Dietary patterns before and during pregnancy and maternal outcomes: a systematic review.

BACKGROUND: Hypertensive disorders of pregnancy (HDP) and gestational diabetes mellitus (GDM) are common maternal complications during pregnancy, with short- and long-term sequelae for both mothers and children. OBJECTIVE: Two systematic review questions were used to examine the relation between 1) dietary patterns before and during pregnancy, 2) HDP, and 3) GDM. METHODS: A search was conducted from January 1980 to January 2017 in 9 databases including PubMed, Embase, and Cochrane. Two analysts independently screened articles using a priori inclusion and exclusion criteria; data were extracted from included articles, and risk of bias was assessed. After qualitative synthesis, a conclusion statement was drafted for each question and the evidence supporting the conclusion was graded. RESULTS: Of the 9103 studies identified, 8 [representing 4 cohorts and 1 randomized controlled trial (RCT)] were included for HDP and 11 (representing 6 cohorts and 1 RCT) for GDM. Limited evidence in healthy Caucasian women with access to health care suggests dietary patterns before and during pregnancy that are higher in vegetables, fruits, whole grains, nuts, legumes, fish, and vegetable oils and lower in meat and refined grains are associated with reduced risk of HDP, including preeclampsia and gestational hypertension. Limited but consistent evidence suggests certain dietary patterns before pregnancy are associated with reduced risk of GDM. These protective dietary patterns are higher in vegetables, fruits, whole grains, nuts, legumes, and fish and lower in red and processed meats. Most of the research was conducted in healthy, Caucasian women with access to health care. Insufficient evidence exists on the associations between dietary patterns before and during pregnancy and risk of HDP in minority women and those of lower socioeconomic status, and dietary patterns during pregnancy and risk of GDM. CONCLUSIONS: Although some conclusions were drawn from these systematic reviews, more research is needed to address gaps and limitations in the evidence.

Infant milk-feeding practices and childhood leukemia: a systematic review.

BACKGROUND: During the Pregnancy and Birth to 24 Months Project, the US Departments of Agriculture and Health and Human Services initiated a review of evidence on diet and health in these populations. OBJECTIVES: The aim of these systematic reviews was to examine the relation of 1) never versus ever feeding human milk, 2) shorter versus longer durations of any human milk feeding, 3) shorter versus longer durations of exclusive human milk feeding, and 4) feeding a lower versus higher intensity of human milk to mixed-fed infants with acute childhood leukemia, generally, and acute lymphoblastic leukemia, specifically. METHODS: The Nutrition Evidence Systematic Review team conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published January 1980 to March 2016, dual-screened the results using predetermined criteria, extracted data from and assessed risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence. RESULTS: We included 24 articles from case-control or retrospective studies. Limited evidence suggests that never feeding human milk versus 1) ever feeding human milk and 2) feeding human milk for durations ≥6 mo are associated with a slightly higher risk of acute childhood leukemia, whereas evidence comparing never feeding human milk with feeding human milk for durations <6 mo is mixed. Limited evidence suggests that, among infants fed human milk, a shorter versus longer duration of human milk feeding is associated with a slightly higher risk of acute childhood leukemia. None of the included articles examined exclusive human milk feeding or the intensity of human milk fed to mixed-fed infants. CONCLUSIONS: Feeding human milk for short durations or not at all may be associated with slightly higher acute childhood leukemia risk. The evidence could be strengthened with access to broadly generalizable prospective samples; therefore, we recommend linking surveillance systems that collect infant feeding and childhood cancer data.

Dietary patterns before and during pregnancy and birth outcomes: a systematic review.

BACKGROUND: Maternal diet before and during pregnancy could influence fetal growth and birth outcomes. OBJECTIVE: Two systematic reviews aimed to assess the relationships between dietary patterns before and during pregnancy and 1) gestational age at birth and 2) gestational age- and sex-specific birth weight. METHODS: Literature was searched from January, 1980 to January, 2017 in 9 databases including PubMed, Embase, and Cochrane. Two analysts independently screened articles using predetermined inclusion and exclusion criteria. Data were extracted from included articles and risk of bias was assessed. Data were synthesized qualitatively, a conclusion statement was drafted for each question, and evidence supporting each conclusion was graded. RESULTS: Of the 9103 studies identified, 11 [representing 7 cohorts and 1 randomized controlled trial (RCT)] were included for gestational age and 21 (representing 19 cohorts and 2 RCTs) were included for birth weight. Limited but consistent evidence suggests that certain dietary patterns during pregnancy are associated with a lower risk of preterm birth and spontaneous preterm birth. These protective dietary patterns are higher in vegetables; fruits; whole grains; nuts, legumes, and seeds; and seafood (preterm birth, only), and lower in red and processed meats, and fried foods. Most of the research was conducted in healthy Caucasian women with access to health care. No conclusion can be drawn on the association between dietary patterns during pregnancy and birth weight outcomes. Although research is available, the ability to draw a conclusion is restricted by inconsistency in study findings, inadequate adjustment of birth weight for gestational age and sex, and variation in study design, dietary assessment methodology, and adjustment for key confounding factors. Insufficient evidence exists regarding dietary patterns before pregnancy for both outcomes. CONCLUSIONS: Maternal dietary patterns may be associated with a lower preterm and spontaneous preterm birth risk. The association is unclear for birth weight outcomes.

Infant milk-feeding practices and cardiovascular disease outcomes in offspring: a systematic review.

BACKGROUND: During the Pregnancy and Birth to 24 Months Project, the US Departments of Agriculture and Health and Human Services initiated a review of evidence on diet and health in these populations. OBJECTIVES: The aim of these systematic reviews was to examine the relation of 1) never versus ever feeding human milk, 2) shorter versus longer durations of any human milk feeding, 3) shorter versus longer durations of exclusive human milk feeding, and 4) lower versus higher intensities of human milk fed to mixed-fed infants with intermediate and endpoint cardiovascular disease (CVD) outcomes in offspring. METHODS: The Nutrition Evidence Systematic Review team conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published January 1980-March 2016, dual-screened the results using predetermined criteria, extracted data from and assessed the risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence. RESULTS: The 4 systematic reviews included 13, 24, 6, and 0 articles, respectively. The evidence was insufficient to draw conclusions about endpoint CVD outcomes across all 4 systematic reviews. Limited evidence suggests that never versus ever being fed human milk is associated with higher blood pressure within a normal range at 6-7 y of age. Moderate evidence suggests there is no association between the duration of any human milk feeding and childhood blood pressure. Limited evidence suggests there is no association between the duration of exclusive human milk feeding and blood pressure or metabolic syndrome in childhood. Additional evidence about intermediate outcomes for the 4 systematic reviews was scant or inconclusive. CONCLUSIONS: There is insufficient evidence to draw conclusions about the relationships between infant milk-feeding practices and endpoint CVD outcomes; however, some evidence suggests that feeding less or no human milk is not associated with childhood hypertension.

Infant milk-feeding practices and food allergies, allergic rhinitis, atopic dermatitis, and asthma throughout the life span: a systematic review.

BACKGROUND: During the Pregnancy and Birth to 24 Months Project, the USDA and Department of Health and Human Services initiated a review of evidence on diet and health in these populations. OBJECTIVES: The aim of these systematic reviews was to examine the relation of 1) never versus ever feeding human milk, 2) shorter versus longer durations of any human milk feeding, 3) shorter versus longer durations of exclusive human milk feeding prior to infant formula introduction, 4) feeding a lower versus higher intensity of human milk to mixed-fed infants, and 5) feeding a higher intensity of human milk by bottle versus breast with food allergies, allergic rhinitis, atopic dermatitis, and asthma. METHODS: The Nutrition Evidence Systematic Review team conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published between January 1980 and March 2016, dual-screened the results according to predetermined criteria, extracted data from and assessed the risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence. RESULTS: The systematic reviews numbered 1-5 above included 44, 35, 1, 0, and 0 articles, respectively. Moderate, mostly observational, evidence suggests that 1) never versus ever being fed human milk is associated with higher risk of childhood asthma, and 2) among children and adolescents who were fed human milk as infants, shorter versus longer durations of any human milk feeding are associated with higher risk of asthma. Limited evidence does not suggest associations between 1) never versus ever being fed human milk and atopic dermatitis in childhood or 2) the duration of any human milk feeding and allergic rhinitis and atopic dermatitis in childhood. CONCLUSIONS: Moderate evidence suggests that feeding human milk for short durations or not at all is associated with higher childhood asthma risk. Evidence on food allergies, allergic rhinitis, and atopic dermatitis is limited.

Infant milk-feeding practices and diagnosed celiac disease and inflammatory bowel disease in offspring: a systematic review.

BACKGROUND: During the Pregnancy and Birth to 24 Months Project, the USDA and US Department of Health and Human Services initiated an evidence review on diet and health in these populations. OBJECTIVE: The aim of these systematic reviews was to examine the relationships of never versus ever feeding human milk, shorter versus longer durations of any and exclusive human milk feeding, and feeding a lower versus a higher intensity of human milk to mixed-fed infants with diagnosed celiac disease and inflammatory bowel disease (IBD). METHODS: The Nutrition Evidence Systematic Review team (formerly called the Nutrition Evidence Library) conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published January, 1980 to March, 2016, dual-screened the results using predetermined criteria, extracted data from and assessed risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence. RESULTS: We included 9 celiac disease and 17 IBD articles. Limited case-control evidence suggests never versus ever being fed human milk is associated with higher risk of celiac disease, but concerns about reverse causality precluded a conclusion about the relationship of shorter versus longer durations of any human milk feeding with celiac disease. Evidence examining never versus ever feeding human milk and IBD was inconclusive, and limited, but consistent, case-control evidence suggests that, among infants fed human milk, shorter versus longer durations of any human milk feeding are associated with higher risk of IBD. For both outcomes, evidence examining the duration of exclusive human milk feeding was scant and no articles examined the intensity of human milk fed to mixed-fed infants. CONCLUSION: Limited case-control evidence suggests that feeding human milk for short durations or not at all associates with higher risk of diagnosed IBD and celiac disease, respectively. The small number of studies and concern about reverse causality and recall bias prevent stronger conclusions.

Infant milk-feeding practices and diabetes outcomes in offspring: a systematic review.

BACKGROUND: During the Pregnancy and Birth to 24 Months Project, the US Departments of Agriculture and Health and Human Services initiated a review of evidence on diet and health in these populations. OBJECTIVES: The aim of these systematic reviews was to examine the relation of 1) never versus ever feeding human milk, 2) shorter versus longer durations of any human milk feeding, 3) shorter versus longer durations of exclusive human milk feeding, and 4) feeding a lower versus higher intensity of human milk to mixed-fed infants with type 1 and type 2 diabetes in offspring. METHODS: The Nutrition Evidence Systematic Review team conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published January 1980-March 2016, dual-screened the results according to predetermined criteria, extracted data from and assessed the risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence. RESULTS: The 4 systematic reviews included 21, 37, 18, and 1 articles, respectively. Observational evidence suggests that never versus ever feeding human milk (limited evidence) and shorter versus longer durations of any (moderate evidence) and exclusive (limited evidence) human milk feeding are associated with higher type 1 diabetes risk. Insufficient evidence examined type 2 diabetes. Limited evidence suggests that the durations of any and exclusive human milk feeding are not associated with intermediate outcomes (e.g., fasting glucose, insulin resistance) during childhood. CONCLUSIONS: Limited to moderate evidence suggests that feeding less or no human milk is associated with higher risk of type 1 diabetes in offspring. Limited evidence suggests no associations between the durations of any and exclusive human milk feeding and intermediate diabetes outcomes in children. Additional research is needed on infant milk-feeding practices and type 2 diabetes and intermediate outcomes in US populations, which may have distinct metabolic risk.

Systematic review methods for the Pregnancy and Birth to 24 Months Project.

The USDA's Nutrition Evidence Systematic Review (NESR) team specializes in conducting systematic reviews (SRs) to inform federal nutrition policy and programs. The NESR's dedicated staff collaborate with leading scientists to answer important food- and nutrition-related public health questions by objectively reviewing, evaluating, and synthesizing research using state-of-the-art methodology. NESR uses a rigorous, protocol-driven methodology that is designed to minimize bias; to ensure availability of SRs that are relevant, timely, and high quality; and to ensure transparency and reproducibility of findings. This article describes the methods used by NESR to conduct a series of SRs on diet and health in infants, toddlers, and women who are pregnant as part of the Pregnancy and Birth to 24 Months Project.