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The relationship between dietary supplement use in late pregnancy and birth outcomes: a cohort study in British women
Full text linkPlease cite this paper as: Alwan N, Greenwood D, Simpson N, McArdle H, Cade J. The relationship between dietary supplement use in late pregnancy and birth outcomes: a cohort study in British women. BJOG 2010; DOI: 10.1111/j.1471-0528.2010.02549.x.Objective To examine the relationship between dietary supplement use during pregnancy and birth outcomes.Design A prospective birth cohort.Setting Leeds, UK.Sample One thousand two hundred and seventy-four pregnant women aged 18201345 years.Methods Dietary supplement intake was ascertained using three questionnaires for the first, second and third trimesters. Dietary intake was reported in a 24-hour dietary recall administered by a research midwife at 8201312 weeks of gestation. Information on delivery details and antenatal pregnancy complications was obtained from the hospital maternity records.Main outcome measures Birthweight, birth centile and preterm birth.Results Reported dietary supplement use declined from 82% of women in the first trimester of pregnancy to 22% in the second trimester and 33% in the third trimester. Folic acid was the most commonly reported supplement taken. Taking any type of daily supplement during any trimester was not significantly associated with size at birth taking into account known relevant confounders. Women taking multivitamin-mineral supplements in the third trimester were more likely to experience preterm birth (adjusted OR = 3.4, 95% CI 1.2, 9.6, P = 0.02).Conclusions Regular multivitamin2013mineral supplement use during pregnancy, in a developed country setting, is not associated with size at birth. However, it appears to be associated with preterm birth if taken daily in the third trimester. The mechanism for this is unclear and our study's findings need confirming by other cohorts and/or trials in developed countries
Iron intake during early pregnancy and birth size: insights revealed through structural equation modelling
Get PDFMaternal alcohol intake up to and during pregnancy and risk of adverse birth outcomes: evidence from a British cohort
No full textBackground High maternal alcohol consumption has been linked to adverse birth outcomes such as small for gestational age and preterm birth, which in turn have been linked to increased risk of development of cardiovascular diseases and type 2 diabetes in adulthood. The UK Department of Health (DH) recommends that pregnant women and those trying to conceive should avoid alcohol and never drink more than 1GÇô2 units once or twice a week. This study aimed to investigate the association between alcohol intake before and during different stages of pregnancy with both birthweight and gestational age. Methods Data were used from the Caffeine and Reproductive Health Study (CARE), a prospective birth cohort that included 1303 low-risk pregnant women aged 18GÇô45 years, recruited from September, 2003, to June, 2006. Questionnaires administered in the first and second trimester and postpartum assessed alcohol consumption before pregnancy and for the three trimesters. Frequency of weekly alcohol consumption was analysed by categories of intake to accord with DH guidelines (Gëñ2 units per week, >2 units per week, and a non-drinking category as the referent) and was related to preterm birth and size at birth, measured as grams and as customised birthweight centile, which takes into account maternal prepregnancy weight, height, parity, ethnicity, gestation, and baby's sex in multivariable linear and logistic regression models. We also adjusted for maternal age, caffeine intake, education, energy intake, and salivary cotinine as a biomarker of smoking status. Only participants with complete data for all variables were included in the analyses, which excluded just under 10% of the sample. All women provided informed consent and the study was approved by the Leeds West Local Research Ethics Committee (ref 03/054). Findings 1153, 1135, 793, and 377 women, respectively, had data available for birth outcomes and alcohol consumption before pregnancy and during the three trimesters. 74% of women before pregnancy and 53% in the first trimester reported alcohol intakes above the DH recommendation. For intakes above 2 units per week compared with non-drinkers, the adjusted differences in birth centile were GêÆ7-À7 (95% CI GêÆ12-À8 to GêÆ2-À6; ptrend=0-À009), GêÆ8-À2 (GêÆ12-À6 to GêÆ3-À7; ptrend=0-À002), and GêÆ6-À4 (GêÆ11-À8 to GêÆ1-À1, ptrend=0-À06) before pregnancy and during trimesters 1 and 2, respectively. The association with small for gestational age and preterm birth was strongest in trimester 1, with adjusted odds ratios of 2-À0 (95% CI 1-À2GÇô3-À4; ptrend=0-À03) and 3-À5 (1-À1GÇô11-À2, ptrend=0-À04), respectively. Women who adhered to the recommendations in the first trimester of 2 units or fewer per week were also at a significantly higher risk of having babies born with lower birthweight (adjusted difference GêÆ98-À5, 95% CI GêÆ170-À9 to GêÆ26-À1; ptrend=0-À007), birth centile (GêÆ5-À8, GêÆ10-À8 to GêÆ0-À7; ptrend=0-À002), and preterm birth (adjusted odds ratio 4-À6, 95% CI 1-À4GÇô14-À7; ptrend=0-À04) compared with non-drinkers. Interpretation The first trimester was the most sensitive period for the association of alcohol with restricted fetal growth. However, this finding could be explained by under-reporting of alcohol intake. Our small sample size in the third trimester did not allow us to detect a change in birthweight, and larger prospective studies that take into account timing of exposure to alcohol are needed. We showed no evident safe level of alcohol consumption in pregnancy, and the safe advice should be to abstain from alcohol when planning to conceive and during pregnancy, particularly during its early stages. Funding The CARE study was supported by a grant from the Food Standards Agency, UK (T01033
Maternal alcohol intake prior to and during pregnancy and risk of adverse birth outcomes: evidence from a British cohort
Full text linkBackground: Evidence is conflicting regarding the relationship between low maternal alcohol consumption and birth outcomes. This paper aimed to investigate the association between alcohol intake before and during pregnancy with birth weight and gestational age and to examine the effect of timing of exposure.
Methods: A prospective cohort in Leeds, UK, of 1303 pregnant women aged 18–45 years. Questionnaires assessed alcohol consumption before pregnancy and for the three trimesters separately. Categories of alcohol consumption were divided into ≤2 units/week and >2 units/week with a non-drinking category as referent. This was related to size at birth and preterm delivery, adjusting for confounders including salivary cotinine as a biomarker of smoking status.
Results: Nearly two-thirds of women before pregnancy and over half in the first trimester reported alcohol intakes above the Department of Health (UK) guidelines of ≤2 units/week. Associations with birth outcomes were strongest for intakes >2 units/week before pregnancy and in trimesters 1 and 2 compared to non-drinkers. Even women adhering to the guidelines in the first trimester were at significantly higher risk of having babies with lower birth weight, lower birth centile and preterm birth compared to non-drinkers, after adjusting for confounders (p<0.05).
Conclusions: We found the first trimester to be the period most sensitive to the effect of alcohol on the developing fetus. Women adhering to guidelines in this period were still at increased risk of adverse birth outcomes. Our findings suggest that women should be advised to abstain from alcohol when planning to conceive and throughout pregnanc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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