An early life observational cohort in China: Bone And MicroBiOme Onset (BAMBOO) study

Abstract Background: Early childhood growth and development is critical for long term health. Emerging science spotlights the significance of optimal gut microbiome and bone development during this period. The aim of the Bone And MicroBiOme Onset (BAMBOO) study is to determine age-appropriate trajectories for microbiome maturation and bone development, and to identify the influence of dietary factors in the process. This paper is to describe the rationale and study design, and reports study progress. Methods: BAMBOO is an ongoing prospective observational cohort study conducted in Tianjin, China. Children who meet the following requirements are invited to participate in this study: 1) full-term gestational birth (≥ 37 and ≤ 42 weeks); 2) singleton; and 3) signed informed consent by infant’s parents (or his/her legally accepted representative) and agree to fulfill the requirements of the study protocol. The exclusion criteria include pregnancy complication (such as pre-eclampsia, gestational diabetes), bowel disease, or currently participating or having participated in another clinical trial within 4 weeks prior to the start of this cohort. The study is composed of two groups of children: Group 1 includes children from birth to 12 months of age; group 2 includes children from 6 to 36 months of age. Questionnaires are used at different timepoints to collect information on infant feeding practice, medical history, concomitant medication, adverse events/serious adverse events and development benchmarks. Concurrent anthropometric measurements include length/height, weight, and bone measurements. Children’s dietary intake data are collected using 3-day-food diaries. Biological samples (stool, urine, and breastmilk) are also collected at different timepoints. Discussion: Recruitment of Bamboo started in September 2021 and is still ongoing. Data quality assessment and method validation have been conducted using early available samples. This study will provide unprecedented insights on early life microbiome maturation and bone development in Chinese infants and toddlers, and the impact of diet. The results may contribute to evidence-based policy making and inform nutrition healthcare programs for infants and toddlers aiming to benefit long-term health. Trial registration No.: ChiCTR2100049972 (August 16 th , 2021)