To construct a diet score for assessing degree of adherence to a healthy and environmentally friendly New Nordic Diet (NND) and to investigate its association with adequacy of gestational weight gain and fetal growth in a large prospective birth cohort.

Main exposure was NND adherence, categorized as low, medium or high adherence. Main outcomes were adequacy of gestational weight gain, described as inadequate, optimal or excessive according to the 2009 Institute of Medicine guidelines, and fetal growth, categorized as being small, appropriate or large for gestational age. Associations of NND adherence with gestational weight gain and fetal growth were estimated with multinomial logistic regression in crude and adjusted models.

Norway.

Women (n 66 597) from the Norwegian Mother and Child Cohort Study (MoBa).

Higher NND adherence implied higher energy and nutrient intakes, higher nutrient density and a healthier macronutrient distribution. Normal-weight women with high as compared with low NND adherence had lower adjusted odds of excessive gestational weight gain (OR=0·93; 95 % CI 0·87, 0·99; P=0·024). High as compared with low NND adherence was associated with reduced odds of the infant being born small for gestational age (OR=0·92; 95 % CI 0·86, 0·99; P=0·025) and with higher odds of the baby being born large for gestational age (OR=1·07; 95 % CI 1·00, 1·15; P=0·048).

The NND score captures diet quality. Adherence to a regional diet including a large representation of fruits and vegetables, whole grains, potatoes, fish, game, milk and drinking water during pregnancy may facilitate optimal gestational weight gain in normal-weight women and improve fetal growth in general.

To determine adherence to nutritional guidelines by pregnant women in New Zealand and maternal characteristics associated with adherence.

A cohort of the pregnant women enrolled into New Zealand’s new birth cohort study, Growing Up in New Zealand.

Women residing within a North Island region of New Zealand, where one-third of the national population lives.

Pregnant women (n 5664) were interviewed during 2009–2010. An FFQ was administered during the face-to-face interview.

The recommended daily number of servings of vegetables and fruit (≥6) were met by 25 % of the women; of breads and cereals (≥6) by 26 %; of milk and milk products (≥3) by 58 %; and of lean meat, meat alternatives and eggs (≥2) by 21 %. One in four women did not meet the recommendations for any food group. Only 3 % met all four food group recommendations. Although adherence to recommendation for the vegetables/fruit group did not vary by ethnicity (P=0·38), it did vary for the breads/cereals, milk/milk products and meat/eggs groups (all P<0·001). Adherence to recommendations for the vegetables/fruit group was higher among older women (P=0·001); for the breads/cereals group was higher for women with previous children (P<0·001) and from lower-income households (P<0·001); and for the meat/eggs group was higher for women with previous children (P=0·003) and from lower-income households (P=0·004).

Most pregnant women in New Zealand do not adhere to nutritional guidelines in pregnancy, with only 3 % meeting the recommendations for all four food groups. Adherence varies more so with ethnicity than with other sociodemographic characteristics.

To examine changes in food consumption during pregnancy and the postpartum period in women of major Asian ethnic groups.

Using interviewer-administered questionnaires, we assessed changes in food consumption during pregnancy (26–28 weeks’ gestation) and the postpartum period (3 weeks after delivery) as compared with the usual pre-pregnancy diet.

Singapore.

Pregnant women (n 1027) of Chinese, Malay and Indian ethnicity (mean age 30·4 (sd 5·2) years) who participated in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study.

During pregnancy, participants tended to increase their consumption of milk, fruit and vegetables and decrease their consumption of tea, coffee, soft drinks and seafood (all P < 0·001). Most participants reported adherence to traditional restrictions (‘confinement’) during the early postpartum period (Chinese: 94·8 %, Malay: 91·6 %, Indian: 79·6 %). During the postpartum period, participants tended to increase their consumption of fish and milk-based drinks and decrease their consumption of noodles, seafood, and chocolates and sweets (all P < 0·001). Ethnic differences in food consumption were pronounced during the postpartum period. For example, most Chinese participants (87·2 %) increased their ginger consumption during the postpartum period as compared with smaller percentages of Malays (31·8 %) and Indians (40·8 %; P for ethnic difference <0·001). Similar ethnic differences were observed for cooking wine/alcohol, herbs and spices, and herbal tea consumption.

Marked changes in food consumption that reflect both modern dietary recommendations and the persistence of traditional beliefs were observed in Singaporean women during pregnancy and the postpartum period. Traditional beliefs should be considered in interventions to improve dietary intakes during these periods.

First, to evaluate the ability of a short dietary questionnaire (SDQ) to estimate energy intake (EI) on group and individual levels compared with total energy expenditure (TEE) measured by the doubly labelled water method. Second, to compare the SDQ's performance in estimating energy, nutrient and food intakes with a sixty-six-item FFQ used in large-scale Swedish epidemiological research.

Cross-sectional.

Umeå, Sweden.

In total, sixty-five non-pregnant women, of whom thirty-one were overweight or obese, and twenty-five pregnant, normal-weight women completed the protocol.

On average, the SDQ captured 78 % and 79 % of absolute TEE in the non-pregnant and pregnant normal-weight women, respectively. Furthermore, the SDQ captured an average of 57 % of TEE in the overweight/obese non-pregnant women. The Spearman correlation of EI and TEE was significant in the overweight and obese women only (ρ = 0·37, 95 % CI 0·02, 0·64). There was no significant difference between the SDQ and the more extensive FFQ in the ability to assess EI when compared with TEE. Intakes of most nutrients and foods were significantly higher when assessed with the SDQ compared with the FFQ.

A new short dietary questionnaire with an alternative design underestimated EI of non-pregnant and pregnant, overweight and obese women on a group level but was able to rank the overweight/obese women according to EI. Furthermore, the short questionnaire captured as much or more of the energy, nutrient and food intakes of non-pregnant normal-weight and overweight/obese women on the group level as a traditional, more extensive FFQ.

Fish consumption influences a number of health outcomes. Few studies have directly compared dietary assessment methods to determine the best approach to estimating intakes of fish and its component nutrients, including DHA, and toxicants, including methylmercury. Our objective was to compare three methods of assessing fish intake.

We assessed 30 d fish intake using three approaches: (i) a single question on total fish consumption; (ii) a brief comprehensive FFQ that included four questions about fish; and (iii) a focused FFQ with thirty-six questions about different finfish and shellfish.

Obstetrics practices in Boston, MA, USA.

Fifty-nine pregnant women who consumed ≤2 monthly fish servings.

Estimated intakes of fish, DHA and Hg were lowest with the one-question screener and highest with the thirty-six-item fish questionnaire. Estimated intake of DHA with the thirty-six-item questionnaire was 4·4-fold higher (97 v. 22 mg/d), and intake of Hg was 3·8-fold higher (1·6 v. 0·42 μg/d), compared with the one-question screener. Plasma DHA concentration was correlated with fish intake assessed with the one-question screener (Spearman r = 0·27, P = 0·04), but not with the four-item FFQ (r = 0·08, P = 0·54) or the thirty-six-item fish questionnaire (r = 0·01, P = 0·93). In contrast, blood and hair Hg concentrations were similarly correlated with fish and Hg intakes regardless of the assessment method (r = 0·35 to 0·52).

A longer questionnaire provides no advantage over shorter questionnaires in ranking intakes of fish, DHA and Hg compared with biomarkers, but estimates of absolute intakes can vary by as much as fourfold across methods.

To assess sociodemographic correlates of micronutrient intakes from food and dietary supplements in an urban, ethnically diverse sample of pregnant women in the USA.

Cross-sectional analyses of data collected using a validated semi-quantitative FFQ. Associations between racial, ethnic and sociodemographic factors and micronutrient intakes were examined using logistic regression controlling for pre-pregnancy BMI, maternal age and smoking status.

Prenatal clinics, Boston, MA, USA.

Analyses included pregnant women (n 274) in the PRogramming of Intergenerational Stress Mechanisms (PRISM) study, an urban longitudinal cohort designed to examine how stress influences respiratory health in children when controlling for other environmental exposures (chemical stressors, nutrition).

High frequencies of vitamin E (52 %), Mg (38 %), Fe (57 %) and vitamin D (77 %) inadequacies as well as suboptimal intakes of choline (95 %) and K (99 %) were observed. Factors associated with multiple antioxidant inadequacies included being Hispanic or African American, lower education and self-reported economic-related food insecurity. Hispanics had a higher prevalence of multiple methyl-nutrient inadequacies compared with African Americans; both had suboptimal betaine intakes and higher odds for vitamin B6 and Fe inadequacies compared with Caucasians. Nearly all women (98 %) reported Na intakes above the tolerable upper limit; excessive intakes of Mg (35 %), folate (37 %) and niacin (38 %) were also observed. Women reporting excessive intakes of these nutrients were more likely Caucasian or Hispanic, more highly educated, US-born and did not report food insecurity.

Racial/ethnic and other sociodemographic factors should be considered when tailoring periconceptional dietary interventions for urban ethnic women in the USA.

Iodine is an essential micronutrient needed for the production of thyroid hormones. Pregnant mothers who are deficient in iodine provide less iodine to the fetal thyroid. This results in low production of thyroid hormones by the fetal thyroid, thereby leading to compromised mental and physical development of the fetus. The current study aimed to assess the current status of iodine nutrition among pregnant mothers in Himachal Pradesh, India, a known endemic region for iodine deficiency.

Three districts, namely Kangra, Kullu and Solan, were selected.

In each district, thirty clusters (villages) were identified by utilizing the population-proportional-to-size cluster sampling methodology. In each cluster, seventeen pregnant mothers attending the antenatal clinics were included.

A total of 1711 pregnant mothers (647 from Kangra, 551 from Kullu and 513 from Solan) were studied. Clinical examination of the thyroid of each pregnant mother was conducted. Spot urine samples were collected from ten pregnant mothers in each cluster. Similarly, salt samples were collected from eleven pregnant mothers in each cluster.

Total goitre rate was 42·2 % (Kangra), 42·0 % (Kullu) and 19·9 % (Solan). The median urinary iodine concentration was 200 μg/l (Kangra), 149 μg/l (Kullu) and 130 μg/l (Solan). The percentage of pregnant mothers consuming adequately iodized salt (iodine content of 15 ppm and more) was found to be 68·3 % (Kangra), 60·3 % (Kullu) and 48·5 % (Solan).

Pregnant mothers in Kullu and Solan districts had iodine deficiency as indicated by a median urinary iodine concentration less than 150 μg/l.

To examine the association between complementary feeding indicators and attained linear growth at 6–23 months.

Secondary analysis of Phase V Demographic and Health Surveys data (2003–2008). Country-specific ANOVA models were used to estimate effects of three complementary feeding indicators (minimum meal frequency, minimum dietary diversity and minimum adequate diet) on length-for-age, adjusted for covariates and interactions of interest.

Twenty-one countries (four Asian, twelve African, four from the Americas and one European).

Sample sizes ranging from 608 to 13 676.

Less than half the countries met minimum meal frequency and minimum dietary diversity, and only Peru had a majority of the sample receiving a minimum adequate diet. Minimum dietary diversity was the indicator most consistently associated with attained length, having significant positive effect estimates (ranging from 0·16 to 1·40 for length-for-age Z-score) in twelve out of twenty-one countries. Length-for-age declined with age in all countries, and the greatest declines in its Z-score were seen in countries (Niger, −1·9; Mali, −1·6; Democratic Republic of Congo, −1·4; Ethiopia, −1·3) where dietary diversity was persistently low or increased very little with age.

There is growing recognition that poor complementary feeding contributes to the characteristic negative growth trends observed in developing countries and therefore needs focused attention and its own tailored interventions. Dietary diversity has the potential to improve linear growth. Using four food groups to define minimum dietary diversity appears to capture enough information in a simplified, standard format for multi-country comparisons of the quality of complementary diets.

To examine the micronutrient status of disadvantaged pre-schoolers from Northeast Brazil, following the introduction of pro-poor policies, by assessing the prevalence of anaemia and micronutrient deficiencies and the role of sociodemographic factors, genetic Hb disorders and parasitic infections.

In a cross-sectional study, data on sociodemographic status, health, growth, genetic Hb disorders, parasites and nutrient supply from day-care meals were obtained. Fasting blood samples were collected and analysed for Hb, serum ferritin, transferrin receptor, folate, vitamin B12, retinol, Zn and Se.

Seven philanthropic day-care centres serving urban slums in Salvador, Northeast Brazil.

Pre-schoolers aged 3–6 years from disadvantaged households.

Of the 376 sampled children, 94 % were of black or mixed race; 33 % and 29 % had at least one genetic Hb disorder and intestinal parasite, respectively. Stunting and underweight were ≤5 %; 14 % were overweight. Day-care centres supplied micronutrient-dense meals and snacks each weekday. Less than 10 % of pre-schoolers had anaemia and micronutrient deficiencies. Predictors (P < 0·05) of Hb were α3·7 thalassaemia, Se and retinol (but not ferritin). Micronutrient predictors (P < 0·05) were: elevated α1-glycoprotein for ferritin, Hb AS and BMI Z-score >1 for transferrin receptor, Zn and elevated α1-glycoprotein for retinol, sex and helminths for Se, helminths for vitamin B12, and Giardia intestinalis infection for serum folate.

Impaired growth, anaemia and micronutrient deficiencies were uncommon among these disadvantaged pre-schoolers attending day care. A range of interventions including provision of micronutrient-dense, fortified day-care meals, deworming and vitamin A supplementation likely contributed to improved micronutrient status, suggesting expanded coverage of these programmes.

The increasing prevalence of childhood overweight is an important health issue. There is a need for longitudinal research among children in order to identify risk factors for childhood overweight. The objective of the present research was to identify potential sociodemographic and behavioural risk factors for development of childhood overweight among 3- to 6-year-old children.

Longitudinal study.

Sixteen pre-primary and primary schools.

BMI Z-scores at baseline and two follow-up measurements were calculated for 568 children. Sociodemographic, parental adiposity, familial composition, child's diet, physical activity and sedentary behavioural data were collected through questionnaires.

Several risk factors for the development of childhood overweight were found. Being an only child, lower maternal educational level, maternal and paternal overweight, more than 1 h screen time on weekdays and high soft drinks consumption were shown to be positively associated with the development of childhood overweight.

Although behavioural factors are important, our findings support the thesis that interventions on the prevention of childhood overweight should focus on high-risk groups, i.e. children from low socio-economic background or with high parental BMI. Interventions should address the whole family and take into account their lifestyle and structure.

To assess adherence to the Mediterranean diet and nutrient intakes in a population of Sicily, southern Italy and to evaluate possible determinants, particularly socio-cultural and lifestyle factors.

Cross-sectional.

Urban and rural areas of eastern Sicily.

Between May 2009 and December 2010, 3090 adults were randomly recruited through the collaboration of fourteen general practitioners. Adherence to the Mediterranean diet was measured by the MedDietScore. Nutrient intakes were assessed through the 24 h recall of the previous day's dietary intake.

Rural participants were barely more adherent to the Mediterranean diet than their urban counterparts (mean scores were 27·8 and 27·2, respectively, P = 0·037). The MedDietScore was correlated with intakes of MUFA, fibre and vitamin C, as well as with consumption of non-refined cereals, vegetables, fruit, meat, dairy products, alcohol and nuts. Regression analysis revealed that older and more educated people were more likely to be in the highest tertile of MedDietScore (OR = 1.90; 95 % CI 1·39, 2·59 and OR = 1·29; 95 % CI 1·05, 1·58, respectively). A significant difference in quantity (moderate) and quality (red wine and beer) of alcohol was found according to adherence to the Mediterranean diet. Finally, more active participants were 1·5 times more likely to form part of the high-adherence group.

A slow but concrete moving away from traditional patterns has been observed in younger people and low educated people. Public health interventions should focus on these target populations in order to improve the quality of their diet.

Malnutrition is one of the most important health problems, especially in developing countries. The present study aimed to describe the socio-economic inequality in stunting and its determinants in Iran for the first time.

Cross-sectional, population-based survey, carried out in 2009. Using randomized cluster sampling, weight and height of children were measured and anthropometric indices were calculated based on child growth standards given by the WHO. Socio-economic status of families was determined using principal component analysis on household assets and social specifications of families. The concentration index was used to calculate socio-economic inequality in stunting and its determinants were measured by decomposition of this index. Factors affecting the gap between socio-economic groups were recognized by using the Oaxaca–Blinder decomposition method.

Shahroud District in north-eastern Iran.

Children (n 1395) aged <6 years.

The concentration index for socio-economic inequality in stunting was −0·1913. Mother's education contributed 70 % in decomposition of this index. Mean height-for-age Z-score was −0·544 and −0·335 for low and high socio-economic groups, respectively. Mother's education was the factor contributing most to the gap between these two groups.

There was a significant socio-economic inequality in the studied children. If mother's education is distributed equally in all the different groups of Iranian society, one can expect to eliminate 70 % of the socio-economic inequalities. Even in high socio-economic groups, the mean height-for-age Z-score was lower than the international standards. These issues emphasize the necessity of applying new interventions especially for the improvement of maternal education.

To provide nationally representative data on the prevalence of anaemia, vitamin A and Fe deficiencies among pre-school age children (pre-SAC) and non-pregnant women of reproductive age (WRA), and on vitamin B12 and folate deficiencies in WRA, and the influence of inflammation on their interpretation.

A cross-sectional survey to measure anthropometry, malaria parasitaemia and micronutrient status. Specifically, blood samples were analysed for Hb, plasma ferritin, soluble transferrin receptors, C-reactive protein, α1-acid glycoprotein, retinol-binding protein, vitamin B12 and folate.

Côte d'Ivoire in 2007.

Nine hundred and twenty-eight WRA and 879 pre-SAC.

In WRA, prevalence of Plasmodium parasitaemia (5 %) was low, but inflammation (34 %) was higher. Anaemia was a severe public health problem and prevalence differed by residency and eco-region. Inflammation-adjusted Fe deficiency was highest in urban areas (20 %). Nationally, folate deficiency was 86 %, higher in urban areas and varied by eco-region. Prevalence of vitamin B12 deficiency was low but higher in the rural areas and the north. Inflammation-adjusted vitamin A deficiency was very low (1 %). In pre-SAC, prevalence of inflammation (67 %) and Plasmodium parasites (25 %) was high; the latter was associated with poverty, rural residency and higher ferritin concentrations. Anaemia was classified as a severe public health problem (72 %), and was higher in rural areas (76 %) and the north (87 %). A quarter of pre-SAC suffered from vitamin A deficiency (inflammation-adjusted) and prevalence of undernutrition was high.

Prevalence of inflammation, Plasmodium parasitaemia and micronutrient deficiencies were high in Côte d'Ivoire, particularly in pre-SAC. Nutritional interventions should be accompanied by strategies to reduce exposure to infections.

To investigate the association between eating behaviours (eating speed and energy intake of main meals) and overweight in pre-school children.

Cross-sectional study. Data consisted of measurements (height and weight), questionnaire information (eating behaviours of eating speed and overeating) and on-site observation data (meal duration and energy intake of main meals).

Seven kindergartens in Beijing, China.

Pre-school children (n 1138; age range 3·1–6·7 years old) from seven kindergartens participated in the study.

The multivariate-adjusted odds ratio of overweight in participants with parent-reported ‘more than needed food intake’ was 3·02 (95 % CI 2·06, 4·44) compared with the ‘medium food intake’ participants, and higher eating speed was associated with childhood overweight. For the two observed eating behaviours, each 418·7 kJ (100 kcal) increase of lunch energy intake significantly increased the likelihood for overweight by a factor of 1·445, and each 5-min increase in meal duration significantly decreased the likelihood for overweight by a factor of 0·861. Increased portions of rice and cooked dishes were significantly associated with overweight status (OR = 2·274; 95 % CI 1·360, 3·804 and OR = 1·378; 95 % CI 1·010, 1·881, respectively).

Eating speed and excess energy intake of main meals are associated with overweight in pre-school children.

To examine differences in overweight and obesity of second-generation Turkish, Moroccan and Surinamese migrants v. first-generation migrants and the ethnic Dutch. We also studied the influence of sociodemographic factors on this association.

Data were collected in 2008 in a cross-sectional postal and online health survey.

Four major Dutch cities.

In the survey 42 686 residents aged 16 years and over participated. Data from Dutch (n 3615) and second/first-generation Surinamese (n 230/139), Turkish (n 203/241) and Moroccan (n 172/187) participants aged 16–34 years were analysed using logistic regression with overweight (BMI ≥ 25·0 kg/m2) and obesity (BMI ≥ 30·0 kg/m2) as dependent variables. BMI was calculated from self-reported body height and weight. Sociodemographic variables included sex, age, marital status, educational level, employment status and financial situation.

After controlling for age, overweight (including obesity) was more prevalent in most second-generation migrant subgroups compared with the Dutch population, except for Moroccan men. Obesity rates among second-generation migrant men were similar to those among the Dutch. Second-generation migrant women were more often obese than Dutch women. Ethnic differences were partly explained by the lower educational level of second-generation migrants. Differences in overweight between second- and first-generation migrants were only found among Moroccan and Surinamese men.

We did not find a converging trend for the overweight and obesity prevalence from second-generation migrants towards the Dutch host population. Therefore, preventive interventions should also focus on second-generation migrants to stop the obesity epidemic.

The present study was designed to assess physical activity, sedentary behaviours and dietary habits among adolescents in Kuwait and to compare the differences between genders.

A cross-sectional study was conducted among secondary-school children who participated in the Arab Teens Lifestyle Study (ATLS), a multi-centre collaborative project.

Secondary schools in Kuwait.

Adolescents (463 boys and 443 girls), aged 14–19 years.

Nearly half (44·6 %) of the boys and three-quarters (76·0 %) of the girls did not meet the recommended daily physical activity levels (≥2520 MET-min/week, moderate to vigorous intensity). Nearly all (96·3 % of boys and 96·7 % of girls) adolescents reported spending >2 h/d on screen time, with girls found to spend more time per day watching television (P = 0·02) and using a computer (P < 0·001). The large majority of the adolescents reported skipping breakfast and not having milk and milk products, vegetables and fruit daily, while nearly two-thirds of the boys and girls had sugar-sweetened drinks on more than 3 d/week. Compared with girls, boys reported consuming more fruit (3·4 v. 2·8 times/week, P = 0·001), dairy products (4·5 v. 3·6 times/week, P = 0·001) and energy drinks (1·3 v. 1·1 times/week, P = 0·003).

The majority of the Kuwaiti adolescents, especially girls, do not perform adequate physical activity, spend more time on sedentary activities and have unhealthy dietary practices. The findings emphasize an urgent need for implementing an appropriate intervention for promoting physical activity, healthy eating and reducing sedentary behaviours among these children.

To describe the contribution of mixed dishes to vegetable consumption and to estimate vegetable intake according to specific types of vegetables and other foods among US children and adolescents.

The 2003–2008 National Health and Nutrition Examination Survey (NHANES), a nationally representative probability survey conducted in the USA.

Civilian non-institutionalized US population.

All children and adolescents aged 2–18 years who met eligibility criteria (n 9169).

Approximately 59 % of total vegetable intake came from whole forms of vegetables with 41 % coming from a mixed dish. White potatoes (10·7 (se 0·6) %), fried potatoes (10·2 (se 0·4) %), potato chips (8·6 (se 0·5) %) and other vegetables (9·2 (se 0·5) %) accounted for most vegetables in their whole forms, whereas pasta dishes (9·5 (se 0·4) %), chilli/soups/stews (7·0 (se 0·5) %), pizza/calzones (7·6 (se 0·3) %) and other foods (13·7 (se 0·6) %) accounted for most mixed dishes. Usual mean vegetable intake was 1·02 cup equivalents/d; however, after excluding vegetables from mixed dishes, mean intake fell to 0·54 cup equivalents/d and to 0·32 cup equivalents/d when fried potatoes were further excluded.

Mixed dishes account for nearly half of overall vegetable intake in US children and adolescents. It is critical for future research to examine various components of vegetable intake carefully in order to inform policy and programmatic efforts aimed at improving dietary intake among children and adolescents.

To examine the extent to which the gendered division of labour persists within households in the USA in regard to meal planning/preparation and food shopping activities.

Secondary analysis of cross-sectional data.

2007–2008 US National Health and Nutrition Examination Survey.

Sub-sample of 3195 adults at least 20 years old who had a spouse or partner.

Analyses revealed that the majority of women and men reported they shared in both meal planning/preparing and food shopping activities (meal planning/preparation: women 54 % and men 56 %; food shopping: women 60 % and men 57 %). Results from multinomial logistic regression analyses indicated that, compared with men, women were more likely to take primary responsibility than to share this responsibility and less likely to report having no responsibility for these tasks. Gender differences were observed for age/cohort, education and household size.

This study may have implications for public health nutritional initiatives and the well-being of families in the USA.

To examine the association between calculated maternal dietary exposure to Hg in pregnancy and infant birth weight in the Norwegian Mother and Child Cohort Study (MoBa).

Exposure was calculated with use of a constructed database of Hg in food items and reported dietary intake during pregnancy. Multivariable regression models were used to explore the association between maternal Hg exposure and infant birth weight, and to model associations with small-for-gestational-age offspring.

The study is based on data from MoBa.

The study sample consisted of 62 941 women who answered a validated FFQ which covered the habitual diet during the first five months of pregnancy.

Median exposure to Hg was 0·15 μg/kg body weight per week and the contribution from seafood intake was 88 % of total Hg exposure. Women in the highest quintile compared with the lowest quintile of Hg exposure delivered offspring with 34 g lower birth weight (95 % CI −46 g, −22 g) and had an increased risk of giving birth to small-for-gestational-age offspring, adjusted OR = 1·19 (95 % CI 1·08, 1·30). Although seafood intake was positively associated with increased birth weight, stratified analyses showed negative associations between Hg exposure and birth weight within strata of seafood intake.

Although seafood intake in pregnancy is positively associated with birth weight, Hg exposure is negatively associated with birth weight. Seafood consumption during pregnancy should not be avoided, but clarification is needed to identify at what level of Hg exposure this risk might exceed the benefits of seafood.