Stunted growth in children from fetal life to adolescence : Risk factors, consequences and entry points for prevention - Cohort studies in rural Bangladesh

Sammanfattning: Stunted growth affects one in four children under the age of five years and comes with great costs for the child and society. With an increased understanding of the long-term consequences of chronic undernutrition the reduction of stunted growth has become an important priority on the global health agenda. WHO has adopted a resolution to reduce stunting by 40% by the year 2025 and to reduce stunting is one of the targets under the Sustainable Development Goals.The aim of this thesis was to study linear growth trajectories, risk factors and consequences of stunting and recovery of stunting from fetal life to adolescence in a rural Bangladeshi setting and to assess the cost-effectiveness of a prenatal nutrition intervention for under-five survival and stunting.A birth cohort of children of women participating in the Maternal and Infant Nutrition Interventions trial (MINIMat), a randomized prenatal food and multiple micronutrient (MMS) trial, was followed from birth to adolescence. Information about socioeconomic and nutritional characteristics of the mother and father was collected, and frequent anthropometry assessments of the child were done at birth, in infancy, and during childhood and adolescence. At puberty, pubertal stages according to Tanner, age at menarche and start of the pubertal growth spurt in boys were assessed. Calculations were made regarding the cost-effectiveness of prenatal food and micronutrient intervention related to the disability adjusted life years (DALYs) lost by death and stunting.At birth, the children were on average short compared the WHO growth reference and more than half of the children were Small-for-Gestational-Age. Linear growth faltered dramatically up to 2 years, after which height-for-age Z-score increased up to adolescence. The prevalence of stunting was highest at 2 years (50%) and thereafter decreasing to 25% in adolescence. Birth size, maternal anthropometry and parental education were the most influential factors for linear growth up to and stunting at 2 years. Conditions after birth, such as feeding practices and morbidity, were less important. At 10 years, children born to short mothers (<147.5 cm), mothers with no education, or those conceived in the pre-monsoon season had an increased probability to be stunted. The median age at menarche was 13.0 years. Children that were stunted in infancy and childhood had later pubertal development as compared to non-stunted children. Children that recovered from stunting had a similar timing of puberty as their peers who had never been stunted. Supplementation with combined early prenatal food and multiple micronutrients was highly cost-effective in averting DALYs from under-five deaths and stunting.The results from this thesis support the conclusion that a lifecycle approach is needed for the prevention of stunting. The gaps between current knowledge, policy and practice needs to be closed, with more emphasis given to prenatal interventions.