Cortisol covariation within parents of young children: Moderation by relationship aggression. (December 2015)

• Record Type: Journal Article
• Authors: Saxbe, Darby E.; Adam, Emma K.; Schetter, Christine Dunkel; Guardino, Christine M.; Simon, Clarissa; McKinney, Chelsea O.; Shalowitz, Madeleine U.
• Is Part Of: Psychoneuroendocrinology. Volume 62(2015:Dec.)
• Page Start: 121
• Page End: 128
• Publication Date: 2015-12
• Subjects: HPA axis -- Cortisol -- Covariation -- Intimate partner aggression -- Pregnancy -- Moderation by relationship aggression; Psychoneuroendocrinology -- Periodicals; Endocrinology -- Periodicals; Neurology -- Periodicals; Psychiatry -- Periodicals; Neuropsychoendocrinologie -- Périodiques; 616.8
• DOI: 10.1016/j.psyneuen.2015.08.006
• Languages: English
• ISSNs: 0306-4530

Abstract

Highlights: Couples recruited after the birth of a child sampled their salivary cortisol on matched days during the subsequent two years. Couples' cortisol levels were strongly correlated with each other after sampling time and other covariates were controlled. Mother-reported relationship aggression was associated with stronger within-couple correlations in cortisol. Couples with higher aggression also had flattened diurnal cortisol slopes, a sign of poor adaptation to stress. Pregnant couples were included in the sample but pregnancy did not moderate couples' cortisol patterns or cortisol covariation. Abstract: Covariation in diurnal cortisol has been observed in several studies of cohabiting couples. In two such studies (Liu et al., 2013; Saxbe and Repetti, 2010), relationship distress was associated with stronger within-couple correlations, suggesting that couples' physiological linkage with each other may indicate problematic dyadic functioning. Although intimate partner aggression has been associated with dysregulation in women's diurnal cortisol, it has not yet been tested as a moderator of within-couple covariation. This study reports on a diverse sample of 122 parents who sampled salivary cortisol on matched days for two years following the birth of an infant. Partners showed strong positive cortisol covariation. In couples with higher levels of partner-perpetrated aggression reported by women at one year postpartum, both women and men had a flatter diurnal decrease in cortisol and stronger correlations with partners' cortisol sampled at the same timepoints. In other words, relationship aggression was linked both with indices of suboptimal cortisol rhythms in both members of the couples and with stronger within-couple covariation coefficients. These results persisted when relationship satisfaction and demographic covariates were included in the model. During some of the sampling days, some women were pregnant with a subsequent child, but pregnancy did not significantly moderate cortisol levels or within-couple covariation. The findings suggest that couples experiencing relationship aggression have both suboptimal neuroendocrine profiles and stronger covariation. Cortisol covariation is an understudied phenomenon with potential implications for couples' relationship functioning and physical health.