It has long been thought that milk enhances the growth of children, especially in height, yet there has been relatively little work on this topic and results are not consistent. Most of the studies on milk consumption, linear growth indices, and/or IGF-I measurements among children have used a cross-sectional or supplementation design, and has been conducted in European or U.S. populations with relatively high baseline levels of milk intake. Serum IGF-I levels are positively correlated with height among young children and adults, and studies from Pune have shown that children who are small at birth but who grow rapidly in early childhood (up to 7 yrs) have particularly high IGF-I levels. Serum IGF-I is also positively correlated with milk intake in both children and adults, and serum levels rise after milk consumption. IGF-I is part of the protein fraction of milk, but it is not clear if the rise in serum IGF-I is due to the IGF-I present in milk, or if IGF-I undergoes digestion, and milk consumption triggers endogenous production of IGF-I, which is a potent growth factor active in many tissues, including bone.
To evaluate the relationship between milk consumption and fetal/infant/toddler growth, analysis of the dietary antecedents of growth along with current growth indices at 5-7 y of age
Methodology and Design
In the IAEA-B12 study we have investigated maternal plasma folate, vitamin B12 status, total homocysteine (tHcy) at 18, 28 and 34 weeks gestation and cord blood concentrations of plasma folate, vitamin B12 and tHcy in relation to offspring size at birth in 234 pregnant women (rural, urban) who delivered at King Edward Memorial Hospital (KEM) and Vadu hospital (an outreach rural hospital of KEM) in Pune. These babies were then followed up at 3, 6 months, 1y and 2y to test whether low maternal vitamin B12 status in Indian mothers and later in the child predisposes the offspring to adiposity and neuro-developmental delay.
This study will utilize the previously collected data to test hypotheses about the relationship of milk intake (during pregnancy or early childhood) and infant growth (assessed by anthropometric measures taken at birth and at 3, 6, 12, and 24 months). The cohort provides an ideal context in which to evaluate the relationship between milk consumption and fetal/infant/toddler growth, as its cohort design allows for analysis of the dietary antecedents of growth along with current growth indices at 6y. It also allows for control of confounding variables such as socioeconomic status, residence (urban/rural), maternal and paternal body size, and breastfeeding patterns.
These children are now being followed for at 5-7y of their age to assess the child’s regular diet and milk consumption (through food frequency and 24 hr recall), growth and body composition by anthropometry (height, weight, circumferences, skinfolds) and DXA. A random blood sample is collected to measure IGF-I levels. These data will generate a more complete, longitudinal picture of diet, IGF-I levels, and growth trajectory over the course of early childhood. We will collect data twice at a 6 month interval, to attain a more finely-grained view of changes in diet, growth and IGF-I. We will also interview mothers at the second visit on their emic (i.e. cultural) understandings of the relationship between milk consumption (cow, water buffalo, goat) and the growth and health of children to develop a better ethnographic sense of the associations between milk and growth in this population.
The IRB approval and financial support was obtained in April 2010.
Training of staff and standardisation of various techniques was completed in April 2010. The children are being followed at 5-7y of their age for their milk consumption history and growth and body composition by anthropometry and DXA. A random blood sample is collected for IGF-1 analysis. These children are being followed up at 6 months after their baseline visit for IGF-1 concentrations and milk consumption history.
Data collection started in May 2010 and baseline data collection is still ongoing. Uptill 12th Nov 2011 baseline data has been collected on 159 children and 6 month follow-up visit has been completed in 109 children.
Data entry is being done simultenously.
Preliminary analysis of these children at baseline showed the following:
|Body mass index - BMI (kg/m2)
|Waist-hip ratio (WHR)
|Mid arm circumference (cm)
|Sum of four skin folds (mm)
Values are median (25th -75th centiles)