New funding for MIDUS study researching pathways to health and illness across midlife

The Midlife in the U.S. (MIDUS) study examines how a variety of factors contribute to differences in physical and mental health and illness as individuals journey across midlife.

When Dr. Carol Ryff and other researchers first conceived of the study, they were unsure whether the scientific community would be interested in working with the multidisciplinary data they wanted to collect. Since MIDUS completed its first national survey in 1995, however, nearly 1,800 publications have been generated by the thousands of users of this public dataset.

Professor Carol Ryff

MIDUS has linked psychological, social, and behavioral factors to health outcomes through biological and neurological assessments. Ryff, a psychology professor and director of the UW-Madison Institute on Aging, became director of the MIDUS study in 2002. The National Institute on Aging, part of the National Institutes of Health, recently extended federal funding of MIDUS, providing $62 million to support the study’s next six years of research.

MIDUS has investigated various psychological factors, like well-being, personality, and sense of control, in the health of a national sample of Americans as they age. The study also examines social factors, life challenges, sociodemographic factors, health behaviors, and neurobiological factors.

“We had a major commitment at the get-go to bring a lot of psychological content into a national study of Americans, which had never happened before,” Ryff says.

At the outset, MIDUS was the first national longitudinal study in the U.S. following participants across the middle years of adult life. MIDUS has since collected data from more than 11,000 U.S. adults ranging from ages 25-74 when they first joined the study.

“This long expanse in the middle [of life] really hadn’t been systematically studied, so we went after what is happening in these middle years, which are a profoundly important time in life,” Ryff says. “That’s when people are in high gear in terms of family life, work life, citizenship, and roles in their communities.”

MIDUS studies the factors that contribute to illness and disease, but it also investigates the protective factors that keep people healthy when they experience adversity.

“Health research in this country has historically been focused on pathways into illness, disease, and death, and we are committed to learning about factors that protect against these outcomes,” Ryff says.

Ryff’s focus in MIDUS is on aspects of psychological well-being, such as purpose in life, which involves having meaningful goals and feelings that life is worth living. Extensive science now documents that having a high sense of purpose in life comes with the benefit of living longer.

MIDUS researchers are beginning to learn how purpose in life is linked to better health and extended longevity through biological mechanisms (stress hormones, inflammatory markers, cardiovascular risk factors) as well as neuroimaging studies of the brain. One MIDUS study showed activation of reward centers in the brain in response to positive images among participants with higher levels of well-being, including purpose in life, compared to participants with lower reported well-being. This longer reward center activation was also associated with lower levels of cortisol across the day. Cortisol is a stress hormone that at high levels has been linked to various physical health problems.

“What we know from multiple studies, but MIDUS has been really rich with these findings, is that purpose in life predicts longer lives and it predicts reduced biological risk factors,” Ryff says.

MIDUS’ research has taken a focused look at health inequalities, including racial health disparities. In a study including a sample of Black Americans from across Milwaukee, participants wore a movement-sensitive watch to collect data on sleep – how long they slept and the extent to which their sleep was interrupted. Findings showed Black adults got about 40 fewer minutes of sleep a night and had 10% lower sleep efficiency compared to White adults. These racial differences in sleep also predicted racial disparities in biomarkers that measure the risk for cardiometabolic diseases like heart disease and diabetes. The sleep measures were also linked to census data providing information about the neighborhoods in which participants live. This included indicators like education and income levels as well as crime rates. Neighborhood disadvantage further predicted poorer sleep among Black compared to White participants.

Researchers from across disciplines at UW-Madison are involved with the MIDUS study, including from the School of Social Work and School of Medicine and Public Health. Graduate students from the Psychology Department have co-authored 70 publications using MIDUS data, and more than 26,000 researchers around the world are using the publicly available dataset.

Over the next six years, MIDUS will investigate the impacts of the COVID-19 pandemic using nearly 30 years of prior information on some participants.

“We can tell very rich stories about impacts of the pandemic based on participants’ previous degrees of vulnerability or privilege,” Ryff says.

MIDUS will also study Alzheimer’s and dementia as many participants in the core sample are now in their 70s, 80s, and 90s.

“[These participants] give us incredible opportunities to study profiles of resilience as well as sad tales of vulnerability,” Ryff says. “Over the next six years of data collection, we will be assembling more information about pathways into Alzheimer’s and dementia as well as the factors that predict or protect against these frightening outcomes.”

Written by Sara Stanislawski