Data from: Natural selection in utero induced by mass layoffs: the hCG evidence

Evolutionary theory, when coupled with research from epidemiology, demography, and population endocrinology, suggests that contracting economies affect the fitness and health of human populations via natural selection in utero. We know, for example, that fetal death increases more among males than females when the economy unexpectedly contracts; that unexpected economic contraction predicts low secondary sex ratios; and that males from low sex ratio birth cohorts live, on average, longer than those from high sex ratio cohorts. We also know that low levels of human chorionic gonadotropin (i.e., hCG) measured in the serum of pregnant women predict fetal death. We do not, however, know whether male survivors of conception cohorts subjected to contracting economies exhibit, as theory predicts, higher hCG than those from other cohorts. We show, in 71 monthly conception cohorts including nearly two million California births, that they do. We thereby add to the literature suggesting that the economy, a phenomenon over which we collectively exercise at least some control, affects population health. Our findings imply that the effect arises via natural selection – a mechanism we largely ignore when attempting to explain, or alter, how collective choice affects our biology.将进化论与流行病学、人口学及种群内分泌学的研究相结合，可以得出推论：经济收缩会通过子宫内的自然选择过程影响人类种群的适合度与健康水平。举例而言，我们已知当经济意外下行时，男性胎儿的死亡率增幅高于女性；经济意外收缩可预测较低的次级性别比；且来自低次级性别比出生队列的男性，平均寿命高于来自高次级性别比出生队列的男性。我们还已知，孕妇血清中检测到的低水平人绒毛膜促性腺激素（human chorionic gonadotropin, hCG）可预测胎儿死亡风险。然而，我们尚不清楚，暴露于经济收缩环境的受孕队列中存活的男性，是否如理论预测的那样，体内hCG水平高于其他队列的男性。我们通过涵盖近200万例加州新生儿的71个月度受孕队列展开研究，证实了这一猜想。本研究由此为相关学术文献补充了新证据，表明经济这一我们至少可在一定程度上集体调控的现象，会对人群健康产生影响。我们的研究结果提示，该效应是通过自然选择这一机制实现的——而在尝试解释或改变集体选择如何影响我们的生物学状态时，我们大多忽略了这一机制。