The Impact of Early-Life Growth on Long-Term Cardiometabolic and Neurocognitive Outcomes in High-Income Countries: A Neglected Public Health Problem.

Stunting affects approximately one-quarter of children worldwide. While the majority of these children live in Africa and Asia, a social gradient in height exists within high-income countries (HICs). In contrast to the coordinated focus on stunting in many low- and middle-income countries (LMICs), linear growth is not a public health priority in high-income settings. We reviewed the literature on relationships between linear growth and cardiometabolic outcomes (coronary heart disease [CHD], overweight/obesity, hypertension, and type 2 diabetes) and neurocognitive outcomes. We take a life-course approach, and use the "capacity load" model as a framework for understanding why stunting is associated with adverse cardiometabolic outcomes. We focus on the literature from HICs, but data from LMICs are included for context. Analysis of birth cohorts in high-, middle-, and low-income countries has consistently demonstrated relationships between early-life linear growth and downstream cardiometabolic and neurocognitive outcomes. These findings have been reinforced more recently by trial data. Birth size is associated with CHD, obesity, and type 2 diabetes, and with hypertension when small birth size is followed by accelerated postnatal growth. The patterns of postnatal linear growth associated with outcomes in adulthood are complex and context-dependent; both stunting and rapid linear growth in childhood are associated with cardiometabolic disease. We interpret these findings using the capacity-load model, a conceptual framework that describes the interactions between metabolic homeostatic capacity and metabolic load in shaping CHD risk. The strength and consistency of longitudinal associations between linear growth and several long-term deleterious outcomes across multiple settings and time points are striking. Future research should investigate both causal pathways and the potential for using height and growth velocity as markers for identifying children at increased risk of lifelong decrements in educational or cardiometabolic health outcomes who could benefit from early intervention.