Reduced risks of neural tube defects and orofacial clefts with higher diet quality

Dietary quality among men and women in 187 countries in 1990 and 2010: a systematic assessment

BACKGROUND

Healthy dietary patterns are a global priority to reduce non-communicable diseases. Yet neither worldwide patterns of diets nor their trends with time are well established. We aimed to characterise global changes (or trends) in dietary patterns nationally and regionally and to assess heterogeneity by age, sex, national income, and type of dietary pattern.

METHODS

In this systematic assessment, we evaluated global consumption of key dietary items (foods and nutrients) by region, nation, age, and sex in 1990 and 2010. Consumption data were evaluated from 325 surveys (71·7% nationally representative) covering 88·7% of the global adult population. Two types of dietary pattern were assessed: one reflecting greater consumption of ten healthy dietary items and the other based on lesser consumption of seven unhealthy dietary items. The mean intakes of each dietary factor were divided into quintiles, and each quintile was assigned an ordinal score, with higher scores being equivalent to healthier diets (range 0-100). The dietary patterns were assessed by hierarchical linear regression including country, age, sex, national income, and time as exploratory variables.

FINDINGS

From 1990 to 2010, diets based on healthy items improved globally (by 2·2 points, 95% uncertainty interval (UI) 0·9 to 3·5), whereas diets based on unhealthy items worsened (-2·5, -3·3 to -1·7). In 2010, the global mean scores were 44·0 (SD 10·5) for the healthy pattern and 52·1 (18·6) for the unhealthy pattern, with weak intercorrelation (r=-0·08) between countries. On average, better diets were seen in older adults compared with younger adults, and in women compared with men (p<0·0001 each). Compared with low-income nations, high-income nations had better diets based on healthy items (+2·5 points, 95% UI 0·3 to 4·1), but substantially poorer diets based on unhealthy items (-33·0, -37·8 to -28·3). Diets and their trends were very heterogeneous across the world regions. For example, both types of dietary patterns improved in high-income countries, but worsened in some low-income countries in Africa and Asia. Middle-income countries showed the largest improvement in dietary patterns based on healthy items, but the largest deterioration in dietary patterns based on unhealthy items.

INTERPRETATION

Consumption of healthy items improved, while consumption of unhealthy items worsened across the world, with heterogeneity across regions and countries. These global data provide the best estimates to date of nutrition transitions across the world and inform policies and priorities for reducing the health and economic burdens of poor diet quality.

FUNDING

The Bill & Melinda Gates Foundation and Medical Research Council.

Possible Further Evidence of Low Genetic Diversity in the El Sidrón (Asturias, Spain) Neandertal Group: Congenital Clefts of the Atlas

We present here the first cases in Neandertals of congenital clefts of the arch of the atlas. Two atlases from El Sidrón, northern Spain, present respectively a defect of the posterior (frequency in extant modern human populations ranging from 0.73% to 3.84%), and anterior (frequency in extant modern human populations ranging from 0.087% to 0.1%) arch, a condition in most cases not associated with any clinical manifestation. The fact that two out of three observable atlases present a low frequency congenital condition, together with previously reported evidence of retained deciduous mandibular canine in two out of ten dentitions from El Sidrón, supports the previous observation based on genetic evidence that these Neandertals constituted a group with close genetic relations. Some have proposed for humans and other species that the presence of skeletal congenital conditions, although without clinical significance, could be used as a signal of endogamy or inbreeding. In the present case this interpretation would fit the general scenario of high incidence of rare conditions among Pleistocene humans and the specific scenariothat emerges from Neandertal paleogenetics, which points to long-term small and decreasing population size with reduced and isolated groups. Adverse environmental factors affecting early pregnancies would constitute an alternative, non-exclusive, explanation for a high incidence of congenital conditions. Further support or rejection of these interpretations will come from new genetic and skeletal evidence from Neandertal remains.

Preventing birth defects: The value of the NBDPS case-control approach

Birth Defect Registries provide a basis for epidemiological research into risk factors, thus facilitating a growing understanding of what causes congenital anomalies and how one might target preventive public health actions and reduce inequalities. The National Birth Defects Prevention Study (NBDPS) has used 10 U.S. registries as a basis for a large case-control study. This commentary reviews its methodology and selected areas of output. The strengths of NBDPS lie in the quality of diagnostic coding and classification of birth defects and its size. The sources of bias in NBDPS data relate particularly to retrospective exposure ascertainment entailing a long period of recall, incomplete ascertainment of terminations of pregnancy for fetal anomaly, and unknown bias in case selection. NBDPS results have shown the protective effect of healthy dietary patterns, but have not been as informative as expected in relation to furthering understanding of the protective effect of folic acid. NBDPS medication studies are making important contributions to addressing the gap in existing evidence systematically across a wide range of birth defects, but are challenged by the quality of information on exposure, dose and underlying disease condition, and the interpretation of results of multiple testing. Studies of environmental contaminants in collaboration with experts in exposure assessment have linked addresses to residential exposure measures, using the advantages of information on residential history and confounders, but are challenged by the need to consider exposure mixtures. NBDPS could increase its public health impact by placing more emphasis on socioeconomic inequalities.

Detecting gene-environment interactions in human birth defects: Study designs and statistical methods

BACKGROUND

The National Birth Defects Prevention Study (NBDPS) contains a wealth of information on affected and unaffected family triads, and thus provides numerous opportunities to study gene-environment interactions (G×E) in the etiology of birth defect outcomes. Depending on the research objective, several analytic options exist to estimate G×E effects that use varying combinations of individuals drawn from available triads.

METHODS

In this study, we discuss important considerations in the collection of genetic data and environmental exposures.

RESULTS

We will also present several population- and family-based approaches that can be applied to data from the NBDPS including case-control, case-only, family-based trio, and maternal versus fetal effects. For each, we describe the data requirements, applicable statistical methods, advantages, and disadvantages.

CONCLUSION

A range of approaches can be used to evaluate potentially important G×E effects in the NBDPS. Investigators should be aware of the limitations inherent to each approach when choosing a study design and interpreting results.

Spina bifida

Spina bifida is a birth defect in which the vertebral column is open, often with spinal cord involvement. The most clinically significant subtype is myelomeningocele (open spina bifida), which is a condition characterized by failure of the lumbosacral spinal neural tube to close during embryonic development. The exposed neural tissue degenerates in utero, resulting in neurological deficit that varies with the level of the lesion. Occurring in approximately 1 per 1,000 births worldwide, myelomeningocele is one of the most common congenital malformations, but its cause is largely unknown. The genetic component is estimated at 60-70%, but few causative genes have been identified to date, despite much information from mouse models. Non-genetic maternal risk factors include reduced folate intake, anticonvulsant therapy, diabetes mellitus and obesity. Primary prevention by periconceptional supplementation with folic acid has been demonstrated in clinical trials, leading to food fortification programmes in many countries. Prenatal diagnosis is achieved by ultrasonography, enabling women to seek termination of pregnancy. Individuals who survive to birth have their lesions closed surgically, with subsequent management of associated defects, including the Chiari II brain malformation, hydrocephalus, and urological and orthopaedic sequelae. Fetal surgical repair of myelomeningocele has been associated with improved early neurological outcome compared with postnatal operation. Myelomeningocele affects quality of life during childhood, adolescence and adulthood, posing a challenge for individuals, families and society as a whole. For an illustrated summary of this Primer, visit: http://go.nature.com/fK9XNa.

Better diet quality before pregnancy is associated with reduced risk of gastroschisis in Hispanic women

BACKGROUND

Gastroschisis is unique because of its substantial risk in pregnancies of adolescent women. Adolescents may have poor diet quality, which places them at higher risk of gastroschisis.

OBJECTIVE

We investigated whether better maternal diet quality, measured by 2 different indices, reduced the risk of gastroschisis.

METHODS

We used case-control data from the National Birth Defects Prevention Study to investigate maternal diet quality among 1125 gastroschisis cases and 9483 controls (estimated delivery dates between 1997 and 2009). Cases were ascertained from 10 U.S. birth defect surveillance systems. Control subjects were randomly selected from birth certificates or hospital records. Using a 58-item food-frequency questionnaire, interviewers queried mothers about their average food and cereal intake during the year before conception. Diet quality scores [Diet Quality Index (DQI) and Mediterranean diet score (MDS)] were calculated using specific components. Women were excluded if they consumed <500 or >5000 kcal/d, reported pregestational diabetes, or had >1 missing food item. Quartile-specific adjusted ORs (aORs) were calculated, using as reference the lowest quartile.

RESULTS

Overall, we observed a statistically significant decrease with increasing diet quality for both the DQI and MDS. When stratified by maternal race/ethnicity, this finding was confined to Hispanic women. Among Hispanic women, the risk of gastroschisis decreased significantly with increasing DQI quartiles: quartile 2, aOR = 0.58 (95% CI: 0.40, 0.86); quartile 3, aOR = 0.52 (95% CI: 0.36, 0.79); and quartile 4, aOR = 0.48 (95% CI: 0.32, 0.76). Increasing diet quality, as measured by the MDS, showed reduced risk of gastroschisis among women, mostly Hispanic, who were born outside the United States: quartile 2, aOR = 0.62 (95% CI: 0.33, 1.16); quartile 3, aOR = 0.51 (95% CI: 0.28, 0.94); and quartile 4, aOR = 0.50 (95% CI: 0.28, 0.90).

CONCLUSIONS

Increasing diet quality was associated with a reduced risk of gastroschisis only among Hispanic and foreign-born women, but these findings require replication.

Factors associated with a low adherence to a Mediterranean diet pattern in healthy Spanish women before pregnancy

OBJECTIVE

To analyse the factors associated with the level of adherence to a Mediterranean dietary pattern in healthy Spanish women before pregnancy.

DESIGN

A prospective series of 1175 women. An FFQ validated in Spanish populations served to collect dietary data. The Mediterranean Diet Adherence Index was used to assess the level of adherence to a Mediterranean diet pattern. Polytomic regression was performed to identify the associated factors.

SETTING

Catchment area of Virgen de las Nieves University Hospital, Andalusia, Spain.

SUBJECTS

The women were invited to participate in the study at the 20th-22nd gestational week. The selection criteria were: Spanish nationality, 18 years of age or older, singleton pregnancy and absence of health problems that required modifying the diet or physical activity.

RESULTS

An inverse relationship was found between women's age and level of adherence to a Mediterranean diet pattern, with a clear dose-response association: a younger age entailed worse adherence (P < 0·001). The habit of smoking and sedentary lifestyle had a positive relationship with low adherence, giving OR = 5·36 (95 % 1·91, 15·07) for women who smoked >20 cigarettes/d and OR = 2·07 (95 % CI 1·34, 3·17) for sedentary women. Higher age, higher educational level, and higher social class of the women were associated with a higher level of adherence to the Mediterranean diet (P < 0·001).

CONCLUSIONS

In our sample population, younger age, lower social class, primary educational level and elements of an unhealthy lifestyle such as smoking and lack of exercise were associated with low adherence to a Mediterranean diet.

Association of sociodemographic and nutritional factors with risk of neural tube defects in the North Indian population: a case-control study

OBJECTIVE

To assess the role of sociodemographic and nutritional factors in the incidence of births affected by neural tube defects (NTD) in the North Indian population.

DESIGN

Case-control study.

SETTING

Government hospitals of Delhi, India.

SUBJECTS

Subjects comprised 284 mothers of NTD children (cases) and 568 mothers of healthy children (controls).

RESULTS

Significant differences were found between case and control mothers with respect to maternal age (P = 0·005), type of drinking water (P = 0·03) and consumption of milk (P = 0·01). Univariate and multivariate analysis suggested an association of unpasteurized milk use, low consumption of vegetables, low consumption of fruits and vegetarian dietary habits with NTD births. Further, variation in the risk factors for upper and lower NTD types was also observed, pointing towards phenotypic heterogeneity in the aetiology.

CONCLUSIONS

The results of the present study suggest an increased risk of NTD infants in mothers with low consumption of vegetables, fruits and milk and having vegetarian dietary habits. So, in order to reduce these devastating birth defects in future offspring, better nutritional care should be provided to mothers by suggesting dietary modifications and augmenting additional micronutrient supplementation during the periconceptional period.

Periconceptional nutrient intakes and risks of orofacial clefts in California

BACKGROUND

Evidence indicates that maternal nutrient intake may play a role in the development of birth defects. We investigated the association of maternal periconceptional intake of vitamin supplements and dietary nutrients with risk of developing cleft palate (CP) and cleft lip with or without cleft palate (CLP).

METHODS

Data were from a population-based, case-control study of fetuses and liveborn infants delivered in California in 1999-2003. Analyses included 170 cases with CP, 425 with CLP, and 534 nonmalformed controls. Dietary intake was estimated from a food frequency questionnaire.

RESULTS

Vitamin supplement intake was associated with a modestly decreased risk of clefts, but the confidence intervals (CIs) include 1.0. Among women who did not use vitamin supplements, dietary intake of several micronutrients was associated with risk of clefts. We found at least a twofold elevated risk of CP with low intake of riboflavin, magnesium, calcium, vitamin B12, and zinc; all CIs excluded 1.0. For CLP, we found at least a twofold elevated risk with low intake of niacin, riboflavin, vitamin B12, and calcium, and a decreased risk with high intake of folate and cryptoxanthin; all CIs excluded 1.0.

CONCLUSION

The results suggest that periconceptional nutrient intake may be associated with risk of CP and CLP.

Maternal dietary nutrient intake and risk of preterm delivery

OBJECTIVE

To examine maternal dietary intake and preterm delivery.

STUDY DESIGN

Data included 5738 deliveries from the National Birth Defects Prevention Study. Odds ratios (ORs) reflected risks of delivery at <32, 32-34, or 35-36 versus ≥ 37 weeks for maternal intake in the lowest or highest quartile of nutrient intake compared with the middle two.

RESULTS

Among deliveries < 32 weeks, many ORs were ≥ 1.5 or ≤ 0.7, but few confidence intervals excluded one. ORs were ≥ 1.5 for lowest quartiles of protein, thiamin, riboflavin, choline, vitamin A, α-carotene, β-carotene, vitamin E, iron, copper, and zinc and for highest quartiles of carbohydrate, glycemic index, and Mediterranean Diet Score. ORs were ≤ 0.7 for lowest quartiles of glycemic index and betaine and for highest quartiles of protein, alanine, methionine, vitamin B6, betaine, and calcium. Few ORs met these criteria for later preterm deliveries.

CONCLUSIONS

Results suggested an association of nutrient intake with earlier preterm deliveries.

Maternal dietary patterns are associated with risk of neural tube and congenital heart defects

Studying empirically derived dietary patterns is useful in understanding dietary practice. We classified women by their dietary patterns using latent class analysis of 66 foods and studied the association of these patterns with neural tube defects (NTDs) and congenital heart defects (CHDs) in the U.S. National Birth Defects Prevention Study (1997-2005). Logistic regression models used data from 1,047 with an NTD, 6,641 with a CHD, and 6,123 controls that were adjusted for maternal characteristics and tested the effect modification of multivitamin supplement use. Four latent dietary patterns were identified: prudent, Western, low-calorie Western, and Mexican. Among participants who did not use supplements, those in the Mexican, Western, and low-calorie Western classes were significantly more likely (odds ratios of 1.6, 1.5, and 1.4, respectively) to have offspring born with NTDs than were those in the prudent class after adjustment of for dietary folic acid intake. In contrast, among supplement users, there was no difference in the incidence of NTDs between classes. Associations between dietary class and CHD subgroups were not modified by supplement use except for tetralogy of Fallot; among supplement users, those in the Western class were twice as likely (95% confidence interval: 1.4, 2.8) as the prudent class to have offspring with tetralogy of Fallot. Women who adhered to a Western diet were 1.2 (95% confidence interval: 1.03, 1.35) times more likely to have an infant with septal heart defect than were women who adhered to a prudent diet. A prudent dietary pattern, even with folate fortification, may decrease the risk of NTDs and some heart defects.

Modeling the potential public health impact of prepregnancy obesity on adverse fetal and infant outcomes

OBJECTIVE

Approximately one-third of US reproductive-aged women are obese, and prepregnancy obesity is a strong risk factor for adverse fetal and infant outcomes. The annual number of preventable adverse fetal and infant outcomes associated with prepregnancy obesity in the U.S. was estimated.

DESIGN AND METHODS

Adverse fetal and infant outcomes for which statistically significant associations with prepregnancy obesity had been reported by peer-reviewed meta-analyses, which included fetal deaths and nine different major birth defects, were assessed. The true prevalence of prepregnancy obesity was estimated by multiplying self-reported prepregnancy obesity by a bias factor based on the difference between measured and self-reported obesity in U.S. adult women. A Monte Carlo simulation approach was used to model the attributable fraction and preventable number, accounting for uncertainty in the estimates for: strength of the association with obesity, obesity prevalence, and outcome prevalence.

RESULTS

Eliminating the impact of prepregnancy obesity would potentially prevent the highest numbers of four outcomes: fetal deaths (6,990; uncertainty interval [UI] 4,110-10,080), congenital heart defects (2,850; UI 1,035-5,065), hydrocephalus (490; UI 150-850), and spina bifida (405; UI 305-505). If 10% of women with prepregnancy obesity achieved a healthy weight before pregnancy or otherwise mitigated the impact of obesity, nearly 300 congenital heart defects and 700 fetal deaths per year could potentially be prevented.

CONCLUSION

This simulation suggests that effective prevention strategies to reduce prepregnancy obesity or the risk associated with obesity could have a measurable impact on infant health in the US.

Maternal dietary patterns during pregnancy and child internalising and externalising problems. The Generation R Study

BACKGROUND & AIMS

Maternal nutritional factors during pregnancy have been linked to foetal brain development and subsequent offspring behaviour. Less is known about associations between maternal dietary patterns and offspring behaviour.

METHODS

Within a population-based cohort, we assessed maternal diet using a food frequency questionnaire. Three dietary patterns were derived by means of Principal Component Analysis. Child internalising (emotionally reactive, anxious/depressed or withdrawn, having somatic complaints) and externalising problems (inattention, aggression) were assessed with the Child Behaviour Checklist at 1.5, 3 and 6 years in 3104 children. We assessed the association of maternal Mediterranean, Traditionally Dutch and Confectionary dietary pattern during pregnancy with child internalising and externalising problems.

RESULTS

After adjustment, the Mediterranean diet was negatively associated (ORper SD in Mediterranean score = 0.90, 95% CI: 0.83-0.97) and the Traditionally Dutch diet was positively associated with child externalising problems (ORper SD in Traditionally Dutch score = 1.11, 95% CI: 1.03-1.21). Neither diet was associated with internalising problems.

CONCLUSIONS

Both low adherence to the Mediterranean diet and high adherence to the Traditionally Dutch diet during pregnancy are associated with an increased risk of child externalising problems. Further research is needed to unravel the effects of nutrient interplay during and after pregnancy on child behavioural development.

Nutritional factors and hypospadias risks

BACKGROUND

We examined whether hypospadias was associated with several aspects of the diet, including intake of animal products, intake of several nutrients and food groups related to a vegetarian diet and oestrogen metabolism, and diet quality.

METHODS

The study included deliveries from 1997 to 2005 that were part of the National Birth Defects Prevention Study. Diet was assessed by food frequency questionnaire during maternal telephone interviews, and two diet quality indices were developed based on existing indices. Analyses included 1250 cases with second- or third-degree hypospadias (urethra opened at the penile shaft, scrotum or perineum) and 3118 male, liveborn, non-malformed controls. All odds ratios (OR) and 95% confidence intervals [CI] were estimated from logistic regression models that included several potential confounders, including energy intake.

RESULTS

Intake of animal products was not associated with hypospadias; for example, the adjusted OR for any vs. no intake of meat was 1.0 [95% CI 0.6, 1.6]. Frequency of intake of meat or other animal products was also not associated with hypospadias, nor was intake of iron or several nutrients that are potentially related to oestrogen metabolism. Diet quality was also not associated with hypospadias; the OR for diet quality in the highest vs. lowest quartile for the two diet quality indices were 1.0 [95% CI 0.6, 1.6] and 0.9 [95% CI 0.7, 1.1].

CONCLUSION

This large study does not support an association of a vegetarian diet or worse diet quality with hypospadias.

Diabetes-induced birth defects: what do we know? What can we do?

Birth defects are the leading cause of infant mortality in the United States, which has one of the highest infant mortality rates in the developed world. Many of these birth defects can be attributed to pre-existing, or pregestational, diabetes in pregnancy, which significantly increases a mother's risk of having a child with a major birth defect. Strict preconceptional and early pregnancy glucose control, supplementation with multivitamins and fatty acids, and lower glycemic dietary management have been shown to reduce the incidence of birth defects in experimental and epidemiologic studies. However, because more than half of pregnancies are unplanned, these methods are not generalizable across the population. Thus, better interventions are urgently needed. Based on what we know about the molecular pathophysiology of diabetic embryopathy, our laboratory and others are developing interventions against to key molecular targets in this multifactorial disease process.