FELICIA C. MADIMENOS, then a student at University of Oregon, Eugene, Oregon, received funding in April 2009 to aid research on 'Lifestyle and Reproductive Effects on Bone Mineral Density in an Ecuadorian Forager-Horticulturalist Population,' supervised by Dr. James Josh Snodgrass. Bone mineral density (BMD) is the primary diagnostic parameter of bone health and a predictor of future fracture risk. The mechanisms and life history trade-offs affecting bone integrity evolved under conditions quite different from those experienced by industrialized populations, yet minimal data on bone health are available from non-Western, subsistence populations. Such data are particularly important because people in subsistence-based populations have dietary, reproductive, and activity patterns more like those of our evolutionary past. Using calcaneal ultrasound, this study presents the first available data on bone health among the Shuar, an indigenous Ecuadorian Amazonian population, and non-Shuar colonists (colonos) from the same area. Results show that among colonos, BMD is positively correlated with the consumption of fish and greens but not other food categories. Among Shuar, no such relationship is found but BMD is negatively associated with greater ownership of market goods. Further analyses considering the effects of reproductive history show that in both populations multiparity provides a protective effect on BMD but this protection is lost with increased duration of lactation per child (> 24 months). The most protective effect on bone health is realized when mothers breastfeed multiple children for shorter durations.