Adverse experiences in childhood are associated with altered hypothalamic–pituitary–adrenal (HPA) axis function and negative health outcomes throughout life. It is now commonly accepted that abuse and neglect can alter epigenetic regulation of HPA genes. Accumulated evidence suggests harsh parenting practices such as spanking are also strong predictors of negative health outcomes. We predicted harsh parenting at 2.5 years old would predict HPA gene DNA methylation similarly to abuse and neglect, and cortisol output at 8.5 years old. Saliva samples were collected three times a day across 3 days to estimate cortisol diurnal slopes. Methylation was quantified using the Illumina Infinium MethylationEPIC array BeadChip (850 K) with DNA collected from buccal cells. We used principal components analysis to compute a summary statistic for CpG sites across candidate genes. The first and second components were used as outcome variables in mixed linear regression analyses with harsh parenting as a predictor variable. We found harsh parenting significantly predicted methylation of several HPA axis genes, including novel gene associations with AVPRB1, CRHR1, CRHR2, and MC2R (FDR corrected p < 0.05). Further, we found NR3C1 methylation predicted a steeper diurnal cortisol slope. Our results extend the current literature by demonstrating harsh parenting may influence DNA methylation similarly to more extreme early life experiences such as abuse and neglect. Further, we show NR3C1 methylation is associated with diurnal HPA function. Elucidating the molecular consequences of harsh parenting on health can inform best parenting practices and provide potential treatment targets for common complex disorders.

童年时期的不良经历与下丘脑-垂体-肾上腺（HPA）轴功能的改变和一生的负面健康结果有关。现在人们普遍认为，滥用和忽视可以改变 HPA 基因的表观遗传调控。积累的证据表明，打屁股等严厉的养育方式也是负面健康结果的有力预测因素。我们预测，与虐待和忽视类似，2.5 岁时严厉的养育方式会预测 HPA 基因 DNA 甲基化，并预测 8.5 岁时皮质醇的输出。三天内每天收集三次唾液样本，以估计皮质醇的昼夜斜率。使用 Illumina Infinium MmethylationEPIC 阵列 BeadChip (850 K) 对从口腔细胞收集的 DNA 进行甲基化定量。我们使用主成分分析来计算候选基因中 CpG 位点的汇总统计数据。第一个和第二个组成部分用作混合线性回归分析中的结果变量，并以严厉的养育方式作为预测变量。我们发现严厉的养育显着预测了几个 HPA 轴基因的甲基化，包括与AVPRB1、CRHR1、CRHR2和MC2R 的新基因关联（FDR 校正p < 0.05）。此外，我们发现NR3C1甲基化预示着更陡的昼间皮质醇斜率。我们的研究结果扩展了现有文献，证明严厉的养育方式可能会影响 DNA 甲基化，类似于更极端的早期生活经历，如虐待和忽视。此外，我们发现NR3C1甲基化与昼夜 HPA 功能相关。阐明严厉的养育方式对健康的分子后果可以为最佳养育实践提供信息，并为常见的复杂疾病提供潜在的治疗目标。