Modelling growth processes in Indian children and adolescents

Abstract

Human growth is a complex non-linear process that occurs in several stages, including the foetal, infancy, childhood, and adolescence phases. Different patterns of growth and underlying mechanisms characterise each of these stages. In this thesis, we examined various aspects of physiological growth in childhood and adolescence in the Indian population. Initially, we looked at two measures of growth that show high levels of adaptability: metabolism and body composition. We found that Indian children have significantly lower energy expenditure (at rest) compared to Western children, and we provide a potential explanation based on differences in organ mass and body composition. We further studied height growth during adolescence and characterised the pubertal growth spurt using serial measurements of height over eight years using the SITAR (SuperImposition by Translation and Rotation) model. Finally, we investigated the impact of a metabolic disorder, Type-1 Diabetes Mellitus (T1DM), on otherwise canalised height growth programming. We found that it leads to a delay and extension of the pubertal growth spurt, resulting in compromised height in children with T1DM. However, once the resulting SITAR model is parameterized by size, timing and intensity of pubertal growth, the underlying growth pattern in children with T1DM was indistinguishable from those without. Our study shows how the underlying growth mechanism is robust to a persisting metabolic insult. Our study adds to the knowledge for researchers, policymakers and clinicians to understand the optimal modes for personalised interventions to address the many non-communicable diseases, including the double burden of malnutrition, while considering the long-term health implications of growth.