Growth and Body Composition in Breastfed Infants - Study on Age of Introduction of Complementary Foods in Iceland (IceAge2)

The purpose of this prospective cohort study is to investigate breast-milk and breastfeeding among infants who are exclusively and partially breastfed at 6 months of age in terms of characteristics that are hypothesised to contribute to growth and development of body composition in infancy.

The scientific originality lies in the simultaneous sampling of multiple factors that are believed to contribute to growth and development of body composition in infancy, i.e. energy content of breast-milk, metabolism-regulating hormones in breast-milk, infant temperament and appetite. The selection of two predefined study groups, i.e. infants exclusively breastfed until 6 months of age and infants given complementary foods in addition to breast-milk from 3-4 months of age, gives the opportunity to describe, and perhaps up to some point compare, what now is described by the World Health Organization and in official Icelandic infant recommendations as "optimal feeding" and what studies have suggested is "common feeding" in many countries. The methods are carefully chosen, i.e. appropriate and non-invasive isotopes and validated questionnaires are used. To our knowledge, no study has reported breast-milk composition in exclusively vs. partially breastfed infants.

Study Overview

• Status: Completed
• Conditions: Adiposity; Body Composition, Beneficial; Growth Acceleration
• Intervention / Treatment: Behavioral: Breastfeeding

Detailed Description

At approximately 5 months of age, all infants in Iceland are invited to receive routine care (health checkup, immunization etc.) at the well-baby clinics at the primary health care centers in their neighbourhood. Nurses at well-baby clinics in and around Reykjavik cooperating with the study investigators screen all infants for eligibility according the eligibility criteria. Mothers of eligible infants receive oral and written information about the study and if interested, a written consent is obtained and study investigators are informed about the potential participant.

When the infant is around 5.5 months of age, the mother is contacted and a home visit by study investigators scheduled. In the home visit, more detailed information about the study is given and equipment for predose urine samples are given. The date for the first part of the study (day 0) is scheduled.

Day -1 and/or day 0: Mothers sample predose urine sample(s): 2x4 ml for group "Exclusive Breastfeeding A" and 1x2 ml for groups "Exclusive Breastfeeding B" and "Partial Breastfeeding".

Day 0 (home visit by investigators): Infant weighed, drinks 2.5 g/kg body weight + 1 g doubly labeled water or 0.7 g deuterium.

Mothers sample postdose urine samples: 6x4 ml for group "Exclusive Breastfeeding A" (days 1, 2, 3, 5, 6, 7) and 2x2 ml for the other groups (days 0+5 hours and day 2).

Mothers of infants in groups "Exclusive Breastfeeding B" and "Partial Breastfeeding" keep a 3-day weighed food record assessing their infants' diet including breast milk (by test weighing).

Day 7 (home visit by investigators): 2x10 ml breast milk samples (fore and hind milk) are obtained, questionnaires answered by mothers: background questionnaire, food frequency questionnaire on mother's habitual diet, the Baby Eating Behaviour Questionnaire (BEBQ) and the Infant Behaviour Questionnaire-Revised (IBQ-R).

At 9 months of age mothers keep a 3-day weighed food record assessing the infants' diet including breast milk if the infant is still breastfed (by test weighing).

At 12 months of age the primary outcome measure is assessed. Day -1 or day 0: Mothers sample predose urine sample: 1x2 ml. Day 0 (home visit by investigators): Infant weighed, drinks 1.2 g deuterium. Mothers sample postdose urine samples: 2x2 ml (days 0+5 hours and day 2). Mothers keep a 3-day weighed food record assessing their infants' diet including breast milk if the infant is still breastfed (by test weighing).

Mothers answer the Child Eating Behaviour Questionnaire (CEBQ).

• Study Type: Observational
• Enrollment (Actual): 100

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 5 months to 6 months (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Infants receiving routine care at well-baby clinics at primary health care centers in and around Reykjavik, Iceland.

Description

Inclusion Criteria:

• Icelandic mother
• Singleton birth
• Gestational age 37-42 weeks
• Birth weight >2500 g
• Living in Iceland until 12 months of age
• Only groups "Exclusive Breastfeeding A" and "Exclusive Breastfeeding B": Exclusively breastfed at 5.5 months of age (≤5 formula feedings and ≤5 water feedings since birth allowed)
• Only group "Partial Breastfeeding": Receiving at least 100 g / 100 ml of complementary foods (formula or solids) at 5.5 months of age

Exclusion Criteria:

• Diseases or defects likely to affect growth or body composition
• Not breastfed at 5.5 months of age

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Exclusive Breastfeeding A; Mother/infant pairs with exclusive breastfeeding up to 6 months of age. Secondary outcome measure 2 (Metabolisable energy content of breast milk) measured in this group only.	Behavioral: Breastfeeding; Breastfeeding at 5.5 months of age (exclusive or partial)
Exclusive Breastfeeding B; Mother/infant pairs with exclusive breastfeeding up to 6 months of age.	Behavioral: Breastfeeding; Breastfeeding at 5.5 months of age (exclusive or partial)
Partial Breastfeeding; Mother/infant pairs with partial breastfeeding along with complementary foods at 6 months of age.	Behavioral: Breastfeeding; Breastfeeding at 5.5 months of age (exclusive or partial)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total body water measured by deuterium oxide	Total body water measured by deuterium oxide and used to determine fat-free mass	12 months of age of child

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Metabolisable energy content of breast milk measured using doubly labelled water	Measured using doubly labelled water (this outcome only measured in group labeled 'Exclusive Breastfeeding A')	5.5 months of age of child
Weight measured by infant scales	Weight measured by infant scales	0-12 months of age of child
Length measured by calibrated lengthboards	Length measured by calibrated lengthboards	0-12 months of age of child

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Infant eating behavior assessed using Baby Eating Behaviour Questionnaire (BEBQ)	Assessed using Baby Eating Behaviour Questionnaire (BEBQ)	5.5 months of age of child
Infant temperament assessed using the Infant Behaviour Questionnaire-Revised (IBQ-R)	Assessed using the Infant Behaviour Questionnaire-Revised (IBQ-R)	5.5 months of age of child
Leptin in breast milk	The metabolism-regulating hormone leptin measured in fore and hind milk samples	5.5 months of age of child
Ghrelin in breast milk	The metabolism-regulating hormone ghrelin measured in fore and hind milk samples	5.5 months of age of child
Cortisol in breast milk	The metabolism-regulating hormone cortisol measured in fore and hind milk samples	5.5 months of age of child
Infant eating behavior assessed using Child Eating Behaviour Questionnaire (CEBQ)	Assessed using Child Eating Behaviour Questionnaire (CEBQ)	12 months of age of child

Collaborators and Investigators

• Sponsor: University of Iceland
• Collaborators: Harvard Medical School (HMS and HSDM); Massachusetts General Hospital; University College, London
• Investigators: Principal Investigator: Geir Gunnlaugsson, PhD, School of Social Sciences, University of Iceland; Study Chair: Inga Thorsdottir, PhD, School of Health Sciences, University of Iceland

Publications and helpful links

General Publications

• Petersen E, Thorisdottir B, Thorsdottir I, Gunnlaugsson G, Arohonka P, Erlund I, Gunnarsdottir I. Iodine status of breastfed infants and their mothers' breast milk iodine concentration. Matern Child Nutr. 2020 Jul;16(3):e12993. doi: 10.1111/mcn.12993. Epub 2020 Mar 11.

Study record dates

Study Major Dates

• Study Start: December 1, 2014
• Primary Completion (Actual): October 1, 2019
• Study Completion (Actual): October 1, 2019

Study Registration Dates

• First Submitted: October 4, 2015
• First Submitted That Met QC Criteria: October 23, 2015
• First Posted (Estimate): October 26, 2015

Study Record Updates

• Last Update Posted (Actual): November 6, 2020
• Last Update Submitted That Met QC Criteria: November 5, 2020
• Last Verified: November 1, 2020

More Information

Terms related to this study

• Keywords: Body Composition; Breast Feeding; Growth; Infant; Milk, Human; Nutritional Sciences; Weaning
• Additional Relevant MeSH Terms: Overnutrition; Nutrition Disorders; Overweight; Body Weight; Obesity
• Other Study ID Numbers: IS-UI-IceAge2

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No