Stevens Rose, Alvergne Alexandra, Vitzthum Virginia J
School of Anthropology and Museum Ethnography, The University of Oxford, Oxford, OX2 6PE, UK.
ISEM, Univ Montpellier, CNRS, IRD, Montpellier, France.
Evol Med Public Health. 2024 Sep 12;12(1):191-203. doi: 10.1093/emph/eoae022. eCollection 2024.
Female reproductive function flexibly responds to ecological variation in energy availability, but the roles of other ecologically limited resources, such as iron, remain poorly understood. This analysis investigates whether haemoglobin associates with investment in reproductive function in a rural natural fertility population living in the Bolivian .
We conducted a cross-sectional secondary analysis of prospectively collected biomarker and sociodemographic data, comprising 152 menstrual cycles from 96 non-contracepting women living at 3800 m altitude. Multivariable multilevel models were used to investigate (i) whether haemoglobin concentration is associated with ecological variation in subsistence strategy and seasonal conditions, and (ii) whether haemoglobin concentration is associated with the occurrence of ovulation and/or the concentration of luteal progesterone, two biomarkers of current investment in reproduction.
Haemoglobin concentrations were lower in arduous seasons among those women more dependent on traditional agropastoral subsistence strategies ( = -0.42, 95% CI: -0.80 to -0.04, = 0.032). During more arduous seasons, a 1 standard deviation increase in haemoglobin was associated with an over 3-fold increase in the odds of ovulation after adjusting for body fat, breastfeeding status, and age (adjusted odds ratio = 3.27, 95% CI: 1.10 to 9.27, = 0.033).
When conditions are relatively harsh and may be expected to improve, low haemoglobin levels are associated with lower current investment in reproduction and reduced fecundity. These results support the role of iron, independent of energy stores, as a limiting resource in modulating reproductive trade-offs.
女性生殖功能能灵活应对能量可利用性方面的生态变化，但其他受生态限制的资源（如铁）所起的作用仍知之甚少。本分析调查了在玻利维亚生活的农村自然生育人群中，血红蛋白是否与生殖功能投入相关。
我们对前瞻性收集的生物标志物和社会人口统计学数据进行了横断面二次分析，这些数据来自海拔3800米处96名未采取避孕措施的女性的152个月经周期。使用多变量多层次模型来研究：（i）血红蛋白浓度是否与生存策略和季节条件的生态变化相关；（ii）血红蛋白浓度是否与排卵的发生和/或黄体期孕酮浓度相关，这两个是当前生殖投入的生物标志物。
在更依赖传统农牧生存策略的女性中，艰苦季节的血红蛋白浓度较低（β = -0.42，95%置信区间：-0.80至-0.04，P = 0.032）。在更艰苦的季节，在调整了体脂、哺乳状况和年龄后，血红蛋白每增加1个标准差，排卵几率增加超过3倍（调整后的优势比 = 3.27，95%置信区间：1.10至9.27，P = 0.033）。
当条件相对恶劣且有望改善时，低血红蛋白水平与当前较低的生殖投入和生育力降低相关。这些结果支持了铁作为一种限制资源在调节生殖权衡中所起的作用，且独立于能量储备。
