Almost every cell in the human body is affected by IGF-I. IGF-I plays a major role in the regulation of metabolic/physiologic function across the lifespan. In addition to its effects on growth and development, IGF-I has been associated with numerous biological processes including cell cycle regulation, differentiation, proliferation, and apoptosis. Any perturbations during growth and development known to influence the IGF system (e.g., under-/over-nutrition, hyperinsulinemia, perturbed hormonal milieu) may manifest as "programmed" chronic disease risk factors. With the disparate prevalence in disease risk and life expectancy across racial/ethnic groups worldwide, understanding the mechanisms and role of the IGF axis and relative contribution to late disease onset is critical for establishing appropriate prevention and intervention strategies. Given the role of growth and development during childhood and adolescence on energy homeostasis, small changes in development of the IGF axis could have huge repercussions for racial/ethnic differences as well as a wide range of inherent physiological and metabolic functions that influence growth and development and their relationship with health. Metabolic perturbations are associated with changes throughout the IGF axis resulting in reductions of IGF-I activity. Further, inherent individual differences may interact with metabolic perturbations throughout the life course affecting the IGF axis resulting in racial/ethnic disparities in chronic disease outcomes. The extent of genetic heterogeneity among non-Europeans and, therefore, the frequency of etiological relevant genetic contributions may differ and may explain at least in part disparities in chronic disease outcomes. Because the effects of the IGF axis on growth and development represent both immediate and long-term health risk, as well as racial/ethnic disparities in health, strategies for handling health implications are urgently needed.