Growth and Body Composition in Breastfed Infants - Study on Age of Introduction of Complementary Foods in Iceland
Condition: Adiposity; Body Composition, Beneficial; Growth Acceleration
MeSH terms: Obesity
Study type: Observational

Summary: 
      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.
    

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).
    

Intervention name(s): Breastfeeding
Intervention type(s): Behavioral
Intervention description(s): Breastfeeding at 5.5 months of age (exclusive or partial)
Observational model: Cohort
Time perspective: Prospective
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.
      
Biospecimen description: 
      Urine samples will be obtained from all infants at 5.5 and 12 months of age. Breast milk
      samples will be obtained from all mothers when the child is 5.5 months of age.
    
Keywords: Body Composition; Breast Feeding; Growth; Infant; Milk, Human; Nutritional Sciences; Weaning