Nutritional supplementation during pregnancy and offspring cardiovascular disease risk in The Gambia

Effects of maternal calcium supplementation on offspring blood pressure and growth in childhood and adolescence in a population with a low-calcium intake: follow-up study of a randomized controlled trial

BACKGROUND

The World Health Organization recommends calcium supplementation (1500-2000 mg/d) during pregnancy for women with a low-calcium intake.

OBJECTIVES

The purpose of this study was to investigate whether pregnancy calcium supplementation affects offspring blood pressure and growth in The Gambia where calcium intakes are low (300-400 mg/d).

METHODS

Follow-up of offspring born during a randomized controlled trial of pregnancy calcium supplementation (ISRCTN96502494, 1996-2000) in which mothers were randomly assigned to 1500 mg Ca/d (Ca) or placebo (P) from 20 wk pregnancy to delivery. Offspring were enrolled at age 3 y in studies where blood pressure and anthropometry were measured under standardized conditions at approximately 2-yearly intervals. Mean blood pressure and growth curves were fitted for females and males separately, using the longitudinal SuperImposition by Translation and Rotation (SITAR) mixed effects model. This generates 3 individual-specific random effects: size, timing, and intensity, reflecting differences in size, age at peak velocity, and peak velocity through puberty relative to the mean curve, respectively.

RESULTS

Five hundred twenty-three singleton infants were born during the trial (maternal group assignment: Ca/P = 259/264). Four hundred ninety-one were enrolled as children (females: F-Ca/F-P = 122/129 and males: M-Ca/M-P = 119/121) and measured regularly from 3.0 y to mean age 18.4 y; 90% were measured on ≥8 occasions. SITAR revealed differences in the systolic blood pressure and height curves between pregnancy supplement groups in females, but not in males. F-Ca had lower systolic blood pressure than F-P at all ages (size = -2.1 ± SE 0.8 mmHg; P = 0.005) and lower peak height velocity (intensity = -2.9 ± SE 1.1%, P = 0.009). No significant pregnancy supplement effects were seen for other measures.

CONCLUSIONS

This study showed, in female offspring, that pregnancy calcium supplementation may lower systolic blood pressure and slow linear growth in childhood and adolescence, adding to evidence of offspring sexual dimorphism in responses to maternal supplementation. Further research is warranted on the long-term and intergenerational effects of antenatal supplementations. This trial was registered at ISRCTN Registry as ISRCTN96502494.

Hypertension among adolescents in sub-Saharan Africa: a systematic review

Introduction

Hypertension (HTN) among adolescents is common in high-income countries, and leads to increased premature cardiovascular diseases (CVD). In sub-Saharan Africa (SSA), the prevalence of HTN among adolescents, associated risk factors and CVD complications are not well-described. Such data is needed for planning public health programs to prevent premature CVD in SSA.

Methods

We systematically searched 5 databases (MEDLINE, Embase, Google Scholar, Web of Science, and African Index Medicus) from their establishment to December 2021. Key search terms were: adolescent, arterial hypertension, and names of the 48 countries in SSA. We used Covidence® to manage the search results. The review was registered in the Open Science Framework (OSF) https://osf.io/p5sbt/.

Results

We identified 4,008 articles out of which we screened 3,088 abstracts, and reviewed 583 full-text articles. We finally included 92 articles that were published between 1968 to December 2021. The majority were cross-sectional studies (80%) and conducted in school settings (78%). The risk of bias was low for 59 studies (64.1%), moderate for 29 studies (31.5%), and high for 4 studies (4.3%). Overall, the prevalence of HTN varied widely from 0.18% to 34.0% with a median (IQR) of 5.5% (3.1%, 11.1%). It was relatively higher in studies using automated blood pressure (BP) devices, and in studies defining HTN using thresholds based on percentile BP distribution for one's height, age, and sex. In addition, the prevalence of HTN was significantly higher in studies from Southern Africa region of SSA and positively correlated with the year of publication. Across studies, traditional risk factors such as age, sex, body mass index, and physical inactivity, were commonly found to be associated with HTN. In contrast, non-traditional risk factors related to poverty and tropical diseases were rarely assessed. Only three studies investigated the CVD complications related to HTN in the study population.

Conclusion

The prevalence of HTN among adolescents in SSA is high indicating that this is a major health problem. Data on non-traditional risk factors and complications are scarce. Longitudinal studies are needed to clearly define the rates, causes, and complications of HTN.

Systematic Review Registration

https://osf.io/p5sbt/, identifier (10.17605/OSF.IO/P5SBT).

Invited Commentary: Beyond Barker-Mothers Are the Ones at Risk

Dr. David Barker hypothesized that low birth weight (LBW) is the result of inadequate fetal nutrition, leading to increased risk of cardiovascular disease (CVD) in the offspring. This hypothesis has stimulated thousands of reports on low birth weight (LBW) and CVD risk. One problem with this association is that many LBW infants are small because they are preterm, not growth-restricted. A second problem is that maternal CVD risk factors confound the association. In an accompanying article, Lu et al. (Am J Epidemiol. 2023;192(6):866-877) address both concerns. Using population data from Sweden and Denmark, the authors estimated CVD incidence among offspring born small for gestational age (SGA). The smallest 3% had a CVD hazard ratio of 1.44 (95% confidence interval: 1.38, 1.51). Even this moderate risk mostly evaporated in sibship analysis, which controlled for unmeasured maternal CVD risk factors (hazard ratio = 1.11, 95% confidence interval: 0.99, 1.25). The risk highlighted by Barker is negligible, especially when compared with a more urgent health issue-cardiovascular risk in women with pregnancy complications. Mothers of SGA infants have up to a 3-fold CVD risk, and mothers with preeclampsia and preterm delivery have up to a 9-fold risk. Pregnancy complications thus provide an early marker of a woman's propensity to develop CVD, and perhaps an opportunity for early intervention. From a public health perspective, Barker's hypothesis about CVD risk in LBW offspring is less compelling than the question of CVD risk among mothers with pregnancy complications. This article is part of a Special Collection on ABC.

Body Composition and Cardiometabolic Risk Markers in Children of Women who Took Part in a Randomized Controlled Trial of a Pre-conceptional Nutritional Intervention in Mumbai, India

Background

Maternal nutrition influences fetal development and may permanently alter (“program”) offspring body composition and metabolism, thereby influencing later risk of diabetes and cardiovascular (cardiometabolic) disease. The prevalence of cardiometabolic disease is rising rapidly in India.

Objectives

To test the hypothesis that supplementing low-income Indian women with micronutrient-rich foods preconceptionally and during pregnancy has a beneficial impact on the children's body composition and cardiometabolic risk marker profiles.

Methods

Follow-up of 1255 children aged 5–10 y whose mothers took part in the Mumbai Maternal Nutrition Project [Project “SARAS”; International Standard Randomised Controlled Trial Number (ISRCTN)62811278]. Mothers were randomly assigned to receive a daily micronutrient-rich snack or a control snack of lower micronutrient content, both made from local foods, in addition to normal diet, from before pregnancy until delivery. Children's body composition was assessed using anthropometry and DXA. Their blood pressure, plasma glucose, insulin, and lipid concentrations were measured. Outcomes were compared between allocation groups with and without adjustment for confounding factors.

Results

Overall, 15% of children were stunted, 34% were wasted, and 3% were overweight. In the intention-to-treat analysis, there were no differences in body composition or risk markers between children in the intervention and control groups. Among children whose mothers started supplementation ≥3 mo before conception (the “per protocol” sample) the intervention increased adiposity among girls, but not boys. BMI in girls was increased relative to controls by 2% (95% CI: 1, 4; P = 0.01); fat mass index by 10% (95% CI: 3, 18; P = 0.004); and percent fat by 7% (95% CI: 1, 13; P = 0.01) unadjusted, with similar results in adjusted models.

Conclusions

Overall, supplementing women with micronutrient-rich foods from before pregnancy until delivery did not alter body composition or cardiometabolic risk markers in the children. Subgroup analyses showed that, if started ≥3 mo before conception, supplementation may increase adiposity among female children.

Exploring influences on adolescent diet and physical activity in rural Gambia, West Africa: food insecurity, culture and the natural environment

OBJECTIVE

To explore, from the perspectives of adolescents and caregivers, and using qualitative methods, influences on adolescent diet and physical activity in rural Gambia.

DESIGN

Six focus group discussions (FGD) with adolescents and caregivers were conducted. Thematic analysis was employed across the data set.

SETTING

Rural region of The Gambia, West Africa.

PARTICIPANTS

Participants were selected using purposive sampling. Four FGD, conducted with forty adolescents, comprised: girls aged 10-12 years; boys aged 10-12 years; girls aged 15-17 years, boys aged 15-17 years. Twenty caregivers also participated in two FGD (mothers and fathers).

RESULTS

All participants expressed an understanding of the association between salt and hypertension, sugary foods and diabetes, and dental health. Adolescents and caregivers suggested that adolescent nutrition and health were shaped by economic, social and cultural factors and the local environment. Adolescent diet was thought to be influenced by: affordability, seasonality and the receipt of remittances; gender norms, including differences in opportunities afforded to girls, and mother-led decision-making; cultural ceremonies and school holidays. Adolescent physical activity included walking or cycling to school, playing football and farming. Participants felt adolescent engagement in physical activity was influenced by gender, seasonality, cultural ceremonies and, to some extent, the availability of digital media.

CONCLUSIONS

These novel insights into local understanding should be considered when formulating future interventions. Interventions need to address these interrelated factors, including misconceptions regarding diet and physical activity that may be harmful to health.

Effects of vitamin and mineral supplementation during pregnancy on maternal, birth, child health and development outcomes in low- and middle-income countries: A systematic review

Background

Almost two billion people who are deficient in vitamins and minerals are women and children in low- and middle-income countries (LMIC). These deficiencies are worsened during pregnancy due to increased energy and nutritional demands, causing adverse outcomes in mother and child. To reduce micronutrient deficiencies, several strategies have been implemented, including diet diversification, large-scale and targeted fortification, staple crop bio-fortification and micronutrient supplementation.

Objectives

To evaluate and summarize the available evidence on the effects of micronutrient supplementation during pregnancy in LMIC on maternal, fetal, child health and child development outcomes. This review will assess the impact of single micronutrient supplementation (calcium, vitamin A, iron, vitamin D, iodine, zinc, vitamin B12), iron-folic acid (IFA) supplementation, multiple micronutrient (MMN) supplementation, and lipid-based nutrient supplementation (LNS) during pregnancy.

Search Methods

We searched papers published from 1995 to 31 October 2019 (related programmes and good quality studies pre-1995 were limited) in CAB Abstracts, CINAHL, Cochrane Central Register of Controlled Trials, Embase, International Initiative for Impact Evaluations, LILACS, Medline, POPLINE, Web of Science, WHOLIS, ProQuest Dissertations & Theses Global, R4D, WHO International Clinical Trials Registry Platform. Non-indexed grey literature searches were conducted using Google, Google Scholar, and web pages of key international nutrition agencies.

Selection Criteria

We included randomized controlled trials (individual and cluster-randomized) and quasi-experimental studies that evaluated micronutrient supplementation in healthy, pregnant women of any age and parity living in a LMIC. LMIC were defined by the World Bank Group at the time of the search for this review. While the aim was to include healthy pregnant women, it is likely that these populations had one or more micronutrient deficiencies at baseline; women were not excluded on this basis.

Data Collection and Analysis

Two authors independently assessed studies for inclusion and risk of bias, and conducted data extraction. Data were matched to check for accuracy. Quality of evidence was assessed using the GRADE approach.

Main Results

A total of 314 papers across 72 studies (451,723 women) were eligible for inclusion, of which 64 studies (439,649 women) contributed to meta-analyses. Seven studies assessed iron-folic acid (IFA) supplementation versus folic acid; 34 studies assessed MMN vs. IFA; 4 studies assessed LNS vs. MMN; 13 evaluated iron; 13 assessed zinc; 9 evaluated vitamin A; 11 assessed vitamin D; and 6 assessed calcium. Several studies were eligible for inclusion in multiple types of supplementation. IFA compared to folic acid showed a large and significant (48%) reduction in the risk of maternal anaemia (average risk ratio (RR) 0.52, 95% CI 0.41 to 0.66; studies = 5; participants = 15,540; moderate-quality evidence). As well, IFA supplementation demonstrated a smaller but significant, 12% reduction in risk of low birthweight (LBW) babies (average RR 0.88, 95% CI 0.78 to 0.99; studies = 4; participants = 17,257; high-quality evidence). MMN supplementation was defined as any supplement that contained at least 3 micronutrients. Post-hoc analyses were conducted, where possible, comparing the differences in effect of MMN with 4+ components and MMN with 3 or 4 components. When compared to iron with or without FA, MMN supplementation reduced the risk of LBW by 15% (average RR 0.85, 95% CI 0.77 to 0.93; studies = 28; participants = 79,972); this effect was greater in MMN with >4 micronutrients (average RR 0.79, 95% CI 0.71 to 0.88; studies = 19; participants = 68,138 versus average RR 1.01, 95% CI 0.92 to 1.11; studies = 9; participants = 11,834). There was a small and significant reduction in the risk of stillbirths (average RR 0.91; 95% CI 0.86 to 0.98; studies = 22; participants = 96,772) and a small and significant effect on the risk of small-for-gestational age (SGA) (average RR 0.93; 95% CI 0.88 to 0.98; studies = 19; participants = 52,965). For stillbirths and SGA, the effects were greater among those provided MMN with 4+ micronutrients. Children whose mothers had been supplemented with MMN, compared to IFA, demonstrated a 16% reduced risk of diarrhea (average RR 0.84; 95% CI 0.76 to 0.92; studies = 4; participants = 3,142). LNS supplementation, compared to MMN, made no difference to any outcome; however, the evidence is limited. Iron supplementation, when compared to no iron or placebo, showed a large and significant effect on maternal anaemia, a reduction of 47% (average RR 0.53, 95% CI 0.43 to 0.65; studies = 6; participants = 15,737; moderate-quality evidence) and a small and significant effect on LBW (average RR 0.88, 95% CI 0.78 to 0.99; studies = 4; participants = 17,257; high-quality evidence). Zinc and vitamin A supplementation, each both compared to placebo, had no impact on any outcome examined with the exception of potentially improving serum/plasma zinc (mean difference (MD) 0.43 umol/L; 95% CI -0.04 to 0.89; studies = 5; participants = 1,202) and serum/plasma retinol (MD 0.13 umol/L; 95% CI -0.03 to 0.30; studies = 6; participants = 1,654), respectively. When compared to placebo, vitamin D supplementation may have reduced the risk of preterm births (average RR 0.64; 95% CI 0.40 to 1.04; studies = 7; participants = 1,262), though the upper CI just crosses the line of no effect. Similarly, calcium supplementation versus placebo may have improved rates of pre-eclampsia/eclampsia (average RR 0.45; 95% CI 0.19 to 1.06; studies = 4; participants = 9,616), though the upper CI just crosses 1.

Authors' Conclusions

The findings suggest that MMN and vitamin supplementation improve maternal and child health outcomes, including maternal anaemia, LBW, preterm birth, SGA, stillbirths, micronutrient deficiencies, and morbidities, including pre-eclampsia/eclampsia and diarrhea among children. MMN supplementation demonstrated a beneficial impact on the most number of outcomes. In addition, MMN with >4 micronutrients appeared to be more impactful than MMN with only 3 or 4 micronutrients included in the tablet. Very few studies conducted longitudinal analysis on longer-term health outcomes for the child, such as anthropometric measures and developmental outcomes; this may be an important area for future research. This review may provide some basis to guide continual discourse around replacing IFA supplementation with MMN along with the use of single micronutrient supplementation programs for specific outcomes.

Effects of nutritional interventions during pregnancy on birth, child health and development outcomes: A systematic review of evidence from low- and middle-income countries

Background

Optimal nutrition plays a crucial role in pregnancy. Poor maternal nutrition and maternal obesity has risk factors for serious fetal complications and neonatal outcomes, including intrauterine growth restriction, congenital abnormalities, stillbirth, low birth weight (LBW), preterm birth, fetal macrosomia, increased risk of neonatal infections, neonatal hypothermia, and neonatal death. The prevalence of maternal malnutrition is higher in low- and middle-income countries (LMICs) (10-19%) when compared with high-income countries, with variation by region and by country. Several behavioral interventions, including dietary control and exercise, have been found to reduce the risk of these adverse outcomes. However, none has reviewed dietary interventions to prevent maternal obesity in pregnant women.

Objectives

The review aims to assess the effectiveness of balanced energy protein (BEP) supplementation, food distribution programs (FDPs), and dietary interventions to prevent maternal obesity during pregnancy on birth, child health, and developmental outcomes.

Search Methods

We searched Cochrane Controlled Trials Register (CENTRAL), MEDLINE, Embase, CINAHL, and 12 other databases, and trials registers for ongoing studies up until April 2019. We also searched for gray literature from different sources and for citations on Google Scholar and Web of Sciences. We also checked the reference lists of included studies and relevant reviews and contacted the authors of studies for any ongoing and unpublished studies. The search was followed by title/abstract screening, full-text screening and data extraction.

Selection Criteria

We included randomized control trials, and quasi experimental trials to evaluate the impact of nutritional interventions (BEP, FDP, and dietary interventions to prevent maternal obesity) compared to control or standard of care, among healthy pregnant women of any age living in LMICs.

Data Collection and Analysis

Two review authors independently assessed and screened studies for eligibility, extracted data, and assessed quality of the studies included in the review. We conducted a meta-analysis of all reported primary and secondary outcomes. Subgroup analysis and GRADE assessment was performed for all reported primary outcomes.

Main Results

The review included 15 studies, of these, eight were on BEP supplementation, five on FDP, and two on interventions for obesity prevention. BEP supplementation may show a reduction in the rate of stillbirths by 61% (risk ratio [RR], 0.39; 95% CI, 0.19-0.80; three studies, n = 1913; low quality on GRADE), perinatal mortality by 50% (RR, 0.50; 95% CI, 0.30-0.84; one study, n = 1446; low quality on GRADE), LBW infants by 40% (RR, 0.60; 95% CI, 0.41-0.86; three studies, n = 1830; low quality of evidence on GRADE); small for gestational age (SGA) by 29% (RR, 0.71; 95% CI, 0.54-0.94; five studies, n = 1844) and increased birth weight by 107.28 g (mean difference [MD], 107.28 g; 95% CI, 68.51-146.04, eight studies, n = 2190). An increase of 107.28 g of birthweight is clinically significant in the countries where the intervention was provided. BEP supplementation had no effect on miscarriage, neonatal mortality, infant mortality, preterm birth, birth length, and head circumference. FDP may show improvement in mean birth weight by 46 g (MD, 46.00 g; 95% CI, 45.10-46.90, three studies, n = 5272), in birth length by 0.20 cm (MD, 0.20 cm; 95% CI, 0.20-0.20, three studies, n = 5272), and reduction in stunting by 18% (RR, 0.82; 95% CI, 0.71-0.94; two studies; n = 4166), and wasting by 13% (RR, 0.87; 95% CI, 0.78-0.97; two studies, n = 3883). There was no effect of FDP on miscarriage, maternal mortality, perinatal mortality, neonatal mortality, infant mortality, preterm birth, LBW, SGA, head circumference, and underweight babies. Studies on interventions for obesity prevention among pregnant women failed to report on the primary outcomes. The studies showed a 195.57 g reduction in mean birth weight (MD, -195.57 g, 95% CI, -349.46 to -41.68, two studies, n = 180), and had no effect on birth length, and macrosomia.

Authors' Conclusions

Our review highlights improvement in maternal, birth, and child outcomes through BEP supplementation and FDP during pregnancy. But, due to the small number of included studies and low quality of evidence, we are uncertain of the effect of BEP supplementation, FDP and dietary interventions for prevention of obesity on maternal, and child outcomes. Thus, further good quality research is recommended to assess the effect of these interventions on maternal, child and developmental outcomes.

Early-Life Nutrition Interventions and Associated Long-Term Cardiometabolic Outcomes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Early-life nutrition interventions can have lifelong cardiometabolic benefits. Most evidence on this topic is derived from observational studies. We evaluated the association of randomized controlled nutritional trials in early life and long-term cardiometabolic outcomes. Through literature search of PubMed, CABI Global Health, Embase, and Cochrane, with manual reference check and weekly alert from PubMed, we identified 8312 records, and included 53 records from 40 cohorts in 21 countries. The total number of participants was 33,551. Interventions were initiated as early as conception, and the longest until 7 y (except 1 study from infancy to 20 y). The cohorts were followed up for between 3 and 73 y. We identified 7 types of interventions (protein-energy supplements, long-chain PUFAs, single micronutrient, multiple micronutrients, infant and young child feeding, dietary counseling, and other) and 4 categories of cardiometabolic outcomes (biomarkers, cardiovascular, body size and composition, and subclinical/clinical outcomes). Most findings were null. Fasting glucose concentration was 0.04 mmol/L lower (95% CI: -0.05, -0.02 mmol/L; I2 = 0%) in the intervention groups than in the control groups (15 studies). BMI (kg/m2) was 0.20 higher (95% CI: 0.12, 0.28; I2 = 54%) in the intervention groups than control groups (14 studies). No significant effect was observed for total cholesterol (12 studies) or blood pressure (17 studies). Ongoing and personalized dietary counseling was associated with lower glucose and cholesterol, better endothelial function, and reduced risk of metabolic syndrome. The timing of intervention mattered, with earlier initiation conferring greater benefit (improved lipid profile and marginally lower glucose concentration) based on 2 studies. In sum, glucose concentration was lower following early-life nutrition interventions, but there is a risk of unintended consequences, including higher BMI. Maternal and child nutrition interventions must be evidence-based and tailored to each population to promote long-term cardiometabolic health.

Effect of supplemental nutrition in pregnancy on offspring's risk of cardiovascular disease in young adulthood: Long-term follow-up of a cluster trial from India

BACKGROUND

Undernutrition during intrauterine life and early childhood is hypothesised to increase the risk of cardiovascular disease (Developmental Origins of Health and Disease Hypothesis), but experimental evidence from humans is limited. This hypothesis has major implications for control of the cardiovascular disease epidemic in South Asia (home to a quarter of world's population), where a quarter of newborns have low birth weight. We investigated whether, in an area with prevalent undernutrition, supplemental nutrition offered to pregnant women and their offspring below the age of 6 years was associated with a lower risk of cardiovascular disease in the offspring when they were young adults.

METHODS AND FINDINGS

The Hyderabad Nutrition Trial was a community-based nonrandomised controlled intervention trial conducted in 29 villages near Hyderabad, India (1987-1990). Protein-calorie food supplement was offered daily to pregnant and lactating women (2.09 MJ energy and 20-25 g protein) and their offspring (1.25 MJ energy and 8-10 g protein) until the age of six years in the 15 intervention villages, but not in the 14 control villages. A total of 1,826 participants (949 from the intervention villages and 877 from the control villages, representing 70% of the cohort) at a mean age of 21.6 years (62% males) were examined between 2009 and 2012. The mean body mass index (BMI) of the participants was 20 kg/m2 and the mean systolic blood pressure was 115 mm Hg. The age, sex, socioeconomic position, and urbanisation-adjusted effects of intervention (beta coefficients and 95% confidence intervals) on outcomes were as follows: carotid intima-media thickness, 0.01 mm (-0.01 to 0.03), p = 0.36; arterial stiffness (augmentation index), -1.1% (-2.5 to 0.3), p = 0.097; systolic blood pressure, 0.5 mm Hg (-0.6 to 1.6), p = 0.36; BMI, -0.13 kg/m2 (-0.75 to 0.09), p = 0.093; low-density lipoprotein (LDL) cholesterol, 0.06 mmol/L (-0.07 to 0.2), p = 0.37; and fasting insulin (log), -0.06 mU/L (-0.19 to 0.07), p = 0.43. The limitations of this study include nonrandomised allocation of intervention and lack of data on compliance, and potential for selection bias due to incomplete follow-up.

CONCLUSIONS

Our results showed that in an area with prevalent undernutrition, protein-calorie food supplements offered to pregnant women and their offspring below the age of 6 years were not associated with lower levels of cardiovascular risk factors among offspring when they were young adults. Our findings, coupled with evidence from other intervention studies to date, suggest that policy makers should attach limited value to cardiovascular health benefits of maternal and child protein-calorie food supplementation programmes.

The double burden of malnutrition: aetiological pathways and consequences for health

Malnutrition has historically been researched and addressed within two distinct silos, focusing either on undernutrition, food insecurity, and micronutrient deficiencies, or on overweight, obesity, and dietary excess. However, through rapid global nutrition transition, an increasing proportion of individuals are exposed to different forms of malnutrition during the life course and have the double burden of malnutrition (DBM) directly. Long-lasting effects of malnutrition in early life can be attributed to interconnected biological pathways, involving imbalance of the gut microbiome, inflammation, metabolic dysregulation, and impaired insulin signalling. Life-course exposure to early undernutrition followed by later overweight increases the risk of non-communicable disease, by imposing a high metabolic load on a depleted capacity for homoeostasis, and in women increases the risk of childbirth complications. These life-course trajectories are shaped both by societal driving factors-ie, rapidly changing diets, norms of eating, and physical activity patterns-and by broader ecological factors such as pathogen burden and extrinsic mortality risk. Mitigation of the DBM will require major societal shifts regarding nutrition and public health, to implement comprehensive change that is sustained over decades, and scaled up into the entire global food system.

A life history approach to prenatal supplementation: Building a bridge from biological anthropology to public health and nutrition

While prenatal supplementation with protein, lipids, carbohydrates, and micronutrients has been used to improve infant outcomes in undernourished populations since the 1960s with inconsistent results, a flourishing body of literature within biological anthropology has used life history theory to explain why supplemental resources are often allocated to maternal survival and future reproduction and not to the current offspring. To date, however, public health and nutrition researchers have not adopted evolutionary perspectives in designing or analyzing prenatal supplementation studies. The result is a long series of supplementation trials with unpredictable and often disappointing outcomes for women and children, as well as serious lacunae in the understanding of long-term consequences of supplementation for women. The goal of this article is to open a tactical conversation about how to build a bridge between the evolutionary logic of biological anthropology and the evidentiary standards and methods of public health and nutrition with the aim of advancing knowledge about reproductive and metabolic physiology and improving women's health over the life course. The article reviews recent prenatal supplementation studies and proposes programmatic strategies by which biological anthropologists and public health and nutrition workers may collaborate to define different conditions of prenatal supplement resource allocation and to target more effective interventions.

Metabolic programming in early life in humans

An association of low birth weight with an increased risk of adult cardiovascular disease and diabetes led to the developmental origins of health and disease (DOHaD) hypothesis, which proposes that undernutrition during early development permanently 'programmes' organ structure and metabolism, leading to vulnerability to later cardio-metabolic disease. High birth weight caused by maternal gestational diabetes is also associated with later diabetes, suggesting that fetal over-nutrition also has programming effects. Post-natal factors (excess weight gain/obesity, smoking, poor diets and physical inactivity) interact with fetal exposures to increase disease risk. Animal studies have shown permanent metabolic effects in offspring after alterations to maternal or early post-natal diets but evidence in humans is largely limited to observational and quasi-experimental situations such as maternal famine exposure. Randomized trials of maternal nutritional interventions during pregnancy have so far had limited follow-up of the offspring. Moreover, interventions usually started after the first trimester and therefore missed key peri-conceptional or early pregnancy events such as epigenetic changes, placentation and fetal organogenesis. Recent and ongoing trials intervening pre-conceptionally and powered for long-term offspring follow-up will address these issues. While current preventive strategies for cardio-metabolic disease focus on high-risk individuals in mid-life, DOHaD concepts offer a 'primordial' preventive strategy to reduce disease in future generations by improving fetal and infant development. This article is part of the theme issue 'Developing differences: early-life effects and evolutionary medicine'.

Pregnancy supplementation of Gambian mothers with calcium carbonate alters mid-childhood IGF1 in a sex-specific manner

CONTEXT

Sex-specific effects of pregnancy calcium carbonate supplementation have been reported in 8-12 year old Gambian children, indicating faster growth in boys but slower growth in girls born to calcium-supplemented mothers.

OBJECTIVE

To determine whether the pregnancy supplement resulted in sex-specific effects on offspring IGF1 and other growth-related indices in mid-childhood.

DESIGN

Analysis of archived data obtained in mid-childhood from the children of rural Gambian mothers who had been randomised to 1500 mgCa/d (Ca) or placebo (P) from 20 weeks pregnancy to delivery (ISRCTN96502494).

PARTICIPANTS AND METHODS

Of the 526 children born and followed in infancy, 290 had early-morning, fasting plasma assayed for IGF1, IGFBP3, leptin, insulin and calcium-related indices and had anthropometry performed at age 7.5 (SD1.2) years (N/group: Males(M)-Ca = 64, Females(F)-Ca = 77; M-P = 76, F-P = 73). Sex-specific effects of maternal supplementation were considered using regression with sexes separated and together to test for sex ∗ supplement interactions.

RESULTS

Boys had lower IGF1, IGFBP3, leptin and insulin than girls (P ≤ 0.004). IGF1 was higher in M-Ca than M-P (+14.2 (SE7.7)%, P = 0.05) but lower in F-Ca than F-P (-17.8 (SE7.4)%, P = 0.01); sex ∗ supplement interaction P = 0.001. IGF1 concentrations (ng/ml, geometric mean [-1SE,+1SE]) were M-Ca = 78.1[4.3,4.5], M-P = 67.8[3.4,3.6]; F-Ca = 99.5[4.8,5.1], F-P = 118.9[6.4,6.8]. Similar sex ∗ supplement interactions were seen for IGFBP3 and IGF1-adjusted-for-IGFBP3 but group differences were smaller. There were no significant supplement effects on the other biochemical indices.

CONCLUSIONS

Calcium carbonate supplementation of pregnant Gambian mothers resulted in higher IGF1 in boys and lower IGF1 in girls during mid-childhood, consistent with the reported maternal supplement effects on growth of the offspring in later childhood.

Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems

BACKGROUND

Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia, and may help to prevent preterm birth. This is an update of a review last published in 2014.

OBJECTIVES

To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (18 September 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), including cluster-randomised trials, comparing high-dose calcium supplementation (at least 1 g daily of calcium) during pregnancy with placebo. For low-dose calcium we included quasi-randomised trials, trials without placebo, trials with cointerventions and dose comparison trials.

DATA COLLECTION AND ANALYSIS

Two researchers independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Two researchers assessed the evidence using the GRADE approach.

MAIN RESULTS

We included 27 studies (18,064 women). We assessed the included studies as being at low risk of bias, although bias was frequently difficult to assess due to poor reporting and inadequate information on methods.High-dose calcium supplementation (≥ 1 g/day) versus placeboFourteen studies examined this comparison, however one study contributed no data. The 13 studies contributed data from 15,730 women to our meta-analyses. The average risk of high blood pressure (BP) was reduced with calcium supplementation compared with placebo (12 trials, 15,470 women: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.53 to 0.81; I² = 74%). There was also a reduction in the risk of pre-eclampsia associated with calcium supplementation (13 trials, 15,730 women: average RR 0.45, 95% CI 0.31 to 0.65; I² = 70%; low-quality evidence). This effect was clear for women with low calcium diets (eight trials, 10,678 women: average RR 0.36, 95% CI 0.20 to 0.65; I² = 76%) but not those with adequate calcium diets. The effect appeared to be greater for women at higher risk of pre-eclampsia, though this may be due to small-study effects (five trials, 587 women: average RR 0.22, 95% CI 0.12 to 0.42). These data should be interpreted with caution because of the possibility of small-study effects or publication bias. In the largest trial, the reduction in pre-eclampsia was modest (8%) and the CI included the possibility of no effect.The composite outcome maternal death or serious morbidity was reduced with calcium supplementation (four trials, 9732 women; RR 0.80, 95% CI 0.66 to 0.98). Maternal deaths were no different (one trial of 8312 women: one death in the calcium group versus six in the placebo group). There was an anomalous increase in the risk of HELLP syndrome in the calcium group (two trials, 12,901 women: RR 2.67, 95% CI 1.05 to 6.82, high-quality evidence), however, the absolute number of events was low (16 versus six).The average risk of preterm birth was reduced in the calcium supplementation group (11 trials, 15,275 women: RR 0.76, 95% CI 0.60 to 0.97; I² = 60%; low-quality evidence); this reduction was greatest amongst women at higher risk of developing pre-eclampsia (four trials, 568 women: average RR 0.45, 95% CI 0.24 to 0.83; I² = 60%). Again, these data should be interpreted with caution because of the possibility of small-study effects or publication bias. There was no clear effect on admission to neonatal intensive care. There was also no clear effect on the risk of stillbirth or infant death before discharge from hospital (11 trials, 15,665 babies: RR 0.90, 95% CI 0.74 to 1.09).One study showed a reduction in childhood systolic BP greater than 95th percentile among children exposed to calcium supplementation in utero (514 children: RR 0.59, 95% CI 0.39 to 0.91). In a subset of these children, dental caries at 12 years old was also reduced (195 children, RR 0.73, 95% CI 0.62 to 0.87).Low-dose calcium supplementation (< 1 g/day) versus placebo or no treatmentTwelve trials (2334 women) evaluated low-dose (usually 500 mg daily) supplementation with calcium alone (four trials) or in association with vitamin D (five trials), linoleic acid (two trials), or antioxidants (one trial). Most studies recruited women at high risk for pre-eclampsia, and were at high risk of bias, thus the results should be interpreted with caution. Supplementation with low doses of calcium reduced the risk of pre-eclampsia (nine trials, 2234 women: RR 0.38, 95% CI 0.28 to 0.52). There was also a reduction in high BP (five trials, 665 women: RR 0.53, 95% CI 0.38 to 0.74), admission to neonatal intensive care unit (one trial, 422 women, RR 0.44, 95% CI 0.20 to 0.99), but not preterm birth (six trials, 1290 women, average RR 0.83, 95% CI 0.34 to 2.03), or stillbirth or death before discharge (five trials, 1025 babies, RR 0.48, 95% CI 0.14 to 1.67).High-dose (=/> 1 g) versus low-dose (< 1 g) calcium supplementationWe included one trial with 262 women, the results of which should be interpreted with caution due to unclear risk of bias. Risk of pre-eclampsia appeared to be reduced in the high-dose group (RR 0.42, 95% CI 0.18 to 0.96). No other differences were found (preterm birth: RR 0.31, 95% CI 0.09 to 1.08; eclampsia: RR 0.32, 95% CI 0.07 to 1.53; stillbirth: RR 0.48, 95% CI 0.13 to 1.83).

AUTHORS' CONCLUSIONS

High-dose calcium supplementation (≥ 1 g/day) may reduce the risk of pre-eclampsia and preterm birth, particularly for women with low calcium diets (low-quality evidence). The treatment effect may be overestimated due to small-study effects or publication bias. It reduces the occurrence of the composite outcome 'maternal death or serious morbidity', but not stillbirth or neonatal high care admission. There was an increased risk of HELLP syndrome with calcium supplementation, which was small in absolute numbers.The limited evidence on low-dose calcium supplementation suggests a reduction in pre-eclampsia, hypertension and admission to neonatal high care, but needs to be confirmed by larger, high-quality trials.

High blood pressure and associated risk factors as indicator of preclinical hypertension in rural West Africa: A focus on children and adolescents in The Gambia

Hypertension is fast becoming a major public health problem across sub-Saharan Africa. We sought to determine the prevalence of high blood pressure (BP) and associated risk factors as indicator of preclinical hypertension in a rural Gambian population.We analyzed data on 6160 healthy Gambians cross-sectionally. Attention was given to 5 to <18-year olds (N = 3637), as data from sub-Saharan Africa on this young age group are scarce. High BP was defined as systolic blood pressure (SBP) above the 95th percentile for age-sex specific height z scores in <18-year olds employing population-specific reference values. Standard high BP categories were applied to ≥18-year olds.In <18-year olds, the multivariable analysis gave an adjusted high BP prevalence ratio of 0.95 (95% confidence interval [CI] 0.92-0.98; P = 0.002) for age and 1.13 (95% CI 1.06-1.19; P < 0.0001) for weight-for-height z score (zWT-HT); sex and hemoglobin were not shown to affect high BP. In adults age 1.05 (95% CI 1.04-1.05; P < 0.0001), body mass index z score 1.28 (95% CI 1.16-1.40; P < 0.0001), hemoglobin 0.90 (95% CI 0.85-0.96; P < 0.0001) and high fasting glucose 2.60 (95% CI 2.02-3.36; P < 0.0001, though the number was very low) were confirmed as risk factors for high BP prevalence; sex was not associated.The reported high BP prevalence and associated risk factors in adults are comparable to other studies conducted in the region. The observed high BP prevalence of 8.2% (95% CI 7.4-9.2) in our generally lean young Gambians (<18 years) is alarming, given that high BP tracks from childhood to adulthood. Hence there is an urgent need for further investigation into risk factors of pediatric high BP/hypertension even in rural African settings.

Effects of prenatal micronutrient and early food supplementation on metabolic status of the offspring at 4.5 years of age. The MINIMat randomized trial in rural Bangladesh

Background: Fetal nutritional insults may alter the later metabolic phenotype. We hypothesized that early timing of prenatal food supplementation and multiple micronutrient supplementation (MMS) would favourably influence childhood metabolic phenotype.

Methods: Pregnant women recruited 1 January to 31 December 2002 in Matlab, Bangladesh, were randomized into supplementation with capsules of either 30 mg of iron and 400 μg of folic acid, 60 mg of iron and 400 μg of folic acid, or MMS containing a daily allowance of 15 micronutrients, and randomized to food supplementation (608 kcal) either with early invitation (9 weeks’ gestation) or usual invitation (at 20 weeks). Their children (n = 1667) were followed up at 4.5 years with assessment of biomarkers of lipid and glucose metabolism, inflammation and oxidative stress.

Results: Children in the group with early timing of food supplementation had lower cholesterol (difference -0.079 mmol/l, 95% confidence interval (CI) -0.156; -0.003), low-density lipoprotein (LDL) (difference -0.068 mmol/l, 95% CI -0.126; -0.011) and ApoB levels (difference -0.017 g/l, 95% CL -0.033; -0.001). MMS supplementation resulted in lower high-density lipoprotein (HDL) (difference -0.028 mmol/l, 95% CL -0.053; -0.002), lower glucose (difference -0.099 mmol/l, 95% CL -0.179; -0.019) and lower insulin-like growth factor 1 (IGF-1) (difference on log scale -0.141 µg/l, 95% CL -0.254; -0.028) than 60 mg iron and 400 μg folic acid. There were no effects on markers of inflammation or oxidative stress.

Conclusions: Findings suggest that in a population where malnutrition is prevalent, nutrition interventions during pregnancy may modify the metabolic phenotype in the young child that could have consequences for later chronic disease risks.

Tackling malnutrition: a systematic review of 15-year research evidence from INDEPTH health and demographic surveillance systems

Background

Nutrition is the intake of food in relation to the body's dietary needs. Malnutrition results from the intake of inadequate or excess food. This can lead to reduced immunity, increased susceptibility to disease, impaired physical and mental development, and reduced productivity.

Objective

To perform a systematic review to assess research conducted by the International Network for the Demographic Evaluation of Populations and their Health (INDEPTH) of health and demographic surveillance systems (HDSSs) over a 15-year period on malnutrition, its determinants, the effects of under and over nutrition, and intervention research on malnutrition in low- and middle-income countries (LMICs).

Methods

Relevant publication titles were uploaded onto the Zotero research tool from different databases (60% from PubMed). Using the keywords ‘nutrition’, ‘malnutrition’, ‘over and under nutrition’, we selected publications that were based only on data generated through the longitudinal HDSS platform. All titles and abstracts were screened to determine inclusion eligibility and full articles were independently assessed according to inclusion/exclusion criteria. For inclusion in this study, papers had to cover research on at least one of the following topics: the problem of malnutrition, its determinants, its effects, and intervention research on malnutrition. One hundred and forty eight papers were identified and reviewed, and 67 were selected for this study.

Results

The INDEPTH research identified rising levels of overweight and obesity, sometimes in the same settings as under-nutrition. Urbanisation appears to be protective against under-nutrition, but it heightens the risk of obesity. Appropriately timed breastfeeding interventions were protective against malnutrition.

Conclusions

Although INDEPTH has expanded the global knowledge base on nutrition, many questions remain unresolved. There is a need for more investment in nutrition research in LMICs in order to generate evidence to inform policies in these settings.

Review of the importance of nutrition during the first 1000 days: maternal nutritional status and its associations with fetal growth and birth, neonatal and infant outcomes among African women

Maternal nutritional status (MNS) is a strong predictor of growth and development in the first 1000 days of life and may influence susceptibility to non-communicable diseases in adulthood. However, the role of nutrition during this window of developmental plasticity in Africa is unclear. This paper reviews published data to address whether maternal nutrition during the first 1000 days is important for Africa, with a focus on MNS and its associations with fetal growth and birth, neonatal and infant outcomes. A systematic approach was used to search the following databases: Medline, EMBASE, Web of Science, Google Scholar, ScienceDirect, SciSearch and Cochrane Library. In all, 26 studies met the inclusion criteria for the specific objectives. MNS in Africa showed features typical of the epidemiological transition: higher prevalences of maternal overweight and obesity and lower underweight, poor diet quality 1 and high anaemia prevalence. Maternal body mass index and greater gestational weight gain (GWG) were positively associated with birth weight; however, maternal overweight and obesity were associated with increased risk of macrosomia and intrauterine growth restriction. Maternal anaemia was associated with lower birth weight. Macro- and micronutrient supplementation during pregnancy were associated with improvements in GWG, birth weight and mortality risk. Data suggest poor MNS in Africa and confirms the importance of the first 1000 days as a critical period for nutritional intervention to improve growth, birth outcomes and potential future health risk. However, there is a lack of data beyond birth and a need for longitudinal data through infancy to 2 years of age.

Antenatal dietary education and supplementation to increase energy and protein intake

BACKGROUND

Gestational weight gain is positively associated with fetal growth, and observational studies of food supplementation in pregnancy have reported increases in gestational weight gain and fetal growth.

OBJECTIVES

To assess the effects of education during pregnancy to increase energy and protein intake, or of actual energy and protein supplementation, on energy and protein intake, and the effect on maternal and infant health outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2015), reference lists of retrieved studies and contacted researchers in the field.

SELECTION CRITERIA

Randomised controlled trials of dietary education to increase energy and protein intake, or of actual energy and protein supplementation, during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed risk of bias. Two review authors independently extracted data and checked for accuracy. Extracted data were supplemented by additional information from the trialists we contacted.

MAIN RESULTS

We examined 149 reports corresponding to 65 trials. Of these trials, 17 were included, 46 were excluded, and two are ongoing. Overall, 17 trials involving 9030 women were included. For this update, we assessed methodological quality of the included trials using the standard Cochrane criteria (risk of bias) and the GRADE approach. The overall risk of bias was unclear. Nutritional education (five trials, 1090 women) Women given nutritional education had a lower relative risk of having a preterm birth (two trials, 449 women) (risk ratio (RR) 0.46, 95% CI 0.21 to 0.98, low-quality evidence), and low birthweight (one trial, 300 women) (RR 0.04, 95% CI 0.01 to 0.14). Head circumference at birth was increased in one trial (389 women) (mean difference (MD) 0.99 cm, 95% CI 0.43 to 1.55), while birthweight was significantly increased among undernourished women in two trials (320 women) (MD 489.76 g, 95% CI 427.93 to 551.59, low-quality evidence), but did not significantly increase for adequately nourished women (MD 15.00, 95% CI -76.30 to 106.30, one trial, 406 women). Protein intake increased significantly (three trials, 632 women) (protein intake: MD +6.99 g/day, 95% CI 3.02 to 10.97). No significant differences were observed on any other outcomes such as neonatal death (RR 1.28, 95% CI 0.35 to 4.72, one trial, 448 women, low-quality evidence), stillbirth (RR 0.37, 95% CI 0.07 to 1.90, one trial, 431 women, low-quality evidence), small-for-gestational age (RR 0.97, 95% CI 0.45 to 2.11, one trial, 404 women, low-quality evidence) and total gestational weight gain (MD -0.41, 95% CI -4.41 to 3.59, two trials, 233 women). There were no data on perinatal death. Balanced energy and protein supplementation (12 trials, 6705 women)Risk of stillbirth was significantly reduced for women given balanced energy and protein supplementation (RR 0.60, 95% CI 0.39 to 0.94, five trials, 3408 women, moderate-quality evidence), and the mean birthweight was significantly increased (random-effects MD +40.96 g, 95% CI 4.66 to 77.26, Tau² = 1744, I² = 44%, 11 trials, 5385 women, moderate-quality evidence). There was also a significant reduction in the risk of small-for-gestational age (RR 0.79, 95% CI 0.69 to 0.90, I² = 16%, seven trials, 4408 women, moderate-quality evidence). No significant effect was detected for preterm birth (RR 0.96, 95% CI 0.80 to 1.16, five trials, 3384 women, moderate-quality evidence) or neonatal death (RR 0.68, 95% CI 0.43 to 1.07, five trials, 3381 women, low-quality evidence). Weekly gestational weight gain was not significantly increased (MD 18.63, 95% CI -1.81 to 39.07, nine trials, 2391 women, very low quality evidence). There were no data reported on perinatal death and low birthweight. High-protein supplementation (one trial, 1051 women)High-protein supplementation (one trial, 505 women), was associated with a significantly increased risk of small-for-gestational age babies (RR 1.58, 95% CI 1.03 to 2.41, moderate-quality evidence). There was no significant effect for stillbirth (RR 0.81, 95% CI 0.31 to 2.15, one trial, 529 women), neonatal death (RR 2.78, 95% CI 0.75 to 10.36, one trial, 529 women), preterm birth (RR 1.14, 95% CI 0.83 to 1.56, one trial, 505 women), birthweight (MD -73.00, 95% CI -171.26 to 25.26, one trial, 504 women) and weekly gestational weight gain (MD 4.50, 95% CI -33.55 to 42.55, one trial, 486 women, low-quality evidence). No data were reported on perinatal death. Isocaloric protein supplementation (two trials, 184 women)Isocaloric protein supplementation (two trials, 184 women) had no significant effect on birthweight (MD 108.25, 95% CI -220.89 to 437.40) and weekly gestational weight gain (MD 110.45, 95% CI -82.87 to 303.76, very low-quality evidence). No data reported on perinatal mortality, stillbirth, neonatal death, small-for-gestational age, and preterm birth.

AUTHORS' CONCLUSIONS

This review provides encouraging evidence that antenatal nutritional education with the aim of increasing energy and protein intake in the general obstetric population appears to be effective in reducing the risk of preterm birth, low birthweight, increasing head circumference at birth, increasing birthweight among undernourished women, and increasing protein intake. There was no evidence of benefit or adverse effect for any other outcome reported.Balanced energy and protein supplementation seems to improve fetal growth, and may reduce the risk of stillbirth and infants born small-for-gestational age. High-protein supplementation does not seem to be beneficial and may be harmful to the fetus. Balanced-protein supplementation alone had no significant effects on perinatal outcomes.The results of this review should be interpreted with caution. The risk of bias was either unclear or high for at least one category examined in several of the included trials, and the quality of the evidence was low for several important outcomes. Also, as the anthropometric characteristics of the general obstetric population is changing, those developing interventions aimed at altering energy and protein intake should ensure that only those women likely to benefit are included. Large, well-designed randomised trials are needed to assess the effects of increasing energy and protein intake during pregnancy in women whose intake is below recommended levels.

Calcium supplementation (other than for preventing or treating hypertension) for improving pregnancy and infant outcomes

BACKGROUND

Maternal nutrition during pregnancy is known to have an effect on fetal growth and development. It is recommended that women increase their calcium intake during pregnancy and lactation, although the recommended dosage varies among professionals. Currently, there is no consensus on the role of routine calcium supplementation for pregnant women other than for preventing or treating hypertension.

OBJECTIVES

To determine the effect of calcium supplementation on maternal, fetal and neonatal outcomes (other than for preventing or treating hypertension) as well as any possible side effects.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30th September 2014).

SELECTION CRITERIA

We considered all published, unpublished and ongoing randomised controlled trials (RCTs) comparing maternal, fetal and neonatal outcomes in pregnant women who received calcium supplementation versus placebo or no treatment. Cluster-RCTs were eligible for inclusion but none were identified. Quasi-RCTs and cross-over studies were not eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

Twenty-five studies met the inclusion criteria, but only 23 studies contributed data to the review. These 23 trials recruited 18,587 women, with 17,842 women included in final analyses. There were no statistically significant differences between women who received calcium supplementation and those who did not in terms of reducing preterm births less than 37 weeks' gestation (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.70 to 1.05; 13 studies, 16,139 women; random-effects model) or less than 34 weeks' gestation (RR 1.04, 95% CI 0.80 to 1.36; four trials, 5669). Most studies were of low risk of bias. We conducted sensitivity analysis for the outcome of preterm birth less than 37 weeks by removing two trials with unclear risk of bias for allocation concealment; the results then favoured treatment with calcium supplementation (RR 0.80, 95% CI 0.65 to 0.99; 11 trials, 15,379 women). There was no significant difference in infant low birthweight between the two treatment groups (RR 0.93, 95% CI 0.81 to 1.07; six trials, 14,162 infants; random-effects model). However, when compared to the control group, women in the calcium supplementation group gave birth to slightly heavier birthweight infants (mean difference 56.40, 95% CI 13.55 to 99.25; 21 trials, 9202 women; random-effects model).Three outcomes were chosen for assessment with the GRADE software: preterm birth less than 37 weeks; preterm birth less than 34 weeks; and low birthweight less than 2500 g. Evidence for these outcomes was assessed as of moderate quality.

AUTHORS' CONCLUSIONS

This review indicates that there are no clear additional benefits to calcium supplementation in prevention of preterm birth or low infant birthweight. While there was a statistically significant difference of 56 g identified in mean infant birthweight, there was significant heterogeneity identified, and the clinical significance of this difference is uncertain.

Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems

BACKGROUND

Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia, and may help to prevent preterm birth.

OBJECTIVES

To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 March 2013) and contacted study authors for more data where possible. We updated the search in May 2014 and added the results to the 'Awaiting Classification' section of the review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing high-dose (at least 1 g daily of calcium) or low-dose calcium supplementation during pregnancy with placebo or no calcium.

DATA COLLECTION AND ANALYSIS

We assessed eligibility and trial quality, extracted and double-entered data.

MAIN RESULTS

High-dose calcium supplementation (≥1 g/day)We included 14 studies in the review, however one study contributed no data. We included 13 high-quality studies in our meta-analyses (15,730 women). The average risk of high blood pressure (BP) was reduced with calcium supplementation compared with placebo (12 trials, 15,470 women: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.53 to 0.81; I² = 74%). There was also a significant reduction in the risk of pre-eclampsia associated with calcium supplementation (13 trials, 15,730 women: RR 0.45, 95% CI 0.31 to 0.65; I² = 70%). The effect was greatest for women with low calcium diets (eight trials, 10,678 women: average RR 0.36, 95% CI 0.20 to 0.65; I² = 76%) and women at high risk of pre-eclampsia (five trials, 587 women: average RR 0.22, 95% CI 0.12 to 0.42; I² = 0%). These data should be interpreted with caution because of the possibility of small-study effect or publication bias.The composite outcome maternal death or serious morbidity was reduced (four trials, 9732 women; RR 0.80, 95% CI 0.65 to 0.97; I² = 0%). Maternal deaths were not significantly different (one trial of 8312 women: calcium group one death versus placebo group six deaths). There was an anomalous increase in the risk of HELLP (haemolysis, elevated liver enzymes and low platelets) syndrome (two trials, 12,901 women: RR 2.67, 95% CI 1.05 to 6.82; I² = 0%) in the calcium group, however, the absolute number of events was low (16 versus six).The average risk of preterm birth was reduced in the calcium group (11 trials, 15,275 women: RR 0.76, 95% CI 0.60 to 0.97; I² = 60%) and amongst women at high risk of developing pre-eclampsia (four trials, 568 women: average RR 0.45, 95% CI 0.24 to 0.83; I² = 60%), but no significant reduction in neonatal high care admission. There was no overall effect on the risk of stillbirth or infant death before discharge from hospital (11 trials 15,665 babies: RR 0.90, 95% CI 0.74 to 1.09; I² = 0%).One study showed a reduction in childhood systolic BP greater than 95th percentile among children exposed to calcium supplementation in utero (514 children: RR 0.59, 95% CI 0.39 to 0.91). In a subset of these children, dental caries at 12 years old was also reduced (195 children, RR 0.73, 95% CI 0.62 to 0.87). Low-dose calcium supplementation (< 1 g/day)We included 10 trials (2234 women) that evaluated low-dose supplementation with calcium alone (4) or in association with vitamin D (3), linoleic acid (2), or antioxidants (1). Most studies recruited women at high risk for pre-eclampsia, and were at high risk of bias, thus the results should be interpreted with caution. Supplementation with low doses of calcium significantly reduced the risk of pre-eclampsia (RR 0.38, 95% CI 0.28 to 0.52; I² = 0%). There was also a reduction in hypertension, low birthweight and neonatal intensive care unit admission.

AUTHORS' CONCLUSIONS

Calcium supplementation (≥ 1 g/day) is associated with a significant reduction in the risk of pre-eclampsia, particularly for women with low calcium diets. The treatment effect may be overestimated due to small-study effects or publication bias. It also reduces preterm birth and the occurrence of the composite outcome 'maternal death or serious morbidity'. We considered these benefits to outweigh the increased risk of HELLP syndrome, which was small in absolute numbers. The World Health Organization recommends calcium 1.5 g to 2 g daily for pregnant women with low dietary calcium intake.The limited evidence on low-dose calcium supplementation suggests a reduction in pre-eclampsia, but needs to be confirmed by larger, high-quality trials. Pending such results, in settings of low dietary calcium where high-dose supplementation is not feasible, the option of lower-dose supplements (500 to 600 mg/day) might be considered in preference to no supplementation.

The case for establishing a Holocaust survivors cohort in Israel

In this issue, Keinan-Boker summarises the main studies that have followed up offspring of women exposed to famine during pregnancy and calls for the establishment of a national cohort of Holocaust survivors and their offspring to study inter-generational effects. She suggests that the study would consolidate the fetal origins theory and lead to translational applications to deal with the inter-generational effects of the Holocaust. Barker suggested that alterations in the nutritional supply during critical stages of intra-uterine development permanently alter the structure and metabolism of fetal organs which he termed 'fetal programming' (now known as developmental origins of health and disease). The famine studies have played an important role in refining the hypothesis by allowing a 'quasi-experimental' setting that would otherwise have been impossible to recreate. The developmental origins hypothesis provides a framework to link genetic, environmental and social factors across the lifecourse and offers a primordial preventive strategy to prevent non-communicable disease. Although the famine studies have provided valuable information, the results from various studies are inconsistent. It is perhaps unsurprising given the problems with collecting and interpreting data from famine studies. Survival bias and information bias are key issues. With mortality rates being high, survivors may differ significantly from non-survivors in factors which influence disease development. Most of the data is at ecological level; a lack of individual-level data and poor records make it difficult to identify those affected and assess the severity of effect. Confounding is also possible due to the varying periods and degrees of food deprivation, physical punishment and mental stress undergone by famine survivors. Nonetheless, there would be value in setting up a cohort of Holocaust survivors and their offspring and Keinan-Boker correctly argues that they deserve special attention. National support is essential as the study may re-open old wounds. The study will need to be appropriately planned and resourced. If properly designed, it may provide further insight into the developmental origins hypothesis and suggest translational applications. It may also influence provision of support to women and children affected by man-made wars and famines that continue to happen across the world.

Supplemental feeding during pregnancy compared with maternal supplementation during lactation does not affect schooling and cognitive development through late adolescence

BACKGROUND

The long-term impact of early malnutrition on human capital outcomes remains unclear, and existing evidence has come largely from observational studies.

OBJECTIVE

We compared the impact of a nutritional supplement given during pregnancy or lactation in rural Gambia on educational performance and cognitive ability in offspring at their maturity.

DESIGN

This study was a follow-up of a randomized trial of prenatal high protein and energy supplementation conducted between 1989 and 1994. Subjects were 16-22 y of age at follow-up, and information was collected on schooling achievement and cognitive ability by using the Raven's progressive matrices test, Mill Hill vocabulary test, and forward and backward digit-span tests.

RESULTS

A total of 1459 individuals were traced and interviewed and represented 71% of the original cohort and 81% of the surviving cohort. There was no difference in cognitive ability or educational attainment between treatment groups by using any of the methods of assessment.

CONCLUSION

We have shown little evidence to support a long-term effect of prenatal protein-energy supplementation compared with supplementation during lactation on cognitive development in rural Gambians. This trial was registered at http://www.controlled-trials.com as ISRCTN72582014.

Cohort profile: Andhra Pradesh Children and Parents Study (APCAPS)

The Andhra Pradesh Children and Parents Study (APCAPS) was originally established to study the long-term effects of early-life undernutrition on risk of cardiovascular disease. Its aims were subsequently expanded to include trans-generational influences of other environmental and genetic factors on chronic diseases in rural India. It builds on the Hyderabad Nutrition Trial (HNT) conducted in 1987–90 to compare the effects on birthweight of a protein-calorie supplement for pregnant women and children. The index children of HNT and their mothers were retraced and examined in 2003–05, and the children re-examined as young adults aged 18–21 years in 2009–10. The cohort was expanded to include both parents and siblings of the index children in a recently completed follow-up conducted in 2010–12 (N = ∼6225 out of 10 213 participants). Recruitment of the remaining residents of these 29 villages (N = ∼55 000) in Ranga Reddy district of Andhra Pradesh is now under way. Extensive data on socio-demographic, lifestyle, medical, anthropometric, physiological, vascular and body composition measures, DNA, stored plasma, and assays of lipids and inflammatory markers on APCAPS participants are available. Details of how to access these data are available from the corresponding author.

Combined food and micronutrient supplements during pregnancy have limited impact on child blood pressure and kidney function in rural Bangladesh

Observational evidence suggests nutritional exposures during in utero development may have long-lasting consequences for health; data from interventions are scarce. Here, we present a trial follow-up study to assess the association between prenatal food and micronutrient supplementation and childhood blood pressure and kidney function. During the MINIMat Trial in rural Bangladesh, women were randomly assigned early in pregnancy to receive an early or later invitation to attend a food supplementation program and additionally to receive either iron and folate or multiple micronutrient tablets daily. The 3267 singleton birth individuals with measured anthropometry born during the trial were eligible for a follow-up study at 4.5 y old. A total of 77% of eligible individuals were recruited and blood pressure, kidney size by ultrasound, and glomerular filtration rate (GFR; calculated from plasma cystatin c) were assessed. In adjusted analysis, early invitation to food supplementation was associated with a 0.72-mm Hg [(95% CI: 0.16, 1.28); P = 0.01] lower childhood diastolic blood pressure and maternal MMS supplementation was associated with a marginally higher [0.87 mm Hg (95% CI: 0.18, 1.56); P = 0.01] childhood diastolic blood pressure. There was also some evidence that a supplement higher in iron was associated with a higher offspring GFR. No other effects of the food or micronutrient interventions were observed and there was no interaction between the interventions on the outcomes studied. These marginal associations and small effect sizes suggest limited public health importance in early childhood.

Fetal programming and the risk of noncommunicable disease

The "developmental origins of health and disease" (DOHaD) hypothesis proposes that environmental conditions during fetal and early post-natal development influence lifelong health and capacity through permanent effects on growth, structure and metabolism. This has been called 'programming'. The hypothesis is supported by epidemiological evidence in humans linking newborn size, and infant growth and nutrition, to adult health outcomes, and by experiments in animals showing that maternal under- and over-nutrition and other interventions (e.g., glucocorticoid exposure) during pregnancy lead to abnormal metabolism and body composition in the adult offspring. Early life programming is now thought to be important in the etiology of obesity, type 2 diabetes, and cardiovascular disease, opening up the possibility that these common diseases could be prevented by achieving optimal fetal and infant development. This is likely to have additional benefits for infant survival and human capital (e.g., improved cognitive performance and physical work capacity). Fetal nutrition is influenced by the mother's diet and body size and composition, but hard evidence that the nutrition of the human mother programmes chronic disease risk in her offspring is currently limited. Recent findings from follow-up of children born after randomised nutritional interventions in pregnancy are mixed, but show some evidence of beneficial effects on vascular function, lipid concentrations, glucose tolerance and insulin resistance. Work in experimental animals suggests that epigenetic phenomena, whereby gene expression is modified by DNA methylation, and which are sensitive to the nutritional environment in early life, may be one mechanism underlying programming.

Early exposure to toxic metals has a limited effect on blood pressure or kidney function in later childhood, rural Bangladesh

BACKGROUND

Chronic exposure to toxic metals such as arsenic and cadmium has been implicated in the development of kidney and cardiovascular diseases but few studies have directly measured exposure during inutero and early child development.

METHODS

We investigated the impact of exposure to arsenic (mainly in drinking water) and cadmium (mainly in rice) during pregnancy on blood pressure and kidney function at 4.5 years of age in rural Bangladesh. The effect of arsenic exposure in infancy was also assessed.

RESULTS

Within a cohort of 1887 children recruited into the MINIMat study, exposure to arsenic (maternal urinary arsenic, U-As), but not cadmium, during in utero development was associated with a minimal increase in blood pressure at 4.5 years. Each 1 mg/l increase in pregnancy U-As was associated with 3.69 mmHg (95% CI: 0.74, 6.63; P: 0.01) increase in child systolic and a 2.91 mmHg (95% CI: 0.41, 5.42; P: 0.02) increase in child diastolic blood pressure. Similarly, a 1 mg/l increase in child U-As at 18 months of age was associated with a 8.25 mmHg (95% CI: 1.37, 15.1; P: 0.02) increase in systolic blood pressure at 4.5 years. There was also a marginal inverse association between infancy U-As and glomerular filtration rate at 4.5 years (-33.4 ml/min/1.72 m(2); 95% CI: -70.2, 3.34; P: 0.08). No association was observed between early arsenic or cadmium exposure and kidney volume at 4.5 years assessed by ultrasound.

CONCLUSIONS

These modest effect sizes provide some evidence that arsenic exposure in early life has long-term consequences for blood pressure and maybe kidney function.

Early determinants of chronic disease in developing countries

The prevalence of non-communicable diseases (NCDs) is rising in developing countries. The extent to which this is due to a nutritional mismatch in foetal and adult life is unknown however, studies in such countries show that the risk of chronic diseases is increased in low birthweight subjects who become obese adults. Immune dysfunction is also linked to low birthweight. Therefore, in countries where communicable diseases are prevalent, infection may be exacerbated by factors acting in utero. It is also possible that the foetal growth-retarding effects of maternal Human Immunodeficiency Virus (HIV) and malaria infection may contribute to an increased risk of NCDs later in life. Low birthweight and postnatal growth faltering followed by rapid weight gain define subjects who develop NCDs. Dietary interventions at specific time points in the life course may therefore be important for reducing disease risk.

Antenatal dietary advice and supplementation to increase energy and protein intake

BACKGROUND

Gestational weight gain is positively associated with fetal growth, and observational studies of food supplementation in pregnancy have reported increases in gestational weight gain and fetal growth.

OBJECTIVES

To assess the effects of advice during pregnancy to increase energy and protein intake, or of actual energy and protein supplementation, on energy and protein intakes, and the effect on maternal and infant health outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (22 July 2011) and contacted researchers in the field. We updated the search on 12 July 2012 and added the results to the awaiting classification section of the review.

SELECTION CRITERIA

Randomised controlled trials of dietary advice to increase energy and protein intake, or of actual energy and protein supplementation, during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed risk of bias. Two review authors independently extracted data and checked for accuracy. Extracted data were supplemented by additional information from the trialists we contacted.

MAIN RESULTS

We examined 110 reports corresponding to 46 trials. Of these trials, 15 were included, 30 were excluded, and one is ongoing. Overall, 15 trials involving 7410 women were included.Nutritional advice (four trials, 790 women)Women given nutritional advice had a lower relative risk of having a preterm birth (two trials, 449 women) (risk ratio (RR) 0.46, 95% CI 0.21 to 0.98 ), head circumference at birth was increased in one trial (389 women) (mean difference (MD) 0.99 cm, 95% CI 0.43 to 1.55) and protein intake increased (three trials, 632 women) (protein intake: MD +6.99 g/day, 95% CI 3.02 to 10.97). No significant differences were observed on any other outcomes.Balanced energy and protein supplementation (11 trials, 5385 women)Risk of stillbirth was significantly reduced for women given balanced energy and protein supplementation (RR 0.62, 95% CI 0.40 to 0.98, five trials, 3408 women), mean birthweight was significantly increased (random-effects MD +40.96 g, 95% CI 4.66 to 77.26 , Tau(2)= 1744, I(2) = 44%, 11 trials, 5385 women). There was also a significant reduction in the risk of small-for-gestational age (RR 0.79, 95% CI 0.69 to 0.90, I(2) = 16%, seven trials, 4408 women). No significant effect was detected for preterm birth or neonatal death.High-protein supplementation (one trial, 1051 women)High-protein supplementation (one trial, 505 women), was associated with a significantly increased risk of small-for-gestational age babies (RR 1.58, 95% CI 1.03 to 2.41).Isocaloric protein supplementation (two trials, 184 women)Isocaloric protein supplementation (two trials,184 women) had no significant effect on birthweight and weekly gestational weight gain.

AUTHORS' CONCLUSIONS

This review provides encouraging evidence that antenatal nutritional advice with the aim of increasing energy and protein intake in the general obstetric population appears to be effective in reducing the risk of preterm birth, increasing head circumference at birth and increasing protein intake, there was no evidence of benefit or adverse effect for any other outcome reported.Balanced energy and protein supplementation seems to improve fetal growth, and may reduce the risk of stillbirth and infants born small-for-gestational age. High-protein supplementation does not seem to be beneficial and may be harmful to the fetus. Balanced-protein supplementation alone had no significant effects on perinatal outcomes.The results of this review should be interpreted with caution, the risk of bias was either unclear or high for at least one category examined in several of the included trials and the quality of the evidence was low for several important outcomes. Also the anthropometric characteristics of the general obstetric population is changing, therefore, those developing interventions aimed at altering energy and protein intake should ensure that only those women likely to benefit are included. Large, well designed randomised trials are needed to assess the effects of increasing energy and protein intake during pregnancy in women whose intake is below recommended levels.

Impaired fetal growth and arterial wall thickening: a randomized trial of ω-3 supplementation

OBJECTIVES

Impaired fetal growth is an independent cardiovascular risk factor and is associated with arterial wall thickening in children. No preventive strategy has been identified. We sought to determine whether dietary ω-3 fatty acid supplementation during early childhood prevents the association between impaired fetal growth and carotid arterial wall thickening.

METHODS

The Childhood Asthma Prevention Study was a randomized, controlled single-blind trial in 616 children born at term, recruited antenatally from maternity hospitals in Sydney. Participants were randomized to either a 500-mg-daily fish oil supplement and canola-based margarines and cooking oil (ω-3 group), or a 500-mg-daily sunflower oil supplement and ω-6 fatty acid-rich margarines and cooking oil (control group), from the start of bottle-feeding or 6 months of age until 5 years of age. Carotid intima-media thickness (IMT), a noninvasive measure of subclinical atherosclerosis, was the primary endpoint of a cardiovascular substudy (CardioCAPS) at age 8 years. We examined the association of fetal growth with carotid IMT in children with birth weight <90th percentile (ω-3 group [n = 187], control group [n = 176]).

RESULTS

In the control group, fetal growth was inversely associated with carotid IMT, but this was prevented in the ω-3 group (difference between groups of 0.041 mm [95% confidence interval 0.006, 0.075] per kg birth weight, adjusted for gestational age and gender, P(heterogeneity) = .02).

CONCLUSIONS

The inverse association of fetal growth with arterial wall thickness in childhood can be prevented by dietary ω-3 fatty acid supplementation over the first 5 years of life.