Vissers et al. Systematic Reviews (2016) 5:149 DOI 10.1186/s13643-016-0324-3
PROTOCOL
Open Access
The timing of complementary feeding in preterm infants and the effect on overweight: study protocol for a systematic review Karin M. Vissers1, Edith J. M. Feskens2*, Johannes B. van Goudoever3 and Arieke J. Janse1
Abstract Background: In term infants, there is evidence that early complementary feeding is a risk factor for childhood obesity. Therefore, timely introduction of complementary feeding during infancy is necessary. The World Health Organization (WHO) and European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) both developed recommendations for the start of complementary feeding for term-born infants. However, these guidelines cannot be directly translated to preterm infants. Recent literature looking at the introduction of complementary feeding in preterm infants gives contrasting information. Given these contrasting reports on the introduction of solid foods in premature born infants, a systematic review is needed. The primary objective of this study is to analyze the effect of the time starting complementary feeding on overweight (including obesity) in preterm infants. Methods: An electronic systematic literature search with pre-defined terms will be conducted in Cochrane, PubMed, EMBASE, Web of Science, Scopus, and CINAHL. There will be no restriction for time period. Primarily, data from randomized controlled trials (RCTs) will be included in this systematic review. Search terms will include preterm infants, complementary feeding, overweight, and their synonyms. Article selection, including risk of bias assessment, will be performed by three reviewers independently. Body mass index standard deviation score (BMI-SDS or BMI-Z-score) will be used to compare studies. The consistency of results across the studies will influence the decision whether or not to combine results in a meta-analysis. Studies that cannot be included in the meta-analysis will be described in a narrative analysis. Discussion: This systematic review will give an overview of the existing knowledge on the timing of complementary feeding in preterm infants and the effect on overweight. It will form a basis for future guidelines for complementary feeding for preterm infants. Systematic review registration: PROSPERO CRD42015014215 Keywords: Preterm infants, Complementary feeding, Obesity, Overweight Abbreviations: AHRQ, Agency for Healthcare Research and Quality; BMI, Body mass index; BMI-SDS, Body mass index standard deviation score; ESPGHAN, European Society for Paediatric Gastroenterology Hepatology and Nutrition; PRISMA-P, Preferred Reporting Items for Systematic Reviewsand Meta-analyses Protocol; RCT, Randomized controlled trials; WHO, World Health Organization
* Correspondence: [email protected] 2 Division of Human Nutrition, Agrotechnology and Food Sciences Group, Wageningen University, Wageningen, The Netherlands Full list of author information is available at the end of the article © 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Vissers et al. Systematic Reviews (2016) 5:149
Background Complementary feeding is defined as the introduction of non-(breast)milk foods or nutritive liquids when milk alone is no longer sufficient to meet all nutritional requirements of infants. In this period, there is a gradual transition to eating family foods [1, 2]. Complementary feeding is associated with major changes in both macronutrient and micronutrient intake. Timely introduction of complementary feeding during infancy is necessary for both nutritional and developmental reasons [2]. In healthy term-born infants living in Europe, the recommendations for the age at which complementary feeding should be introduced are based on considerations on the optimal duration of exclusive breastfeeding. A World Health Organization (WHO)-commissioned systematic review concluded that there were no differences in growth between infants exclusively breast-fed for 3–4 months versus 6 months. Therefore, the WHO recommends mothers worldwide to exclusively breastfeed infants for the child’s first 6 months to achieve optimal growth, development, and health. Thereafter, they should be given nutritious complementary foods and continue breastfeeding up to the age of 2 years or beyond [3–5]. The European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) Committee recommended that the introduction of complementary feeding should not be before 17 weeks but should not be delayed beyond 26 weeks of age, acknowledging exclusive or full breastfeeding until 6 months as a desirable goal [6]. In term infants, early complementary feeding may be a risk factor for childhood obesity. A systematic review and meta-analyses of risk factors for childhood overweight identifiable during infancy by Weng et al. found some evidence supporting the early introduction of solid foods as a risk factor for later overweight [7]. However, a systematic review determining whether the timing of introducing solid foods is associated with obesity in infancy and childhood by Moorcroft et al. did not find a clear association between the timing of introducing solid foods and obesity in infancy and childhood [8]. Furthermore, Pearce et al. showed in a recent systematic review in 2013 about the timing of introduction of complementary feeding in term infants, and the risk of childhood obesity concluded that the timing of complementary foods has no clear association with childhood obesity, although very early introduction of solid foods (≤4 months of age) may result in an increase in childhood BMI [9]. These reviews and recommendations however concern healthy term-born infants, and results cannot be translated to preterm infants. Preterm infants are a heterogeneous population because their gestational age at birth could vary between 23 to 36 weeks. In the Netherlands, the incidence of preterm birth (
PROTOCOL
Open Access
The timing of complementary feeding in preterm infants and the effect on overweight: study protocol for a systematic review Karin M. Vissers1, Edith J. M. Feskens2*, Johannes B. van Goudoever3 and Arieke J. Janse1
Abstract Background: In term infants, there is evidence that early complementary feeding is a risk factor for childhood obesity. Therefore, timely introduction of complementary feeding during infancy is necessary. The World Health Organization (WHO) and European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) both developed recommendations for the start of complementary feeding for term-born infants. However, these guidelines cannot be directly translated to preterm infants. Recent literature looking at the introduction of complementary feeding in preterm infants gives contrasting information. Given these contrasting reports on the introduction of solid foods in premature born infants, a systematic review is needed. The primary objective of this study is to analyze the effect of the time starting complementary feeding on overweight (including obesity) in preterm infants. Methods: An electronic systematic literature search with pre-defined terms will be conducted in Cochrane, PubMed, EMBASE, Web of Science, Scopus, and CINAHL. There will be no restriction for time period. Primarily, data from randomized controlled trials (RCTs) will be included in this systematic review. Search terms will include preterm infants, complementary feeding, overweight, and their synonyms. Article selection, including risk of bias assessment, will be performed by three reviewers independently. Body mass index standard deviation score (BMI-SDS or BMI-Z-score) will be used to compare studies. The consistency of results across the studies will influence the decision whether or not to combine results in a meta-analysis. Studies that cannot be included in the meta-analysis will be described in a narrative analysis. Discussion: This systematic review will give an overview of the existing knowledge on the timing of complementary feeding in preterm infants and the effect on overweight. It will form a basis for future guidelines for complementary feeding for preterm infants. Systematic review registration: PROSPERO CRD42015014215 Keywords: Preterm infants, Complementary feeding, Obesity, Overweight Abbreviations: AHRQ, Agency for Healthcare Research and Quality; BMI, Body mass index; BMI-SDS, Body mass index standard deviation score; ESPGHAN, European Society for Paediatric Gastroenterology Hepatology and Nutrition; PRISMA-P, Preferred Reporting Items for Systematic Reviewsand Meta-analyses Protocol; RCT, Randomized controlled trials; WHO, World Health Organization
* Correspondence: [email protected] 2 Division of Human Nutrition, Agrotechnology and Food Sciences Group, Wageningen University, Wageningen, The Netherlands Full list of author information is available at the end of the article © 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Vissers et al. Systematic Reviews (2016) 5:149
Background Complementary feeding is defined as the introduction of non-(breast)milk foods or nutritive liquids when milk alone is no longer sufficient to meet all nutritional requirements of infants. In this period, there is a gradual transition to eating family foods [1, 2]. Complementary feeding is associated with major changes in both macronutrient and micronutrient intake. Timely introduction of complementary feeding during infancy is necessary for both nutritional and developmental reasons [2]. In healthy term-born infants living in Europe, the recommendations for the age at which complementary feeding should be introduced are based on considerations on the optimal duration of exclusive breastfeeding. A World Health Organization (WHO)-commissioned systematic review concluded that there were no differences in growth between infants exclusively breast-fed for 3–4 months versus 6 months. Therefore, the WHO recommends mothers worldwide to exclusively breastfeed infants for the child’s first 6 months to achieve optimal growth, development, and health. Thereafter, they should be given nutritious complementary foods and continue breastfeeding up to the age of 2 years or beyond [3–5]. The European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) Committee recommended that the introduction of complementary feeding should not be before 17 weeks but should not be delayed beyond 26 weeks of age, acknowledging exclusive or full breastfeeding until 6 months as a desirable goal [6]. In term infants, early complementary feeding may be a risk factor for childhood obesity. A systematic review and meta-analyses of risk factors for childhood overweight identifiable during infancy by Weng et al. found some evidence supporting the early introduction of solid foods as a risk factor for later overweight [7]. However, a systematic review determining whether the timing of introducing solid foods is associated with obesity in infancy and childhood by Moorcroft et al. did not find a clear association between the timing of introducing solid foods and obesity in infancy and childhood [8]. Furthermore, Pearce et al. showed in a recent systematic review in 2013 about the timing of introduction of complementary feeding in term infants, and the risk of childhood obesity concluded that the timing of complementary foods has no clear association with childhood obesity, although very early introduction of solid foods (≤4 months of age) may result in an increase in childhood BMI [9]. These reviews and recommendations however concern healthy term-born infants, and results cannot be translated to preterm infants. Preterm infants are a heterogeneous population because their gestational age at birth could vary between 23 to 36 weeks. In the Netherlands, the incidence of preterm birth (
