147 research outputs found

    The interplay between hormones, lipids, and dietary intake: the BioCycle study

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    Background: Exogenous estrogens (i.e. hormone therapy and oral contraceptives) have been shown to affect the lipid profile, leading to the hypothesis that endogenous estrogens may have similar effects. However, the relationship between estrogens and lipoproteins is complex, especially given that cholesterol is the initial precursor for steroid biosynthesis and dyslipidemia has been associated with altered hormone levels and anovulation. The effects of baseline cholesterol levels on anovulation are also not well understood. As fiber intake lowers both estrogen and lipoproteins, it is unknown whether estrogen may mediate the effect of fiber among premenopausal women. Methods: The BioCycle study was a prospective cohort of 250 self-reported regularly menstruating women aged 18 to 44, followed for two menstrual cycles. Lipoprotein cholesterol and hormones were measured in serum collected at up to 16 visits timed using fertility monitors. Marginal structural models with inverse probability of exposure weights were used to model the associations of interest. Results: Estradiol was positively associated with HDL cholesterol in acute effects models, and inversely associated with total and LDL cholesterol and triglycerides in persistent effects models. Total cholesterol levels preceding the predicted time of ovulation were weakly associated with an increased risk of anovulation, and luteinizing hormone:follicle-stimulating hormone ratio, sex hormone binding-globulin, insulin, and acne were identified as significant predictors of anovulation. Fiber consumption at or above 22 g/day was associated with lower total and LDL cholesterol, independent of estrogen, however the controlled direct effect was reduced at high levels of estrogen. Conclusions: Our results support the hypothesis that estrogen exerts beneficial effects on lipoprotein cholesterol levels and sheds light into the timing of these effects. The more atherogenic lipid profile and endocrine characteristics indicative of hyperandrogenism among anovulatory women are indicative of a mild undiagnosed phenotype of polycystic ovary syndrome, however further research is needed to elucidate the biological mechanisms. The reduced controlled direct effects of fiber on cholesterol at higher estrogen levels suggest that estrogen decreases fiber's effect among premenopausal women. Cycle phase should be considered in the design and interpretation of studies in women of reproductive age due to estrogen's influence on many biological processes

    Preconception care: it’s never too early

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    The preconception window has been recognized as one of the earliest sensitive windows of human development, and interventions that focus on this period have the potential to affect not only pregnancy but long term outcomes as well. The journal Reproductive Health has published a supplement entitled ‘Preconception Interventions’ which includes a series of systematic reviews regarding the impact of public health interventions during the preconception period on maternal and child health. These articles describe the role that poor preconception health plays in creating health disparities across the globe. The reviews highlight our current understanding (or lack thereof) regarding how both maternal and paternal preconception health and knowledge shapes the long-term health of not only children, but of families, communities, and nations. Researchers and healthcare workers should take particular note of these interventions, as the preconception time period may be as important as the pregnancy and post-pregnancy periods, and is critical in terms of bridging the gap in the continuum of care, particularly for adolescents.Fil: Mumford, Sunni L.. National Institutes of Health; Estados UnidosFil: Michels, Kara A.. National Institutes of Health; Estados UnidosFil: Salaria, Natasha. BioMed Central; Reino UnidoFil: Valanzasca, Pilar. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Belizan, Jose. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Dietary Restraint and Gestational Weight Gain

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    To determine whether a history of preconceptional dieting and restrained eating was related to higher weight gains in pregnancy

    The Association between a Medical History of Depression and Gestational Diabetes in a Large Multi-ethnic Cohort in the United States

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    Background: Both major depression and gestational diabetes mellitus (GDM) are prevalent among women of reproductive age. Our objective was to determine whether a medical history of depression is related to subsequent development of GDM. Methods: The Consortium on Safe Labor was a US retrospective cohort study of 228 562 births between 2002 and 2008. Exclusion criteria for the present analysis included multiple gestation pregnancies (n = 5059), pre-existing diabetes (n = 12 771), deliveries(n = 395), site GDM prevalence ( Results: The final analytic population included 121 260 women contributing 128 295 pregnancies, of which 5606 were affected by GDM. A history of depression was significantly associated with an increased risk of developing GDM (multivariate odds ratio [aOR] = 1.42 [95% confidence interval (CI) 1.26, 1.60]). Adjusting for pre-pregnancy BMI and weight gain during pregnancy attenuated the association, although it remained statistically significant (aOR = 1.17 [95% CI 1.03, 1.33]). Conclusions: A history of depression was significantly associated with an increased GDM risk among a large multi-ethnic US cohort of women. If the association is confirmed, depression presents a potentially modifiable risk factor of GDM and provides additional clues to the underlying pathophysiology of GDM

    Imputation approaches for potential outcomes in causal inference

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    Background: The fundamental problem of causal inference is one of missing data, and specifically of missing potential outcomes: if potential outcomes were fully observed, then causal inference could be made trivially. Though often not discussed explicitly in the epidemiological literature, the connections between causal inference and missing data can provide additional intuition

    Effect of Dietary Fiber Intake on Lipoprotein Cholesterol Levels Independent of Estradiol in Healthy Premenopausal Women

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    High-fiber diets are associated with improved lipid profiles. However, pre- and postmenopausal women respond differently to fiber intake, suggesting that endogenous estradiol mediates the effect. The authors' objective was to determine the direct effect of fiber intake on lipoprotein cholesterol levels independent of estradiol among premenopausal women. The BioCycle Study, a prospective cohort study conducted at the State University of New York at Buffalo from 2005 to 2007, followed 259 healthy women for up to 2 complete menstrual cycles. Serum lipoprotein and hormone levels were measured at 16 visits timed using fertility monitors. Fiber intake was assessed by 8 24-hour recalls. Marginal structural models with inverse probability weights for both lipoprotein and estradiol levels were used to estimate controlled direct effects of the highest category of fiber intake (≥22 g/day vs. <22 g/day) while accounting for age, body mass index, total energy, vitamin E intake, physical activity, luteinizing hormone, follicle-stimulating hormone, and progesterone. Reductions were observed in total and low density lipoprotein cholesterol in women with higher fiber intakes. Direct effects were greater than total effects. These analyses suggested that estradiol mediates at least part of the association between fiber and cholesterol among premenopausal women. More research is needed to elucidate the biologic mechanisms driving these associations
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