Ida N. Damgaard

Human breast milk contamination with phthalates and alterations of endogenous reproductive hormones in infants three months of age.

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.

Difference in prevalence of congenital cryptorchidism in infants between two Nordic countries.

BACKGROUND Several investigators have shown striking differences in semen quality and testicular cancer rate between Denmark and Finland. Since maldescent of the testis is a shared risk factor for these conditions we undertook a joint prospective study for the prevalence of congenital cryptorchidism. METHODS 1068 Danish (1997-2001) and 1494 Finnish boys (1997-99) were consecutively recruited prenatally. We also established prevalence data for all newborns at Turku University Central Hospital, Finland (1997-99, n=5798). Testicular position was assessed by a standardised technique. All subtypes of congenital cryptorchidism were included, but retractile testes were considered normal. FINDINGS Prevalence of cryptorchidism at birth was 9.0% (95% CI 7.3-10.8) in Denmark and 2.4% (1.7-3.3) in Finland. At 3 months of age, prevalence rates were 1.9% (1.2-3.0) and 1.0% (0.5-1.7), respectively. Significant geographic differences were still present after adjustment for confounding factors (birthweight, gestational age, being small for gestational age, maternal age, parity, mode of delivery); odds ratio (Denmark vs Finland) was 4.4 (2.9-6.7, p<0.0001) at birth and 2.2 (1.0-4.5, p=0.039) at three months. The rate in Denmark was significantly higher than that reported 40 years ago. INTERPRETATION Our findings of increasing and much higher prevalence of congenital cryptorchidism in Denmark than in Finland contribute evidence to the pattern of high frequency of reproductive problems such as testicular cancer and impaired semen quality in Danish men. Although genetic factors could account for the geographic difference, the increase in reproductive health problems in Denmark is more likely explained by environmental factors, including endocrine disrupters and lifestyle.

Persistent Pesticides in Human Breast Milk and Cryptorchidism

Introduction Prenatal exposure to some pesticides can adversely affect male reproductive health in animals. We investigated a possible human association between maternal exposure to 27 organochlorine compounds used as pesticides and cryptorchidism among male children. Design Within a prospective birth cohort, we performed a case–control study; 62 milk samples from mothers of cryptorchid boys and 68 from mothers of healthy boys were selected. Milk was collected as individual pools between 1 and 3 months postpartum and analyzed for 27 organochlorine pesticides. Results Eight organochlorine pesticides were measurable in all samples (medians; nanograms per gram lipid) for cases/controls: 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (p,p′-DDE): 97.3/83.8; β-hexachlorocyclohexane (β-HCH): 13.6/12.3; hexachlorobenzene (HCB): 10.6/8.8; α -endosulfan: 7.0/6.7; oxychlordane: 4.5/4.1; 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p′-DDT): 4.6/4.0; dieldrin: 4.1/3.1; cis-heptachloroepoxide (cis-HE): 2.5/2.2. Five compounds [octachlorostyrene (OCS); pentachlorobenzene, 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (p,p′-DDD); o,p′-DDT; mirex] were measurable in most samples (detection rates 90.8–99.2%) but in lower concentrations. For methoxychlor, cis-chlordane, pentachloroanisole (PCA), γ -HCH, 1,1-dichloro-2-(2-chlorophenyl)-2,2(4-chlorophenyl)ethane, trans-chlordane, α -HCH, and o,p′-DDE, both concentrations and detection rates were low (26.5–71.5%). Heptachlor, HCH (δ, ɛ ), aldrin, β-endosulfan and trans-heptachloroepoxide were detected at negligible concentrations and low detection rates and were not analyzed further. Seventeen of 21 organochlorine pesticides [p,p′-DDT, p,p′-DDE, p,p′-DDD, o,p′-DDT, HCH (α , β, γ ), HCB, PCA, α -endosulfan, cis-HE, chlordane (cis-, trans-) oxychlordane, methoxychlor, OCS, and dieldrin] were measured in higher median concentrations in case milk than in control milk. Apart from trans-chlordane (p = 0.012), there were no significant differences between cryptorchid and healthy boys for individual chemicals. However, combined statistical analysis of the eight most abundant persistent pesticides showed that pesticide levels in breast milk were significantly higher in boys with cryptorchidism (p = 0.032). Conclusion The association between congenital cryptorchidism and some persistent pesticides in breast milk as a proxy for maternal exposure suggests that testicular descent in the fetus may be adversely affected.

Risk Factors for Congenital Cryptorchidism in a Prospective Birth Cohort Study

Background Risk factors for congenital cryptorchidism were investigated in a prospective birth cohort study in Denmark and Finland from 1997 to 2001. Methodology and Principal Findings In total, 2,496 boys were examined for cryptorchidism at birth (cryptorchid/healthy: 128/2,368) and three months old (33/2,215). Information on risk factors was obtained antenatally (questionnaire/interview) or at birth from birth records. Use of nicotine substitutes during pregnancy (n = 40) and infertility treatment by intrauterine insemination (n = 49) were associated with an increased risk for cryptorchidism, adjusted odds ratio (95% confidence interval) (OR (95%CI)) 3.04 (95%CI 1.00–9.27) and 3.01 (95%CI 1.27–7.15), respectively. No association was seen for mothers (n = 79) who had infertility treatment in form of intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF) treatment (OR 0.71 95%CI 0.21–2.38). In total, 728 (29%) reported to have smoked during pregnancy, however, no increased risk among maternal smokers was found. Furthermore, we found statistically significant associations between cryptorchidism and low birth weight, prematurity, being small for gestational age, substantial vaginal bleeding, and breech presentation, which are in accordance with other studies. Conclusions and Significance Our study revealed two novel risk factors for cryptorchidism: intrauterine insemination and the use of nicotine substitutes in pregnancy. This suggests that cryptorchidism may not only be associated to genetic factors, but also to maternal lifestyle and exposure.

Cryptorchidism and maternal alcohol consumption during pregnancy.

Background Prenatal exposure to alcohol can adversely affect the fetus. We investigated the association between maternal alcohol consumption during pregnancy and cryptorchidism (undescended testis) among newborn boys. Methods We examined 2,496 boys in a prospective Danish–Finnish birth cohort study for cryptorchidism at birth (cryptorchid/healthy: 128/2,368) and at 3 months of age (33/2,215). Quantitative information on alcohol consumption (average weekly consumption of wine, beer, and spirits and number of binge episodes), smoking, and caffeine intake was obtained by questionnaire and/or interview once during the third trimester of pregnancy, before the outcome of the pregnancy was known. For a subgroup (n = 465), information on alcohol consumption was obtained twice during pregnancy by interviews. Results We investigated maternal alcohol consumption both as a continuous variable and categorized. The odds for cryptorchidism increased with increasing weekly alcohol consumption. After adjustment for confounders (country, smoking, caffeine intake, binge episodes, social class, maternal age, parity, maturity, and birth weight) the odds remained significant for women with a weekly consumption of five or more alcoholic drinks (odds ratio = 3.10; 95% confidence interval, 1.05–9.10). Conclusions Regular alcohol intake during pregnancy appears to increase the risk of congenital cryptorchidism in boys. The mechanisms for this association are unknown. Counseling of pregnant women with regard to alcohol consumption should also consider this new finding.

Gender difference in breast tissue size in infancy: correlation with serum estradiol.

Breast tissue in newborn infants is considered to be physiologic and mainly related to exposure to maternal hormones in utero or through breast-feeding. However, controversy exists as to whether breast tissue in later infancy is under the influence of endogenous hormones. Children at 2–4 mo of age have a surge of reproductive hormones, including estradiol, which may affect the mammary gland. In a prospective cohort study of 1126 healthy, 3-mo-old infants, breast tissue size and reproductive hormones were measured. We found that palpable breast tissue (diameter ≥3 mm) is a common physiologic condition present in 78.9% of children, significantly more frequent (p < 0.001) and larger (p < 0.001) in girls than in boys. Girls had significantly higher median estradiol levels than boys (30.0 versus 21.0 pmol/L, p < 0.001). In a multiple regression model including breast tissue size given as quartiles as the dependent variable and weight for gestational age, subscapular skinfold, weight at 3 mo of age and serum estradiol as independent variables, a gender difference was shown. In girls, the estradiol level was positively (p < 0.03) correlated to breast quartile. In boys, no correlations were found. Whether the stimulation of the mammary gland in infancy represents a developmental window that is of biologic significance for breast development and pathology in adulthood remains to be defined.

Infant exposure to persistent organochlorine compounds is higher in Denmark than in Finland.

Significantly poorer male reproductive health has been documented in Danish compared to Finnish men, including a higher prevalence of cryptorchidism and hypospadias. Exposure to environmental pollutants with endocrine disrupting activities has been suggested as a possible contributing factor. In this study, we investigated whether there was a difference in milk and placenta concentrations of persistent organohalogen compounds between the two countries. Organohalogens were analyzed by high-resolution gas chromatography-high resolution mass spectrometry in human milk samples from Finland (n=65) and Denmark (n=65) and placentas (n=168 Danish, 112 Finnish), selected from a population-based cohort. p, p’-DDE was the dominant pollutant. β-HCH, HCB, END-I, dieldrin, OXC, c-HE, and p, p’-DDT were the other main organochlorines detected. Danish samples had significantly higher concentrations of p, p’-DDE, p, p’-DDT, β-HCH, HCB, dieldrin, c-HE, and OXC than Finnish. The organochlorine levels were higher in Danish samples, which suggests higher exposure of Danish infants.