Higher levels of physical victimization in women were linked to higher levels of cortisol in midday and less linear decline throughout the day, according to recent study findings published in Psychoneuroendocrinology.

“Existing studies have focused on the women’s [hypothalamic-pituitary-adrenal]-axis activity only,” Hyoun K. Kim, PhD, of the Oregon Social Learning Center and the department of psychology at the University of Oregon, said in a press release. “We indeed found that women’s, but not men’s, victimization was associated with multiple indicators of diurnal cortisol levels. It has been argued that interpersonal violence is more detrimental for women than for men, and our study suggests that it might indeed be due to disruptions in [hypothalamic-pituitary-adrenal]-axis activity.”

Kim and colleagues evaluated 122 couples to determine daily fluctuations of cortisol levels and interpersonal violence among them. Over four consecutive days, saliva samples were collected to measure cortisol samples four times a day — upon waking, 30 minutes later, middle to late afternoon and bedtime.

J. Josh Snodgrass

Higher levels of both men’s and women’s midday and evening cortisol values and lower cortisol values for women at 30 minutes after waking were all associated with higher levels of women’s intimate partner violence.

Cortisol levels 30 minutes after waking were significantly higher among both men and women compared with levels upon waking. Over the course of the day there was a nonlinear change or dampening of cortisol levels, linear decreases at midday and midday levels greater than zero among both men and women.

Compared to men who experienced low levels of intimate partner violence, men with higher levels had higher midday cortisol levels. However, there was no significant effect of intimate partner violence on 30-minute post-waking cortisol levels, midday levels or nonlinear changes in levels over the day.

Compared to women who reported lower levels of intimate partner violence, women with higher levels of violence had lower 30-minute post-waking cortisol levels, higher midday levels, less linear decline of levels at midday and less nonlinear dampening of levels throughout the day.

“We think we captured a good window on the subjects’ everyday rhythms,” study researcher J. Josh Snodgrass, PhD,also of the University of Oregon, said in the release. “There are fluctuations, such as may occur on a very bad day, but it’s minor and on the margins; they are easy to weed out when you have 4 days. It’s a high-quality sample. We think it’s the environmental and behavioral pieces that are influencing the cortisol rhythms.”