A version of this manuscript was presented at the 2011 Human Biology Association meeting and was awarded the E.E. Hunt Student Prize for Exceptional Student Presentation.
Reproductive effects on skeletal health in Shuar women of Amazonian Ecuador: A life history perspective†
Article first published online: 27 SEP 2012
Copyright © 2012 Wiley Periodicals, Inc.
American Journal of Human Biology
Volume 24, Issue 6, pages 841–852, November/December 2012
How to Cite
Madimenos, F. C., Snodgrass, J. J., Liebert, M. A., Cepon, T. J. and Sugiyama, L. S. (2012), Reproductive effects on skeletal health in Shuar women of Amazonian Ecuador: A life history perspective. Am. J. Hum. Biol., 24: 841–852. doi: 10.1002/ajhb.22329
- Issue published online: 15 OCT 2012
- Article first published online: 27 SEP 2012
- Manuscript Accepted: 29 AUG 2012
- Manuscript Revised: 7 AUG 2012
- Manuscript Received: 8 NOV 2011
- Wenner-Gren Foundation for Anthropological Research. Grant Number: 7970
- NSF. Grant Number: BCS-0925910
- Evonuk Foundation
- Leakey Foundation
- NIH. Grant Number: 5DP1OD000516-5 via UCSB Center for Evolutionary Psychology, University of Oregon
Clinical and epidemiological research suggest that bone mineral density (BMD) in women is shaped by various reproductive factors such as parity and lactation patterns. However, the extent of these effects on BMD remains unclear because of contradictory findings and a focus on industrialized populations. Because fertility patterns in these groups are vastly different than those of women from non-Western, subsistence populations, our current understanding of the reproductive effects on skeletal health is incomplete. Using a life history perspective, this study examines the relationship between reproductive factors and bone density among women from the Indigenous Shuar population, an Amazonian Ecuadorian forager-horticulturalist group.
This preliminary, cross-sectional study included 130 premenopausal and postmenopausal women (14–86 years old) from the Morona-Santiago region of Ecuador. Anthropometrics were recorded, as was estimated BMD using a calcaneal ultrasonometer. A reproductive history questionnaire was administered that included questions regarding menarche, parity, lactation patterns, and menopause.
Among postmenopausal women, early menarche and greater stature were significantly associated with higher bone density values. Among premenopausal women, few significant relationships between bone values and reproductive variables were documented; effects of lactation appeared to be transient and restored following weaning.
Although preliminary and not based on longitudinal data, these findings suggest that the effects of reproduction are transient as the system of calcium homeostasis in premenopausal women efficiently restores the bone loss that results from metabolically active reproductive states. Further, this research suggests that the timing of early life history events may canalize bone density phenotype. Am. J. Hum. Biol., 2012. © 2012 Wiley Periodicals, Inc.