Environmental and genetic predictors of whole blood mercury and selenium concentrations in pregnant women in a UK birth cohort.

There is evidence that tissue concentrations of mercury (Hg) and selenium (Se) are predicted by numerous dietary, sociodemographic, environmental, and genetic factors. This study aimed to estimate the relative importance of predictors of Hg and Se concentrations in blood samples taken from pregnant women. The Avon Longitudinal Study of Parents and Children (ALSPAC) in the UK measured whole blood Hg and Se concentrations in 3,972 pregnant women. We identified 30 potential predictors of Hg and 24 of Se, which were evaluated using cross-validated random forests to identify the optimal models for predictive power. The relative importance of individual variables was estimated by averaging the added-R2 per predictor. Linkage disequilibrium score regression was used to estimate the variance explained by genotype. A multivariable model of 14 predictors explained 22.4% of Hg variance (95% CI: 13.0 to 37.1), including 6.9% from blood Se and 3.2% from white fish consumption. There were 11 predictors which explained 15.3% of Se variance (CI: 8.9 to 25.9), including 6.4% from blood Hg, 1.3% from blood lead, and 1.3% from oily fish. Measured genetic variation explained 30% of Hg variance (CI: 8.4 to 51.5) and 37.5% of Se (CI: 10.4 to 64.5). A high proportion of Hg and Se variance could be explained from dietary, sociodemographic, metabolic, and genetic factors. Seafood consumption was less predictive of Hg than may be expected and other factors should be considered when determining risk of exposure. There was tentative evidence that genotype is a major contributor to Hg and Se variation, possibly by modifying the efficacy of internal metabolism.

The dietary approaches to stop hypertension (DASH) dietary pattern in childhood in relation to cardiometabolic risk in adolescence and early adulthood in the ALSPAC birth cohort.

OBJECTIVE: To investigate the relationship between the dietary approaches to stop hypertension (DASH)-style dietary patterns in childhood and cardiometabolic risk (CMR) in adolescence/early adulthood. DESIGN: Data were obtained from the Avon Longitudinal Study of Parents and Children (ALSPAC) prospective cohort. Diet diary data collected at 7, 10 and 13 years were used to calculate DASH-style diet scores (DDS). Multivariable linear regression models were used to investigate the associations between the DDS at 7, 10 and 13 years and CMR scores, calculated at 17 and 24 years. SETTING: The ALSPAC cohort included children born in south-west England in 1991-1992. PARTICIPANTS: Children with complete dietary, covariate and cardiometabolic data at 17 (n 1,526) and 24 years (n 1,524). RESULTS: A higher DDS at 7 and 10 years was negatively associated with CMR scores at 17 years (ß = -0·64 (95 % CI -1·27, -0·006), Ptrend=0·027 for fifth v. first DDS quintile at 7 years; ß = -0·73 (95 % CI -1·35, -0·12) and Ptrend=0·037 for fifth v. first DDS quintile at 10 years) and at 24 years (ß = -0·92 (95 % CI -1·49, -0·34) Ptrend = 0·001 for fifth v. first DDS quintile at 7 years; ß = -0·60 (95 % CI -1·20, -0·05) Ptrend = 0·092 for fifth v. first DDS quintile at 10 years). No associations were found between the DDS at 13 years and CMR score at 17 and 24 years. CONCLUSION: Greater adherence with a DASH-style diet during childhood was associated with better cardiometabolic health in adolescence/adulthood in the ALSPAC cohort. The components of the DASH diet could be recommended to improve children's cardiometabolic health.

Adherence to the national guidance on foods and drinks to limit or avoid during pregnancy in England: the PEAR Study.

OBJECTIVE: The National Health Service (NHS) England website provides guidance on foods/drinks to avoid or limit during pregnancy because of microbiological, toxicological or teratogenic hazards. The aims were to determine adherence and whether demographic characteristics were associated with adherence. DESIGN: Cross-sectional study. SETTING: Online survey of postpartum women resident in England during pregnancy. PARTICIPANTS: Recently, postpartum women resident in England during their pregnancy (n 598; median age 33 (IQR 30-36) years) completed an online questionnaire (April-November 2022). Questions included those on consumption of twenty-one food/drink items that the NHS advises pregnant women to avoid/limit. The study is part of the Pregnancy, the Environment And nutRition (PEAR) Study. Summary statistics were used to determine proportions adhering to the guidance. Adjusted logistic regression was used to model the associations of adherence with demographic characteristics. RESULTS: Adherence was generally high (>90 % for eight of ten food/drink items to be avoided). However, among pre-pregnancy consumers, several items were not completely avoided, for example, 81 % (128/158) for game meat/gamebirds, 37 % (176/478) for cured meats and 17 % (81/467) for soft cheeses. Greater educational attainment (e.g. caffeinated soft drinks OR 2·25 (95 % CI 1·28, 3·94)), greater maternal age (e.g. oily fish 1·64 (1·05, 2·56)) and lower parity (e.g. caffeinated coffee 0.28 (0.11, 0.69)) were the most usual characteristics associated with adherence. CONCLUSION: Evidence of concerning levels of non-adherence for some food/drink items suggests a case for more education on some of the guidance, particularly for women with lower educational attainment, greater parity and greater maternal age. Further research on barriers to the implementation of the guidance is needed.

Associations of childhood diet quality scores with arterial stiffness and carotid artery intima-media thickness in adolescence/early adulthood: findings from the ALSPAC cohort.

This study examined the relationship between childhood diet quality and arterial stiffness and thickness during adolescence/early adulthood. Participants were from the Avon Longitudinal Study of Parents and Children (ALSPAC) with dietary data at ages 7, 10 and 13 years and pulse wave velocity (PWV) and carotid intima-media thickness (cIMT) at ages 17 and/or 24 years. Diet quality (DQ) was assessed using five scores: a children's Mediterranean-style diet (C-rMED) Z-score, a children's Dietary Inflammatory Z-score (C-DIS), a DASH diet Z-score, a children's Eatwell Guide (C-EWG) Z-score reflecting UK dietary guidelines and a data-driven obesogenic Z-score. Adjusted regression models examined the associations between DQ scores at 7-13 years and PWV and cIMT at 17 and 24 years. In adjusted models, a high v. low Obesogenic Z-score at 7 and 10 years was associated with higher PWV at 17: ß 0.07 (95 % CI 0.01, 0.13) and ß 0.10 (95 % CI 0.04, 0.16), respectively. A high v. low C-rMED Z-score at 7 years was associated with lower PWV at 17 (ß -0.07; 95 % CI -0.14, -0.01). A high (more anti-inflammatory) vs low C-DIS Z-score at 10 years was associated with a lower PWV at 17 years: ß -0.06 (95 % CI -0.12, -0.01). No other associations were observed. In conclusion, an Obesogenic dietary pattern in childhood (7-10 years) was related to increased arterial stiffness, while Mediterranean-style and anti-inflammatory diets were related to decreased arterial stiffness in adolescence. This highlights the importance of establishing healthy dietary habits early in life to protect against vascular damage.

Genome-Wide Association Study of Blood Mercury in European Pregnant Women and Children.

Mercury has high industrial utility and is present in many products, and environmental contamination and occupational exposure are widespread. There are numerous biological systems involved in the absorption, metabolism, and excretion of Hg, and it is possible that some systems may be impacted by genetic variation. If so, genotype may affect tissue concentrations of Hg and subsequent toxic effects. Genome-wide association testing was performed on blood Hg samples from pregnant women of the Avon Longitudinal Study of Parents and Children (n = 2893) and children of the Human Early Life Exposome (n = 1042). Directly-genotyped single-nucleotide polymorphisms (SNPs) were imputed to the Haplotype Reference Consortium r1.1 panel of whole genotypes and modelled againstlog-transformed Hg. Heritability was estimated using linkage disequilibrium score regression. The heritability of Hg was estimated as 24.0% (95% CI: 16.9% to 46.4%) in pregnant women, but could not be determined in children. There were 16 SNPs associated with Hg in pregnant women above a suggestive p-value threshold (p < 1 × 10-5), and 21 for children. However, no SNP passed this threshold in both studies, and none were genome-wide significant (p < 5 × 10-8). SNP-Hg associations were highly discordant between women and children, and this may reflect differences in metabolism, a gene-age interaction, or dose-response effects. Several suggestive variants had plausible links to Hg metabolism, such as rs146099921 in metal transporter SLC39A14, and two variants (rs28618224, rs7154700) in potassium voltage-gated channel genes. The findings would benefit from external validation, as suggestive results may contain both true associations and false positives.

Net effects explains the benefits to children from maternal fish consumption despite methylmercury in fish.

In 2001 the U.S. Food and Drug Administration (FDA) issued precautionary advice to pregnant women to limit fish consumption over concern that the methylmercury content might harm their children's neurodevelopment. This concern was based largely on results from an epidemiological study of mothers primarily exposed to methylmercury from consuming pilot whale. Subsequently, FDA and the World Health Organization/Food and Agriculture Organization (WHO/FAO) undertook independent assessments of fish consumption that considered net effects from both fish nutrients, primarily omega-3 fatty acids, as beneficial and methylmercury as harmful. Both assessments estimated that when mothers regularly consume fish during pregnancy, their children are likely to have improved neurodevelopment compared to children of non-fish eaters despite their exposure to methylmercury. These estimated improvements included gains of two to over five full scale IQ points from levels of maternal consumption that are achievable in most of the world. Consistent with those estimates, human research on fish consumption and child neurodevelopment from more than 200,000 mother-child pairs now collectively reports 51 beneficial associations with neurodevelopmental outcomes and three adverse associations, the latter with no discernable pattern. These associations include full scale IQ gains similar to, or somewhat higher than, those estimated by FDA and FAO/WHO. Also consistent with the FDA and FAO/WHO estimates, research has reported beneficial associations with fish consumption when pregnant women are exposed to methylmercury from fish in excess of the U.S. Environmental Protection Agency's (EPA) Reference Dose (RfD). Our analysis evaluates how the net effects approach as utilized by FDA and FAO/WHO provides a holistic explanation for these results with implications for public health policy. This concordance of net effects modeling and empirical scientific evidence supports a clarification of current public health recommendations to focus on greater fish consumption by pregnant women for their children's neurodevelopment.

Fish Consumption during Pregnancy in Relation to National Guidance in England in a Mixed-Methods Study: The PEAR Study.

Guidance on foods to limit or avoid in pregnancy is provided on the NHS website for England. Advice on fish consumption is related to exposure to mercury, dioxins and polychlorinated biphenyls, which may have adverse effects on fetal neurodevelopment. Our aim was to provide evidence on the effectiveness of the guidance in minimising exposure to toxins while maximising nutrient intake in a mixed-methods study. An online questionnaire on fish consumption before/during pregnancy was completed by postpartum women (≤12 months) in England (n = 598). A subsample of participants was invited to take part in an interview (n = 14). Women who ate fish before pregnancy reduced their intakes of both oily and white fish during pregnancy, with some avoiding it altogether. Women did not exceed the limit on tinned tuna, but there was evidence of mis-recall on the suggested limit. Overall intakes of fish were below that recommended during pregnancy (36% compliance for pre-pregnancy consumers). Barriers to fish consumption included risk aversion, confusion over specific details of the guidance, cost, availability, family preferences and smell/taste. Clarity and simplicity of the NHS guidance, with an overall message on the number of portions of fish a week advised prominently shown, would help pregnant women to benefit from the nutrients in fish while minimising exposure to toxins. The guidance on the number of cans of tuna advised per week is poorly recalled and needs to be disseminated accurately. The guidance on shark/marlin/swordfish could receive less prominence as it is rarely eaten by pregnant women in England.

Prospective association between adherence to UK dietary guidelines in school-age children and cardiometabolic risk markers in adolescence/early adulthood in the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort.

Research into how alignment to UK dietary guidelines during childhood affects cardiometabolic health is limited. The association between adherence to UK dietary guidelines during childhood and overall cardiometabolic risk (CMR) in adolescence/early adulthood was explored using data from the Avon Longitudinal Study of Parents and Children (ALSPAC). ALSPAC children with diet diaries completed at 7, 10 and 13 years of age, and data on CMR markers at 17 years (n 1940) and 24 years (n 1957) were included. A children's Eatwell Guide (C-EWG) score was created by comparing dietary intakes at each age to UK dietary guidelines for nine foods/nutrients. Cardiometabolic health at 17 and 24 years was assessed using a composite CMR score. Multivariable linear regression models examined associations between C-EWG scores at 7, 10 and 13 years and the CMR score at 17 and 24 years, adjusting for confounders. C-EWG scores were generally low. However, a higher score (adherence to more dietary guidelines) at 7 years old was associated with a lower CMR score at 17 and 24 years: ß -0·13 (95 % CI -0·25, -0·01) and ß -0·25 (95 % CI -0·38, -0·13) for a 1-point increase in C-EWG score, respectively. A higher C-EWG score at 10 years was also associated with a lower CMR z-score at 24 years. No clear associations were evident at other ages. Greater adherence to UK dietary guidelines during mid-childhood was associated with a better overall cardiometabolic profile, suggesting that encouraging children to eat in this way has long-term benefits to health.

Provision of information by midwives for pregnant women in England on guidance on foods/drinks to avoid or limit.

BACKGROUND: The National Health Service (NHS) website gives guidance for pregnant women in England on foods/drinks to avoid or limit because of microbiological, toxicological or teratogenic hazards. These include, for example, some types of soft cheeses, fish/seafood and meat products. This website and midwives are trusted sources of information for pregnant women, but the ways in which midwives can be supported to provide clear and accurate information are unknown. AIMS: The aims were to: (1) determine midwives' accuracy of recall of information and confidence in delivering the guidance to women; (2) identify barriers to provision; (3) identify the ways in which midwives provide this information to women. METHODS: Registered Midwives practicing in England completed an online questionnaire. Questions included those on what information they provided and their confidence in delivering it, the ways they provided information on foods to avoid/limit, their recall of some of the guidance, and what resources they used. Ethics approval was given by the University of Bristol. RESULTS: More than 10% of midwives (n = 122) were 'Not at all confident/Don't know' in providing advice about ten items, including game meat/gamebirds (42% and 43%, respectively), herbal teas (14%) and cured meats (12%). Only 32% correctly recalled overall advice on eating fish, and only 38% the advice on tinned tuna. The main barriers to provision were lack of time in appointments and lack of training. The most usual methods of disseminating information were verbal (79%) and signposting to websites (55%). CONCLUSION: Midwives were often unconfident about their ability to provide accurate guidance, and recall on items tested was frequently mistaken. Delivery of guidance by midwives on foods to avoid or limit needs to be supported by appropriate training and access to resources, and sufficient time in appointments. Further research on barriers to the delivery and implementation of the NHS guidance is needed.

Effect of being a persistent picky eater on feeding difficulties in school-aged children.

Children who are picky eaters often develop feeding difficulties during preschool years. These difficulties may persist into adolescence in some children. The study aim was to examine feeding difficulties and maternal feeding strategies longitudinally from age 5.5-8.5 years in relation to persistent picky eating. Picky eating behaviour in children enrolled in the Avon Longitudinal Study of Parents and Children was assessed using questionnaires between 2 and 5.5 years of age. Feeding behaviours were evaluated using questionnaires between 5.5 and 8.5 years. Data were analysed using adjusted logistic regression models. Of the 7405 children with data on picky eating 1926 (26%) were classified as never picky eaters, 385 (5%) were non-persistent picky eaters and 564 (8%) were persistent picky eaters. At 5.5, 7 and 8.5 years both persistent picky eaters and non-persistent picky eaters were more likely than never picky eaters to indicate difficulties in eating what the mother wanted, deliberately eat insufficiently, refuse to eat what was on offer, be choosy, not over-eat, and be difficult to get into routine, but with the likelihood decreasing with age (e.g. in persistent picky eaters vs non-picky eaters: refused to eat offered food OR 44.2 (95% CI 29.1, 67.0) at 5.5 years, 15.5 (11.5, 20.8) at 7 years and 14.1 (10.7, 18.6) at 8.5 years). The families of children who are picky eaters at the time of entering the school system should be offered reassurance that the feeding difficulties are likely to slowly resolve over time.

Adherence to UK dietary guidelines in school-aged children from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort.

Compliance to UK dietary recommendations was assessed in school-aged children from a population-based cohort: the Avon Longitudinal Study of Parents and Children (ALSPAC). A Children's Eatwell Guide (C-EWG) score was developed to assess socio-demographic predictors of meeting dietary recommendations. ALSPAC children with plausible diet diary data at 7 years (n 5373), 10 years (n 4450) and 13 years (n 2223) were included in the study. Their dietary intakes (recorded between 1998 and 2006) were compared with dietary guidelines for total and saturated fats, free sugars, salt, fibre, protein, carbohydrates, fruit and vegetables, non-oily and oily fish and red/processed meat. The C-EWG score (0-9 points) indicated the number of recommendations met at each age. Cross-sectional associations between socio-demographic characteristics and C-EWG scores were assessed using multivariable regression. The lowest adherence to guidelines at 7 years was for sugar (0·1 % meeting recommendations), followed by fibre (7·7 %), oily fish (9·5 %), saturated fat (9·7 %) and fruit and vegetables (15·2 %). Highest adherence was for limiting red/processed meat (67·3 %) and meeting carbohydrate recommendations (77·3 %). At 7 years, 12·1 % of participants failed to meet any of the nine recommendations, 26·9 % met one and 28·2 % met two. Similar patterns were seen at 10 and 13 years. A lower social class and maternal educational attainment and higher maternal BMI were associated with meeting fewer recommendations. Most school-aged children in this cohort did not meet UK dietary recommendations, particularly children from lower socio-economic backgrounds. Additional public health initiatives are needed to improve the quality of UK children's diets, particularly targeting lower socio-economic groups.

The inflammatory potential of the diet in childhood is associated with cardiometabolic risk in adolescence/young adulthood in the ALSPAC birth cohort.

PURPOSE: This study examined the association between a Dietary Inflammatory Score adapted for children (cDIS) and Cardiometabolic Risk (CMR) score in adolescence/early adulthood in the Avon Longitudinal Study of Parents and Children (ALSPAC). METHODS: The cDIS was calculated at 7, 10 and 13 years using diet diary data. Anthropometric and biochemical data at 17 (N = 1937) and 24 (N = 1957) years were used to calculate CMR scores at each age [mean sex-specific z-scores from triacylglycerol, HDL-cholesterol, LDL-cholesterol, mean arterial blood pressure (MAP), homeostatic model assessment of insulin resistance (HOMA-IR) and fat-mass index (FMI)]. Multivariable linear regression models examined associations between cDIS at 7, 10 and 13 years and a continuous CMR z-score and individual CMR markers at 17 and 24 years. RESULTS: In fully adjusted models, a higher cDIS (more pro-inflammatory diet) at 7 years was associated with an increase in CMR z-score at 17 years (ß 0.19; 95% CI 0.03-0.35 for third versus first cDIS tertile) and at 24 years (ß 0.28; 95% CI 0.11,0.44 for third versus first cDIS tertile). There was a weak association between a higher cDIS at 10 years and an increase in CMR z-score at 17 years (ß 0.16; 95% CI - 0.003, 0.32 for third versus first cDIS tertile). No other clear associations were evident. FMI, MAP and HOMA-IR were the main CMR factors contributing to these associations. CONCLUSION: A more pro-inflammatory diet during childhood was associated with a worse cardiometabolic profile in late adolescence/early adulthood. A childhood diet abundant in nutrients with anti-inflammatory properties could help reduce development of CMR factors.

Prenatal Mercury Exposure and Neurodevelopment up to the Age of 5 Years: A Systematic Review.

Neurodevelopmental delays can interfere with children's engagement with the world and further development, and may have negative consequences into adulthood. Mercury is highly toxic and may negatively influence neurodevelopment because it can freely cross the placenta and accumulate in the fetal brain. We searched four publication databases (Embase, PsycINFO, PubMed/MEDLINE, Scopus) for studies examining the relationship between early life mercury exposure and scores on neurodevelopmental performance measures in children aged 0 to 5 years old. Study quality was assessed using the National Institutes of Health (NIH) Quality Assessment Tool. Thirty-two prospective studies were included in the review. Neurodevelopmental performance was measured using 23 different scales, most commonly the Bayley Scales of Infant and Toddler Development (BSID). In most cases, the evidence for an association between mercury and neurodevelopment was weak. There did not appear to be exceptions for particular childhood ages, outcome scales, or mercury levels. The small number of results to the contrary were more likely to be studies which did not meet our high-quality criteria, and could be a consequence of multiple testing, selection bias, or incomplete confounder adjustment. Based on current evidence, dietary mercury exposure during pregnancy is unlikely to be a risk factor for low neurodevelopmental functioning in early childhood.

Prenatal Mercury Exposure and Infant Weight Trajectories in a UK Observational Birth Cohort.

Mercury is highly toxic metal found in trace quantities in common foods. There is concern that exposure during pregnancy could impair infant development. Epidemiological evidence is mixed, but few studies have examined postnatal growth. Differences in nutrition, exposures, and the living environment after birth may make it easier to detect a negative impact from mercury toxicity on infant growth. This study includes 544 mother-child pairs from the Avon Longitudinal Study of Parents and Children. Blood mercury was measured in early pregnancy and infant weight at 10 intervals between 4 and 61 months. Mixed-effect models were used to estimate the change in infant weight associated with prenatal mercury exposure. The estimated difference in monthly weight gain was -0.02 kg per 1 standard deviation increase in Hg (95% confidence intervals: -0.10 to 0.06 kg). When restricted to the 10th decile of Hg, the association with weight at each age level was consistently negative but with wide confidence intervals. The lack of evidence for an association may indicate that at Hg levels in this cohort (median 1.9 µg/L) there is minimal biological impact, and the effect is too small to be either clinically relevant or detectable.

Prospective association between a Mediterranean-style dietary score in childhood and cardiometabolic risk in young adults from the ALSPAC birth cohort.

PURPOSE: To investigate the prospective association between a children's relative Mediterranean-style diet score (C-rMED) in childhood and a Cardiometabolic Risk (CMR) score in adolescence/young adulthood in the Avon Longitudinal Study of Parents and Children (ALSPAC). METHODS: A C-rMED was calculated at 7, 10 and 13 years from diet diary data. Anthropometric and biochemical data at 17 (N = 1940) and 24 years (N = 1961) were used to calculate CMR scores (sum of sex-specific log-transformed z-scores from triacylglycerol, HDL cholesterol, LDL cholesterol, mean arterial blood pressure, homeostatic model assessment of insulin resistance (HOMA-IR) and fat mass index (FMI)). Adjusted logistic regression models examined associations between C-rMED (categorical and 2-unit increments) and a high CMR score (≥ 80th percentile) and individual CMR components (≥ 80th percentile). RESULTS: A high C-rMED at 13 was associated with a 32% (OR 0.68 (95% CI: 0.49, 0.94)) decreased adjusted odds of having a high CMR score at 24 years, compared to participants with a low C-rMED. No associations were evident at other ages. Tracking of the C-rMED across the three ages showed a stronger negative association between C-rMED and CMR at 24 years when children had at least two high C-rMED scores from 7 to 13 years (adjusted OR: 0.49, 95% CI: 0.29, 0.85), compared to all low scores. FMI and HOMA-IR were the main CMR components contributing to this association. CONCLUSION: Higher Mediterranean-style diet scores in early adolescence were associated with a better CMR profile in young adults (24 year olds). This underscores the importance of establishing healthy eating habits early in life for future cardiometabolic health.

Association of Nutrition in Early Childhood with Body Composition and Leptin in Later Childhood and Early Adulthood.

OBJECTIVES: Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), this study aimed to replicate the finding of the Etude Longitudinale Alimentation Nutrition Croissance des Enfants (ELANCE) that low fat intake in early childhood was associated with increased adiposity in adulthood. METHODS: Diet was assessed at 8 and 18 months using 3-day food records. Body composition variables were measured at 9 and 17 years, and serum leptin at 9 years. Associations were modelled using adjusted linear regression. RESULTS: In replication analyses, in contrast to ELANCE, there was a positive association between fat intake (% energy) at 18 months and fat mass (FM) at 9 years (B coefficient 0.10 (95% CI 0.03, 0.20) kg, p = 0.005). There was no association with serum leptin. In extended analyses fat intake at 18 months was positively associated with FM in boys (0.2 (0.00, 0.30), p = 0.008) at 9 years but not in girls. Fat intake was positively associated with serum leptin concentration in boys (0.2 (0.1, 0.4) ng/mL, p = 0.011) but not in girls. CONCLUSIONS: Our results did not corroborate the findings from the ELANCE study. A high fat diet in early life may have implications for later childhood and adolescent obesity.

Mercury and Prenatal Growth: A Systematic Review.

The intrauterine environment is critical for healthy prenatal growth and affects neonatal survival and later health. Mercury is a toxic metal which can freely cross the placenta and disrupt a wide range of cellular processes. Many observational studies have investigated mercury exposure and prenatal growth, but no prior review has synthesised this evidence. Four relevant publication databases (Embase, MEDLINE/PubMed, PsycINFO, and Scopus) were systematically searched to identify studies of prenatal mercury exposure and birth weight, birth length, or head circumference. Study quality was assessed using the NIH Quality Assessment Tool, and results synthesised in a narrative review. Twenty-seven studies met the review criteria, these were in 17 countries and used 8 types of mercury biomarker. Studies of birth weight (total = 27) involving populations with high levels of mercury exposure, non-linear methods, or identified as high quality were more likely to report an association with mercury, but overall results were inconsistent. Most studies reported no strong evidence of association between mercury and birth length (n = 14) or head circumference (n = 14). Overall, our review did not identify strong evidence that mercury exposure leads to impaired prenatal growth, although there was some evidence of a negative association of mercury with birth weight.

The relationship between dietary intakes and plasma concentrations of PUFA in school-age children from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort.

An adequate intake of PUFA plays a vital role in human health. Therefore, it is important to assess PUFA intakes in different populations and validate them with biomarkers, but only a few small studies are in paediatric populations. We calculated the dietary intake of PUFA and their main food sources in children and assessed associations between PUFA intakes and plasma proportions. Dietary intakes of 7-year-old children (n 8242) enrolled in the Avon Longitudinal Study of Parents and Children were calculated from the parental-completed FFQ. Plasma PUFA were measured in 5571 children 8 months later, and 4380 children had complete dietary and plasma data. The association between dietary and plasma PUFA proportions was estimated using Spearman's correlation coefficients, quintile cross-classification and Cohen's κ coefficients. Mean total PUFA intake was 13·2 g/d (sd 4·2), contributing 6·5 % of total energy intake; n-6 PUFA contributed 5·2 % and n-3 PUFA 0·7 %. The n-6:n-3 ratio was 7·9:1. Mean intakes of EPA and DHA were 35·7 mg/d and 49·7 mg/d, respectively. Most n-3 and n-6 PUFA intakes were weakly correlated with their respective plasma lipids (0·07 ≤ r ≤ 0·16, P < 0·001). The correlation between dietary and plasma DHA was stronger though (r = 0·34, P < 0·001), supported by a modest level of agreement between quintiles (k = 0·32). The results indicate that the FFQ was able to reasonably rank the long-chain (LC) PUFA, DHA, in this paediatric population. Public health initiatives need to address the suboptimal ratio of n-6:n-3 PUFA and very low n-3 LC-PUFA intakes in school-age children in the UK.

Pre-pregnancy maternal BMI classification is associated with preschool childhood diet quality and childhood obesity in the Avon Longitudinal Study of Parents and Children.

OBJECTIVE: To explore the effect of maternal BMI class pre-pregnancy (overweight/obese v. healthy weight/underweight) on childhood diet quality and on childhood overweight/obesity risk. DESIGN: Dietary data were collected using 3-d parental-completed food records for their children at ages 18 and 43 months. An index of diet quality was derived by classification of food items into core and non-core foods. Adjusted multiple linear regression analyses were used to explore the effect of maternal BMI class on diet quality in their children. SETTING: Avon, UK. PARTICIPANTS: A 10% subsample of the Avon Longitudinal Study of Parents and Children. Nine-hundred and eighty children provided complete dietary data at 18 months and 769 at 43 months. RESULTS: Children with overweight/obese mothers consumed greater amounts of energy from non-core foods than children with healthy weight/underweight mothers (0·20 MJ (48 kcal)/d more at 18 months (P < 0·001); 0·19 MJ (45 kcal)/d more at 43 months (P = 0·008)) in adjusted models. Diet quality deteriorated between 18 and 43 months (children reduced their dietary energy intake from core foods (P < 0·001) and increased intake from non-core foods (P < 0·001)). However, this change was not associated with maternal BMI class in adjusted models. Having an overweight/obese mother was associated with an increased odds of the child being overweight/obese at 43 months (OR 1·74 (1·17, 2·58)). CONCLUSIONS: Children aged 18 and 43 months with overweight/obese mothers are likely to have a poorer quality diet than those with healthy/underweight mothers. Parents should be supported in discouraging the consumption of non-core foods in children at these ages.

Maternal prenatal vitamin B12 intake is associated with speech development and mathematical abilities in childhood.

Deficiencies of many nutrients in pregnancy have adverse effects on fetal brain development with consequent impaired cognitive function in childhood. However, it is unclear whether deficiencies of vitamin B12 prenatally are harmful to the developing fetus. We therefore used the Avon Longitudinal Study of Parents and Children to test the hypothesis that cognitive outcomes in childhood are reduced if their mothers consumed a diet low in vitamin B12 during pregnancy. A detailed exposome analysis was used to identify 9 factors independently associated with low vitamin B12 intake. These were taken into account in each of 26 outcome analyses. Results showed that the children of women with the lowest 10% intake of B12 were at increased risk of poor vocabulary at 24 months, reduced ability at combining words at 38 months, poor speech intelligibility at 6 years, poor mathematics comprehension at school years 4 and 6 (ages 8-9 and 10-11 years), and poor results on the national mathematics tests (age 13). There were no such significant adjusted associations for reading or spelling abilities, or for verbal or full-scale IQ (Intelligence Quotient) at 8 or at 15. Thus, we have confirmed that there are adverse effects on the child's development if the pregnant woman has a low intake of vitamin B12, and we have shown that these are specific to certain speech and mathematical abilities.