Results: All phthalate monoesters were found in breast milk with large

variations [medians (minimum-maximum)]: mMP 0.10 (< 0.01-5.53 µg/L), mEP

0.95 (0.07-41.4 µg/L), mBP 9.6 (0.6-10,900 µg/L), mBzP 1.2 (0.2-26 µg/L),

mEHP 11 (1.5-1,410 µg/L), miNP 95 (27-469 µg/L). Finnish breast milk had

higher concentrations of mBP, mBzP, mEHP, and Danish breast milk had

higher values for miNP (p = 0.0001-0.056). No association was found

between phthalate monoester levels and cryptorchidism. However, mEP and

mBP showed positive correlations with SHBG (r = 0.323, p = 0.002 and r =

0.272, p = 0.01, respectively); mMP, mEP, and mBP with LH:free

testosterone ratio (r = 0.21-0.323, p = 0.002-0.044) and miNP with

luteinizing hormone (r = 0.243, p = 0.019). mBP was negatively correlated

with free testosterone (r = -0.22, p = 0.033). Other phthalate monoesters

showed similar but nonsignificant tendencies.

Conclusions: Our data on reproductive hormone profiles and phthalate

exposures in newborn boys are in accordance with rodent data and suggest

that human Leydig cell development and function may also be vulnerable to

perinatal exposure to some phthalates. Our findings are also in line with

other recent human data showing incomplete virilization in infant boys

exposed to phthalates prenatally.

Environ Health Perspect 114: 270-276 (2006).

doi:10.1289/ehp.8075 available via http://dx.doi.org/

[Online 7 September 2005]