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Background: Pregnancy and parity are associated with subsequent breast cancer risk. Experimental and epidemiologic data suggest a role for pregnancy sex steroid hormones.

Methods: We conducted a nested case–control study in the Northern Sweden Maternity Cohort (1975–2007). Eligible women had provided a blood sample in the first 20 weeks of gestation during a primiparous pregnancy leading to a term delivery. The current study includes 223 cases and 417 matched controls (matching factors: age at and date of blood collection). Estrogen receptor (ER) and progesterone receptor (PR) status was available for all cases; androgen receptor (AR) data were available for 41% of cases (n = 92). Sex steroids were quantified by high-performance liquid chromatography tandem mass spectrometry. Odds ratios (ORs) and 95% confidence intervals were estimated using conditional logistic regression.

Results: Higher concentrations of circulating progesterone in early pregnancy were inversely associated with ER+/PR+ breast cancer risk (ORlog2: 0.64 (0.41–1.00)). Higher testosterone was positively associated with ER+/PR+ disease risk (ORlog2: 1.57 (1.13–2.18)). Early pregnancy estrogens were not associated with risk, except for relatively high estradiol in the context of low progesterone (split at median, relative to low concentrations of both; OR: 1.87 (1.11–3.16)). None of the investigated hormones were associated with ER–/PR– disease, or with AR+ or AR+/ER+/PR+ disease.

Conclusions: Consistent with experimental models, high progesterone in early pregnancy was associated with lower risk of ER+/PR+ breast cancer in the mother. High circulating testosterone in early pregnancy, which likely reflects nonpregnant premenopausal exposure, was associated with higher risk of ER+/PR+ disease.

Pregnancy, parity, and circulating steroid hormone levels are associated with risk of breast cancer, but little is known about hormone concentrations during pregnancy and subsequent breast cancer risk. We evaluated early pregnancy (<140 days gestation) serum estradiol, estrone, progesterone, and testosterone and breast cancer risk in a nested case-control study in the Finnish Maternity Cohort. The cohort includes 98% of pregnancies registered in Finland since 1983. Individuals with samples collected in the first pregnancy leading to a live birth were eligible. Breast cancer cases (n = 1,199) were identified through linkage with the Finnish Cancer Registry; 2,281 matched controls were selected using incidence density sampling. ORs were calculated using conditional logistic regression. Hormone concentrations were not associated with breast cancer overall. Estradiol was positively associated with risk of breast cancer diagnosed age <40 [4th vs. 1st quartile OR 1.60 (1.07-2.39); Ptrend = 0.01], and inversely associated with breast cancer diagnosed at age ≥40 [4th vs. 1st quartile OR 0.71 (0.51-1.00); Ptrend = 0.02]. Elevated concentrations of the steroid hormones were associated with increased risk of estrogen receptor (ER)- and progesterone receptor (PR)-negative tumors in women age <40 at diagnosis. We observed no association between steroid hormones and ER(+)/PR(+) disease. These data suggest a positive association between high concentrations of early pregnancy steroid hormones and risk of ER(-)/PR(-) breast cancer in women diagnosed age <40, and an inverse association for overall breast cancer diagnosed age ≥40. Further research on pregnancy hormones and risk of steroid receptor-negative cancers is needed to further characterize this association.

Human chorionic gonadotropin (hCG) is necessary for the maintenance of early pregnancy and promotes normal breast cell differentiation. Administered hCG reduces risk of carcinogen-induced breast cancer in animal models, and higher circulating hCG concentrations were associated with significantly lower long-term risk of breast cancer in a prior nested case-control study. In this study, we investigated early-pregnancy hCG concentrations and subsequent breast cancer risk. We conducted a nested case-control study with 1,191 cases and 2,257 controls (matched on age and date at blood collection) in the Finnish Maternity Cohort, a cohort with serum samples from 98% of pregnancies registered in Finland since 1983. This study included women with a serum sample collected early (<140 days gestation) in their first pregnancy resulting in a live, term birth. Breast cancer cases were identified via the Finnish Cancer Registry. Age at breast cancer diagnosis ranged from 22 to 58 years (mean: 41 years). hCG was measured using a solid-phase competitive chemiluminescence assay. Odds ratios (OR) were calculated using conditional logistic regression. We observed no association between hCG and breast cancer risk, overall [Quartile 4 vs. 1, OR, 1.14; 95% confidence interval (CI), 0.94-1.39], by estrogen and progesterone receptor status, or by ages at first-term birth or diagnosis. Associations did not differ by time between pregnancy and diagnosis (e.g., <5 years, ORQ4 vs. Q1, 1.10; 95% CI, 0.64-1.89; ≥15 years, ORQ4 vs. Q1, 1.36; 95% CI, 0.86-2.13; pheterogeneity = 0.62). This large prospective study does not support an inverse relationship between early pregnancy serum hCG concentrations and breast cancer risk. 

Phosphatidylethanol (PEth) is a recently introduced biomarker with high specificity, high sensitivity, and response correlating with alcohol consumption. It has the potential to be a valuable biomarker in population studies on the health effects of alcohol, however its stability in long-term stored blood is not known. We used LCMS/MS to assess the stability of PEth-16:0/18:1 in blood samples (packed erythrocytes) that were stored between 1 and 19 years at -80 degrees C in a biobank from a large population survey. The participants answered a lifestyle questionnaire that included questions on alcohol consumption. For analysis, we selected blood samples from seven homogenous ethanol consumption cohorts collected at intervals from 1997 to 2015. Despite the narrow stated alcohol consumption range, 10-15 g/day, there were large differences in PEth values between individuals in the cohorts, from below the limit of detection of 0.005 mu mol/L to 1.40 mu mol/L. The median was 0.08 mu mol/L. Neither generalized linear modeling, nor principal component analysis revealed a statistically significant association between time of storage and PEth levels. The PEth results indicate that the participants had, on average, under-reported their alcohol consumption several-fold. The findings suggest that PEth in blood has a sufficient long-term stability for use as an alcohol biomarker in prospective case-control studies. Analysis of blood stored in biobanks could significantly improve the validity of assessments exploring the health effects of alcohol.

Testing for drugs-of-abuse in urine is requested for multiple reasons, including legal and workplace policies. Two cases were studied in which there was a suspicion that the patients continued to abuse diazepam, because of repeatedly positive urine samples. In these cases, diazepam metabolites were measured in urine samples by gas or liquid chromatography coupled to mass spectrometry. The concentrations of diazepam metabolites were subsequently creatinine correlated. Very long elimination times were found in the described cases. None of them had in fact ingested diazepam again during the study period. By the use of pharmacogenetic typing, one of the subjects was found to have a slow metabolism for CYP2C9 as well as for CYP2C19. In the second case, there was a possible drug interaction between diazepam and zolpidem.

Pregnancy reduces maternal risk of breast cancer in the long term, but the biological determinants of the protection are unknown. Animal experiments suggest that estrogens and progesterone could be involved, but direct human evidence is scant. A case-control study (536 cases and 1,049 controls) was nested within the Finnish Maternity Cohort. Eligible were primiparous women who delivered at term a singleton offspring before age 40. For each case, two individually matched controls by age (+/- 6 months) and date of sampling (+/- 3 months) were selected. Estradiol, estrone and progesterone in first-trimester serum were measured by high-performance liquid chromatography tandem mass spectrometry and sex-hormone binding globulin (SHBG) by immunoassay. Odds ratios (OR) and 95% confidence intervals (CI) were estimated through conditional logistic regression. In the whole study population there was no association of breast cancer with any of the studied hormones. In analyses stratified by age at diagnosis, however, estradiol concentrations were positively associated with risk of breast cancer before age 40 (upper quartile OR, 1.81; CI, 1.083.06), but inversely associated with risk in women who were diagnosed =age 40 (upper quartile OR, 0.64; CI, 0.401.04), pinteraction 0.004. Risk estimates for estrone mirrored those for estradiol but were less pronounced. Progesterone was not associated with risk of subsequent breast cancer. Our results provide initial evidence that concentrations of estrogens during the early parts of a primiparous pregnancy are associated with maternal risk of breast cancer and suggest that the effect may differ for tumors diagnosed before and after age 40.

Differentiating between Parkinson’s disease (PD) and the atypical Parkinsonian disorders of multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) is difficult clinically due to overlapping symptomatology, especially at early disease stages. Consequently, there is a need to identify metabolic markers for these diseases and to develop them into viable biomarkers. In the present investigation, solution nuclear magnetic resonance and mass spectrometry metabolomics were used to quantitatively characterize the plasma metabolomes (a total of 167 metabolites) of a cohort of 94 individuals comprising 34 PD, 12 MSA, and 17 PSP patients, as well as 31 control subjects. The distinct and statistically significant differences observed in the metabolite concentrations of the different disease and control groups enabled the identification of potential plasma metabolite markers of each disorder and enabled the differentiation between the disorders. These group-specific differences further implicate disturbances in specific metabolic pathways. The two metabolites, formic acid and succinate, were altered similarly in all three disease groups when compared to the control group, where a reduced level of formic acid suggested an effect on pyruvate metabolism, methane metabolism, and/or the kynurenine pathway, and an increased succinate level suggested an effect on the citric acid cycle and mitochondrial dysfunction.

Well-established associations between reproductive characteristics and epithelial ovarian cancer (EOC) support an involvement of sex steroid hormones in the etiology of EOC. Limited previous studies have evaluated circulating androgens and the risk of EOC, and estrogens and progesterone have been investigated in only one of the previous studies. Furthermore, there is little data on potential heterogeneity in the association between circulating hormones and EOC by histological subgroup. Therefore, we conducted a nested case-control study within the Finnish Maternity Cohort and the Northern Sweden Maternity Cohort to investigate the associations between circulating pre-diagnostic sex steroid concentrations and the histological subtypes of EOC. We identified 1052 EOC cases among cohort members diagnosed after recruitment (1975-2008) and before March 2011. Up to three controls were individually matched to each case (n=2694). Testosterone, androstenedione, 17-hydroxyprogesterone (17-OHP), progesterone, estradiol (E-2), and sex hormone-binding globulin levels were measured in serum samples collected during the last pregnancy before EOC diagnosis. We used conditional logistic regression to estimate odds ratios (ORs) and 95% CIs. Associations between hormones and EOC differed with respect to tumor histology and invasiveness. Sex steroid concentrations were not associated with invasive serous tumors; however, doubling of testosterone and 17-OHP concentration was associated with approximately 40% increased risk of borderline serous tumors. A doubling of androgen concentrations was associated with a 50% increased risk of mucinous tumors. The risk of endometrioid tumors increased with higher E-2 concentrations (OR: 1.89 (1.20-2.98)). This large prospective study in pregnant women supports a role of sex steroid hormones in the etiology of EOC arising in the ovaries.

Evidence suggests that the hormonal milieu of pregnancy is an important determinant of subsequent cancer and other chronic diseases in both the mother and the offspring. How well a single blood specimen collected during a pregnancy characterizes exposure to these hormones throughout gestation, and also in subsequent pregnancies, is not well understood. We used serial serum samples from 71 pregnant women (25 primiparous, 25 biparous, and 21 with 2 consecutive pregnancies) with natural, complication-free pregnancies and a healthy offspring at term who participated in a population-based screening trial for congenital infections in Finland between January 1st, 1988 and June 30, 1989 and provided a blood sample in each trimester. Hormone levels were more strongly correlated between consecutive trimesters of a pregnancy than between the 1st and 3rd trimester (e.g. estradiol, 1st vs. 2nd and 2nd vs. 3rd trimester r=0.51 and r=0.60, p<0.01; 1st vs. 3rd trimester r=0.32, p<0.05). Concentrations of sRANKL remained stable throughout gestation, whereas estradiol, estrone, progesterone, testosterone, prolactin, and osteoprotegerin increased throughout pregnancy. First trimester hormone concentrations explained less of the variation in the third trimester on their own than second trimester hormone levels (e.g. estradiol R²T1=16% and R²T2=42%). Addition of maternal (e.g., smoking) and/or child characteristics (e.g., sex) improved the accuracy of the 3rd trimester estimates for some of the hormones. In conclusion, one hormone measurement in early pregnancy, in conjunction with maternal and fetal characteristics, permits estimation of 3rd trimester hormone concentrations.

Background: Evidence suggests that the hormonal milieu of pregnancy is an important determinant of subsequent cancer and other chronic diseases in both the mother and the offspring. Many of the existing maternity and birth cohorts include specimens drawn only once during pregnancy. How well a single blood specimen collected during a pregnancy characterizes exposure to these hormones throughout gestation, and also in subsequent pregnancies, is not well understood.

Methods: We used serial serum samples from 71 pregnant women (25 primiparous, 25 multiparous, and 21 with two consecutive pregnancies) with natural, complication-free pregnancies and a healthy offspring at term who participated in a population-based screening trial for congenital infections in Finland between January 1st, 1988 and June 30, 1989 and provided a blood sample in each trimester.

Results: Hormone levels were more strongly correlated between consecutive trimesters of a pregnancy than between the 1st and 3rd trimester (e.g., estradiol, r(T1 vs. T2) = 0.51 and r(T2 vs. T3) = 0.60, p < 0.01; r(T1 vs. T3) = 0.32, p < 0.05). Concentrations of sRANKL remained stable throughout gestation, whereas estradiol, estrone, progesterone, testosterone, prolactin, and osteoprotegerin increased throughout pregnancy. First trimester hormone concentrations explained less of the variation in the third trimester on their own than second trimester hormone levels (e.g. estradiol R-T1(2) = 16 % and R-T2(2) = 42 %). Addition of maternal (e.g., smoking) and/or child characteristics (e.g., sex) improved the accuracy of the 3rd trimester estimates for some of the hormones.

Conclusions: One hormone measurement in early pregnancy, in conjunction with maternal and fetal characteristics, permits estimation of 3rd trimester hormone concentrations. Therefore, single hormone measurements available from maternity cohorts are suitable to quantify hormone exposure during pregnancy. To our knowledge, we provide the first data on correlations between hormone concentrations both across trimesters of a single pregnancy, as well as between two subsequent pregnancies.

BACKGROUND: Vitamin D may influence circulating levels of sex steroid hormones in women during reproductive life, but associations in pregnant women have not been explored.

METHODS: Correlation and linear regression models were used to assess the association between sex steroids, (estradiol, progesterone, 17-hydroxyprogesterone, testosterone, and androstenedione), IGF-1, and serum 25-hydroxyvitamin D (25-OHD) concentrations during the first trimester of pregnancy in 106 cancer-free women from the Finnish Maternity Cohort.

RESULTS: There was no significant association of serum 25-OHD with any of the hormones measured. One-unit increase in serum 25-OHD concentration was associated with a non-significant 6% increase in estradiol concentrations. Multiparous women had higher levels of vitamin D (40.4 vs. 32.9 nmol/L, p-value = 0.01) than primiparous women.

CONCLUSION: Our study does not support an association between maternal serum 25-OHD levels and sex steroids or IGF-I concentrations during the first trimester of pregnancy.