Fernald Lia C H, Gunnar Megan R
School of Public Health, University of California, Berkeley, Berkeley, CA 94720-7360, United States.
Soc Sci Med. 2009 Jun;68(12):2180-9. doi: 10.1016/j.socscimed.2009.03.032. Epub 2009 May 4.
Correlational studies have shown associations between social class and salivary cortisol suggestive of a causal link between childhood poverty and activity of the stress-sensitive hypothalamic-pituitary-adrenocortical (HPA) system. Using a quasi-experimental design, we evaluated the associations between a family's participation in a large-scale, conditional cash transfer program in Mexico (Oportunidades, formerly Progresa) during the child's early years of life and children's salivary cortisol (baseline and responsivity). We also examined whether maternal depressive symptoms moderated the effect of program participation. Low-income households (income <20th percentile nationally) from rural Mexico were enrolled in a large-scale poverty-alleviation program between 1998 and 1999. A comparison group of households from demographically similar communities was recruited in 2003. Following 3.5 years of participation in the Oportunidades program, three saliva samples were obtained from children aged 2-6 years from intervention and comparison households (n=1197). Maternal depressive symptoms were obtained using the Center for Epidemiologic Studies-Depression Scale (CES-D). Results were that children who had been in the Oportunidades program had lower salivary cortisol levels when compared with those who had not participated in the program, while controlling for a wide range of individual-, household- and community-level variables. Reactivity patterns of salivary cortisol did not differ between intervention and comparison children. Maternal depression moderated the association between Oportunidades program participation and baseline salivary cortisol in children. Specifically, there was a large and significant Oportunidades program effect of lowering cortisol in children of mothers with high depressive symptoms but not in children of mothers with low depressive symptomatology. These findings provide the strongest evidence to date that the economic circumstances of a family can influence a child's developing stress system and provide a mechanism through which poverty early in life could alter life-course risk for physical and mental health disorders.
相关性研究表明，社会阶层与唾液皮质醇之间存在关联，这表明儿童时期的贫困与应激敏感的下丘脑-垂体-肾上腺皮质（HPA）系统的活动之间存在因果联系。我们采用准实验设计，评估了家庭在孩子幼年时期参与墨西哥一项大规模有条件现金转移计划（机会计划，前身为进步计划）与孩子唾液皮质醇（基线和反应性）之间的关联。我们还研究了母亲的抑郁症状是否会调节计划参与的效果。1998年至1999年期间，来自墨西哥农村的低收入家庭（收入低于全国第20百分位数）参加了一项大规模扶贫计划。2003年招募了来自人口统计学上相似社区的家庭作为对照组。在参与机会计划3.5年后，从干预组和对照组家庭中2至6岁的儿童（n = 1197）获取了三份唾液样本。使用流行病学研究中心抑郁量表（CES-D）获取母亲的抑郁症状。结果显示，在控制了广泛的个人、家庭和社区层面变量后，参与机会计划的儿童唾液皮质醇水平低于未参与该计划的儿童。干预组和对照组儿童的唾液皮质醇反应模式没有差异。母亲的抑郁情绪调节了机会计划参与与儿童基线唾液皮质醇之间的关联。具体而言，对于抑郁症状严重的母亲所生的孩子，机会计划对降低皮质醇有很大且显著的效果，但对于抑郁症状较轻的母亲所生的孩子则没有这种效果。这些发现提供了迄今为止最有力的证据，证明家庭的经济状况可以影响儿童正在发育的应激系统，并提供了一种机制，通过这种机制，生命早期的贫困可能会改变身心健康障碍的人生历程风险。
