The long-range goal is to understand the behavioral and developmental effects of iron deficiency in infancy. Iron deficiency anemia affects one in 4-5 of the world's babies, and iron deficiency without anemia affects many more. The goal of the proposed 5-year project is to determine late functional consequences of early iron deficiency. This study continues to follow a well-maintained longitudinal cohort of 191 late adolescents/young adults in Costa Rica whose iron status and iron therapy were carefully documented in infancy. 87 percent of the original cohort is still participating. The project pursues our findings of major differences in school achievement and internalizing behavior problems at 10-13 years by assessing cognitive, motor, and emotional functioning at 19 years and the pursuit of higher education, job stability and level, mental health, early childbearing, etc. Late physical effects (delayed pubertal progression, obesity, stunting, cardiovascular risk factors) will be examined. Hypothesis-driven examination of specific cognitive functions will pursue earlier findings suggesting problems in spatial/working memory and selective attention/inhibition of the irrelevant. These functions are related to neural systems that have been shown to be altered in animal models of early iron deficiency. Sequential blood samples will again be obtained to extend earlier findings of stability in prolactin response from infancy to 12 years, relationships to behavior in early adolescence, and differing response depending on iron status in infancy. These assessments of specific cognitive functions and neuroendocrine responses to stress seek to identify the neural substrates underlying central nervous system effects of early iron deficiency. Beginning with longitudinal data already available from previous waves (infancy with 3 assessments, 5 years, 10-13 years, and 15-16 years), powerful statistical techniques such as hierarchical linear modeling and structural equation modeling will be used to identify patterns of continuity and change over time and to help clarify how biologic and environmental risks combine to result in poorer outcome.
