Female exposure to phthalates and time to pregnancy: a first pregnancy planner study.

STUDY QUESTION: Is female exposure to phthalate metabolites associated with reduced fecundity, as estimated by prolonged time to pregnancy (TTP)? SUMMARY ANSWER: Female exposure to monoethyl phthalate (MEP) but not monobutyl phthalate (MBP), monobenzyl phthalate (MBzP) and monoethylhexyl phthalate (MEHP) was associated with a longer TTP. WHAT IS KNOWN ALREADY: Male exposure to phthalates is potentially associated with adverse effects on human fecundity in epidemiological studies, but little is known about the potential effects on female reproduction. STUDY DESIGN SIZE AND DURATION: A cohort study with prospective data based on 229 women from a Danish cohort of 430 first pregnancy planning couples enrolled in 1992-1994. In 2009, urinary analyses of phthalate metabolites were performed on stored urine samples from this cohort. PARTICIPANTS/MATERIALS, SETTING AND METHODS: We analyzed MEP, MBP, MBzP and MEHP in female morning spot urine samples collected daily during the first 10 days of menstrual cycles after discontinuation of contraception. The exposure assessment was based on the mean of two measurements from each woman collected in a period of 6 menstrual cycles. We used Cox regression with discrete time to estimate fecundability ratios (FRs) and 95% CI in relation to the average urine metabolite concentration exposure level, controlled for age and BMI, and the time-varying variables smoking and alcohol. MAIN RESULT AND ROLE OF CHANCE: Urinary concentration of MEP was associated with a decreased fecundity (adjusted FR 0.79; 95% CI: 0.63; 0.99) corresponding to a 21% decreased probability of conception for each natural log (ln) unit increase in MEP. No significant association with TTP was found for MBP, MBzP and MEHP. LIMITATIONS REASONS FOR CAUTION: Subfertile women were overrepresented in the study population due to exclusion of 77 high fertile women who became pregnant in the first cycle when urine collection began. WIDER IMPLICATIONS OF THE FINDINGS: Our results suggest that female exposure to MEP may have an adverse effect on female fecundity, but these findings need to be replicated in a larger and newer cohort study with sufficient exposure contrast if the use of diethyl phthalate (DEP) and thereby MEP in the future potentially should be regulated in cosmetics and industrial consumer products. STUDY FUNDING/COMPETING INTERESTS: The original data collected were founded by Aarhus University Research Foundation, the Danish Medical Research Council and the Danish Medical Health Insurance Foundation. There are no conflicts of interest to be declared. TRIAL REGISTRATION NUMBER: N/A.

Perceived risk prior to mammography as an independent predictor of breast cancer.

OBJECTIVE: The predictive value of perceived risk of breast cancer has previously mainly been compared to statistical risk models. We aimed to compare the women's perceived risk with the observed risk of a breast cancer diagnosis. METHODS: Women referred to mammography at a Danish public hospital (N=1021) were asked to complete a questionnaire about 2 weeks before the examination. The women were asked to rate their perceived risk of having breast cancer on a six-point scale with the anchor points very low risk (1) and very high risk (6). The perceived risk was compared with the diagnosis from the mammography 1-3 weeks later. Multivariate logistic regression was used to adjust for age, category of referral, family history of breast cancer, and previous mammography. RESULTS: The questionnaire was completed by 665 (65%) of the women. Compared to women without breast cancer, a larger percentage of women with breast cancer had estimated their risk as high. The risk difference was 16.5% (95% CI 2.5-30.6), using a cut-off between 4 and 5 on the six-point scale. The odds ratio was 3.6 (95% CI 1.4-8.9) after adjustment for age, category of referral, family history of breast cancer, and previous mammography. The sensitivity, specificity, and predictive value were 0.17, 0.96, and 23%, respectively. CONCLUSION: Women who rated their risk as high had a statistically significant increased risk of having a breast cancer diagnosed at the subsequent mammography. The odds ratio based on the women's risk perceptions remained of the same magnitude after adjustment for category of referral, suggesting that information given by the women contains independent predictive value.

Occupational exposure to pesticides and pregnancy outcomes in gardeners and farmers: a study within the Danish National Birth Cohort.

OBJECTIVE: We conducted a follow-up study to examine whether exposure to pesticides during pregnancy had an adverse effect on pregnancy outcomes among Danish gardeners and farmers. METHODS: Using data from the National Birth Cohort in Denmark, we identified 226 pregnancies of gardeners and 214 pregnancies of farmers during 1997 through 2003. Work activities and exposure to pesticides were reported in an interview (around 16 weeks of gestation). Totally, 62,164 other workers in the cohort served as a reference group. Pregnancy outcomes were obtained by linkage to the national registers. Cox regression was applied to analyze late fetal loss and congenital malformations, and logistic regression was used to analyze preterm birth and small for gestational age. RESULTS: There were no significant differences in the studied pregnancy outcomes between gardeners or farmers and all other workers, except for an increased risk of very preterm birth for gardeners and a favorable birth weight for farmers. With the exception of biologic approach used in gardening, neither work activities nor exposure to pesticides showed a significant increased risk of adverse birth outcomes among gardeners or farmers. CONCLUSIONS: Our data suggest little effect of occupational exposures to pesticides on pregnancy outcomes among gardeners or farmers in Denmark. The results may not apply to other countries.

Time to pregnancy among Danish laboratory technicians who were a part of the National Birth Cohort.

OBJECTIVES: The Danish National Birth Cohort was used to examine whether laboratory work was associated with reduced fecundity. METHODS: Self-reported data on laboratory work and waiting time to pregnancy (0-2, 3-5, 6-12 and > 12 months) were used for 829 female laboratory technicians interviewed in 1997-2003. Altogether 6250 female teachers formed the reference group. A discrete-time survival analysis with a complementary log-log link was applied to estimate the fecundability ratio between the exposed and unexposed women, with adjustment for maternal age, gravidity, smoking, prepregnancy body mass index, and paternal job. RESULTS: No difference in time to pregnancy was found between the laboratory technicians and teachers or between the laboratory technicians with different exposures. The adjusted fecundability ratio for the laboratory technicians was 0.94 [95% confidence interval (95% CI) 0.86-1.02] for all pregnancies and 0.98 (95% CI 0.86-1.13) for first pregnancies. A healthy worker effect was found for the laboratory technicians working with the work processes under study. CONCLUSIONS: The results do not suggest that laboratory work in Denmark at present impairs female fecundity.