Iowa State professor aims to revolutionize stress studies

Elizabeth (Birdie) Shirtcliff, an associate professor in human development and family studies at Iowa State University, has developed a device that will make the measurement of the stress-related hormone cortisol easier and faster — and as a result, stress studies can be much more precise.

“We have the potential to better understand what makes a situation stressful in that moment,” Shirtcliff said.

Stress is recognized as a contributor to every single one of the top 10 causes of death in the United States, including heart disease — which sits at No. 1. People of all ages also suffer from chronic stress-related health problems that impact their well being every day of their lives.

Yet stress can be tough to gauge. Levels of the hormone cortisol are one of the best indicators of stress, but the standard way to measure cortisol — through a blood or saliva test — still requires shipping the sample off to a testing lab.

Cortisol fluctuates constantly as humans react to daily challenges — whether handling social interactions or taking an unexpected exam. By the time the results are in on such a slow test, the environment that was causing a person’s stress could have easily shifted, invalidating the tests.

“It can be days to weeks to months before you find out what the cortisol levels were,” Shirtcliff said. “We know cortisol can really influence people’s emotions and behaviors, but currently, we can only look back in time and see the relationship.”

But Shirtcliff’s device is about to change all that. It can read a person’s hormone levels in a matter of minutes.

“You’re not finding out five months from now that you were really stressed back in February — you’re finding out right there, right now, how you’re doing,” she said.

Shirtcliff came up with the device — called VerOFy — with the help of the development company Oasis Diagnostics. It’s a “spit stick” that looks and works a little like a pregnancy test. VerOFy is looking for hormones in saliva, so a person sucks on one end of the stick and waits for a strip at the other end of the stick to change color.

The amount of color change corresponds to a certain cortisol level in the saliva, indicating a certain stress level in the individual. The results can be determined in 20 minutes, right in front of a person’s eyes, and can be precisely measured on a portable reader.

Shirtcliff and her laboratory assistants at Iowa State are currently running extensive tests on the device, but she expects testing to be done by the end of the year. She said VerOFy will initially be used to perform better lab research on stress and its effects, but eventually people might use the devices at home, too.

“We’re pushing for measurement at the ‘point of care,’ so a person can get information at the time and place it’s most useful,” Shirtcliff said.

A plethora of new hormone research

Shirtcliff described VerOFy earlier this year in the scientific journal Clinical Therapeutics, one of a number of new papers being published out of her laboratory.

Her Iowa State graduate students also have eight articles coming out this month in a special issue of the journal Developmental Psychobiology. The articles discuss new research on the relationship between testosterone and cortisol, shedding light on the little known but critically important interactions between these hormones in adolescents.

“Scientists used to think, for the most part, that when one of the two hormones was active, the other shut off," said Andrew Dismukes, a graduate research assistant in Shirtcliff’s lab, who co-authored two of the articles. New research he and his colleagues conducted indicates that’s not always the case.

In one study, Dismukes analyzed hormone data for incarcerated youths and compared it to behavioral and life history information collected from interviews and questionnaires. He found that youths who had higher cortisol levels also had higher testosterone levels. And he found the positive relationship between the two hormones was stronger in youths who had worse early-life experiences.

“Hormones have these huge implications,” Dismukes said. “Cortisol and testosterone are uniquely related to behavioral outcomes.”

“Data like Dismukes’s can help researchers better understand and even predict mental health issues,” Shirtcliff said.

For example, the researchers found that glib, psychopathic, or manipulative youths were more likely to have a stronger positive relationship between testosterone and cortisol levels in their bodies. That means hormone studies like these are helping scientists understand some of the biology underlying why people are the way they are.

“There are some good reasons to be paying attention to saliva,” Shirtcliff said.