This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Intellectual Merit: This proposal addresses a compelling contemporary question in human biology: How do development and energetics determine the pace and trajectory of reproductive maturation? This project takes advantage of a unique opportunity in The Gambia to directly address questions of early life factors in a human population where differences in maternal energetic status are known. Between 1989 and 1994, the Medical Research Council of the United Kingdom conducted a nutritional supplementation trial of pregnant women in the West Kiang District. Supplements were standardized for energy content, and supplementation status was cluster-randomized by village. The children born to participating mothers are now in their mid to late teenage years.
Subjects in this study will include 30 women born to mothers receiving supplements and 30 women born to controls. Measurements will include height, weight, body composition (measured by dual x-ray absorptiometry) ovarian hormone levels (measured in saliva), metabolic hormone levels (measured in blood and urine), and energy expenditure monitored by heart-rate telemetry and accelerometry. Measurements will be collected on three occasions at six month intervals. The central hypothesis is that women born to supplemented mothers will be less insulin sensitive to fluctuating energy availability as adolescents, will mature earlier, and will show less ovarian sensitivity to fluctuating energy availability.
Broader Impact: Most populations in the world show evidence of a shift over time toward earlier reproductive maturation with economic development. The mechanisms driving this change, however, are not yet clear, and suggestions that the trend may be continuing in the contemporary US have caused some alarm. Early maturation is linked to the risk of many chronic diseases such as diabetes and reproductive cancers. This project will illuminate how prenatal conditions influence the pace and trajectory of pubertal maturation. This project will provide research training for one female graduate student.
