Nisreen A. Alwan

Maternal alcohol intake prior to and during pregnancy and risk of adverse birth outcomes: evidence from a British cohort

Background 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 pregnancy.

Dietary iron intake during early pregnancy and birth outcomes in a cohort of British women

BACKGROUND Iron deficiency during pregnancy is associated with adverse birth outcomes, particularly, if present during early gestation. Iron supplements are widely recommended during pregnancy, but evidence of their benefit in relation to infant outcomes is not established. This study was performed in the UK, where iron supplements are not routinely recommended during pregnancy, to investigate the association between iron intake in pregnancy and size at birth. METHODS From a prospective cohort of 1274 pregnant women aged 18–45 years, dietary intake was reported in a 24-h recall administered by a research midwife at 12-week gestation. Dietary supplement intake was ascertained using dietary recall and three questionnaires in the first, second and third trimesters. RESULTS Of the cohort of pregnant women, 80% reported dietary iron intake below the UK Reference Nutrient Intake of 14.8 mg/day. Those reported taking iron-containing supplements in the first, second and third trimesters were 24, 15 and 8%, respectively. Women with dietary iron intake >14.8 mg/day were more likely to be older, have a higher socioeconomic profile and take supplements during the first trimester. Vegetarians were less likely to have low dietary iron intake [odds ratio = 0.5, 95% confidence interval (CI): 0.4, 0.8] and more likely to take supplements during the first and second trimesters. Total iron intake, but not iron intake from food only, was associated with birthweight centile (adjusted change = 2.5 centiles/10 mg increase in iron, 95% CI: 0.4, 4.6). This association was stronger in the high vitamin C intake group, but effect modification was not significant. CONCLUSION There was a positive relationship between total iron intake, from food and supplements, in early pregnancy and birthweight. Iron intake, both from diet and supplements, during the first trimester of pregnancy was higher in vegetarians and women with a better socioeconomic profile.

Development of a UK online 24-h dietary assessment tool: myfood24

Assessment of diet in large epidemiological studies can be costly and time consuming. An automated dietary assessment system could potentially reduce researcher burden by automatically coding food records. myfood24 (Measure Your Food on One Day) an online 24-h dietary assessment tool (with the flexibility to be used for multiple 24 h-dietary recalls or as a food diary), has been developed for use in the UK population. Development of myfood24 was a multi-stage process. Focus groups conducted with three age groups, adolescents (11–18 years) (n = 28), adults (19–64 years) (n = 24) and older adults (≥65 years) (n = 5) informed the development of the tool, and usability testing was conducted with beta (adolescents n = 14, adults n = 8, older adults n = 1) and live (adolescents n = 70, adults n = 20, older adults n = 4) versions. Median system usability scale (SUS) scores (measured on a scale of 0–100) in adolescents and adults were marginal for the beta version (adolescents median SUS = 66, interquartile range (IQR) = 20; adults median SUS = 68, IQR = 40) and good for the live version (adolescents median SUS = 73, IQR = 22; adults median SUS = 80, IQR = 25). Myfood24 is the first online 24-h dietary recall tool for use with different age groups in the UK. Usability testing indicates that myfood24 is suitable for use in UK adolescents and adults.

The relationship between dietary supplement use in late pregnancy and birth outcomes: a cohort study in British women

Please 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;117:821–829.

Maternal iron status in early pregnancy and birth outcomes: insights from the Baby's Vascular health and Iron in Pregnancy study.

Fe deficiency anaemia during early pregnancy has been linked with low birth weight and preterm birth. However, this evidence comes mostly from studies measuring Hb levels rather than specific measures of Fe deficiency. The present study aimed to examine the association between maternal Fe status during the first trimester of pregnancy, as assessed by serum ferritin, transferrin receptor and their ratio, with size at birth and preterm birth. In the Baby VIP (Babys Vascular health and Iron in Pregnancy) study, we recruited 362 infants and their mothers after delivery in Leeds, UK. Biomarkers were measured in maternal serum samples previously obtained in the first trimester of pregnancy. The cohort included sixty-four (18 %) small for gestational age (SGA) babies. Thirty-three babies were born preterm (9 %; between 34 and 37 weeks). First trimester maternal Fe depletion was associated with a higher risk of SGA (adjusted OR 2·2, 95 % CI 1·1, 4·1). This relationship was attenuated when including early pregnancy Hb in the model, suggesting it as a mediator (adjusted OR 1·6, 95 % CI 0·8, 3·2). For every 10 g/l increase in maternal Hb level in the first half of pregnancy the risk of SGA was reduced by 30 % (adjusted 95 % CI 0, 40 %); levels below 110 g/l were associated with a 3-fold increase in the risk of SGA (95 % CI 1·0, 9·0). There was no evidence of association between maternal Fe depletion and preterm birth (adjusted OR 1·5, 95 % 0·6, 3·8). The present study shows that depleted Fe stores in early pregnancy are associated with higher risk of SGA.

Children's exposure to second-hand smoke in the home: a household survey in the North of England.

Exposure of children to second-hand smoke (SHS) leads to increased risk of health and social problems and uptake of smoking in the future. We aimed to assess the prevalence of childrens exposure to SHS in their homes, in a deprived area in the North of England and identify what people thought would help them achieve a smoke-free home (SFH). We performed a cross-sectional survey of 318 households with at least one child aged under 16 years in Beeston Hill, a deprived locality in Leeds, England in June 2008. One hundred and seventy-three households [54%, 95% confidence interval (C.I.) 49-60] had at least one smoker in the house. In 42% (95% C.I. 35-50) of these households (n = 73), smoking took place in the presence of children. The odds of allowing smoking in front of children were 2.2 (95% C.I. 1.1-4.5) times greater in households whose head had less than A-level (national exams at 18 years) or equivalent qualification than in homes with a more qualified head of household. 92% of respondents were aware that SHS has negative effects on childrens health. However, 71% felt more information about health risks to children would help reduce exposure to SHS in the home. Smoking in the presence of children takes place in a relatively high proportion of households with smoker(s), despite media awareness campaigns regarding the dangers of passive smoking launched alongside the recently enforced smoke-free public and workplaces legislation. Specific promotion of SFHs is needed to protect the health of children.

Can a community-based ‘smoke-free homes’ intervention persuade families to apply smoking restrictions at homes?

BACKGROUND Children are commonly exposed to second-hand smoke (SHS). The aim of this study is to evaluate the feasibility, acceptability and outcome of Smoke-Free Homes (SFH), a community-based intervention; and assess potential evaluation methods. METHODS SFH, designed to encourage families to implement smoking restrictions at home, was delivered over a period of 6 months through schools, healthcare settings and community events in Beeston, South Leeds, UK. It was evaluated using baseline and post-implementation surveys, focus group discussions and promise forms follow-up. RESULTS We surveyed 318 households before, and 217 households after, the intervention. The proportion of all surveyed households reporting being completely smoke free significantly increased from 35% [95% confidence interval (CI) 30, 40] at baseline to 68% (95% CI: 61, 74) 6 months post-implementation (P < 0.0001). Ninety per cent of people, followed-up by telephone 3 months after signing SFH promise form, said they were still keeping their promise. Focus group discussions with children and parents conveyed acceptability of the intervention, in particular, the schools element, where children are encouraged to discuss the concept of SFH with the adults in their households. CONCLUSIONS Our study shows that SFH can be implemented effectively and has the potential to improve childrens health through preventing exposure to SHS in the home.

Agreement between an online dietary assessment tool (myfood24) and an interviewer-administered 24-h dietary recall in British adolescents aged 11–18 years

myfood24 Is an online 24-h dietary assessment tool developed for use among British adolescents and adults. Limited information is available regarding the validity of using new technology in assessing nutritional intake among adolescents. Thus, a relative validation of myfood24 against a face-to-face interviewer-administered 24-h multiple-pass recall (MPR) was conducted among seventy-five British adolescents aged 11-18 years. Participants were asked to complete myfood24 and an interviewer-administered MPR on the same day for 2 non-consecutive days at school. Total energy intake (EI) and nutrients recorded by the two methods were compared using intraclass correlation coefficients (ICC), Bland-Altman plots (using between and within-individual information) and weighted κ to assess the agreement. Energy, macronutrients and other reported nutrients from myfood24 demonstrated strong agreement with the interview MPR data, and ICC ranged from 0·46 for Na to 0·88 for EI. There was no significant bias between the two methods for EI, macronutrients and most reported nutrients. The mean difference between myfood24 and the interviewer-administered MPR for EI was -230 kJ (-55 kcal) (95 % CI -490, 30 kJ (-117, 7 kcal); P=0·4) with limits of agreement ranging between 39 % (3336 kJ (-797 kcal)) lower and 34 % (2874 kJ (687 kcal)) higher than the interviewer-administered MPR. There was good agreement in terms of classifying adolescents into tertiles of EI (κ w =0·64). The agreement between day 1 and day 2 was as good for myfood24 as for the interviewer-administered MPR, reflecting the reliability of myfood24. myfood24 Has the potential to collect dietary data of comparable quality with that of an interviewer-administered MPR.

Maternal Iron Status in Pregnancy and Long-Term Health Outcomes in the Offspring.

Iron is an essential micronutrient and is important not only in carrying oxygen but also to the catalytic activity of a variety of enzymes. In the fetus, it is vital to the synthesis of hemoglobin and in brain development. Iron deficiency (ID) anemia in pregnancy is a common problem, even in high-income country settings. Around 50% of pregnant women worldwide are anemic, with at least half of this burden due to ID. Iron supplements are widely recommended and used during pregnancy globally. However, the evidence on the extent of benefit they contribute to the offsprings health is not well established, and their routine use has its side effects and drawbacks. Dietary iron intake is difficult to assess accurately and it is unlikely to be sufficient to meet the demands of pregnancy if women start with inadequate body iron stores at conception. Evidence from experimental animal models suggests that maternal ID during pregnancy is associated with fetal growth restriction, as well as offspring obesity and high blood pressure later in life. The possible biological mechanisms for this observed association may be due to ID-induced changes in placental structure and function, enzyme expression, nutrient absorption, and fetal organ development. However, such evidence is limited in human studies. Prenatal ID in experimental animal models also adversely affected the developing brain structures, neurotransmitter systems, and myelination resulting in acute brain dysfunction during the period of deficiency and persistence of various postnatal neurobehavioral abnormalities as well as persistent dysregulation of some genes into adult life after iron repletion pointing to the possibility of gene expression changes. The evidence from human population studies is limited and heterogeneous and more research is needed in the future, investigating the effects of ID in pregnancy on future offspring health outcomes.

Cohort Profile: The UK Women’s Cohort Study (UKWCS)

Cohort Profile: The UK Women’s Cohort Study (UKWCS) Janet E Cade,* Victoria J Burley, Nisreen A Alwan, Jayne Hutchinson, Neil Hancock, Michelle A Morris, Diane E Threapleton and Darren C Greenwood School of Food Science and Nutrition, Leeds Institute for Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK, Department of Health Sciences, University of York, York, UK, School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, Academic Unit of Primary Care and Population Sciences, Faculty of Medicine, University of Southampton, Southampton, UK and School of Geography, University of Leeds, Leeds, UK