Nancy E. Adler, a health psychologist whose work helped transform the public understanding of the relationship between socioeconomic status and physical health, died on Jan. 4 at her home in San Francisco. She was 77.

The cause was pancreatic cancer, her husband, Arnold Milstein, said.

Dr. Adler was instrumental in documenting the powerful role that education, income and self-perceived status in society play in predicting health and longevity.

Today, the connection is well known — a truism among public health experts is that life expectancy is determined more by your ZIP code than your genetic code. But it was an obscure notion as recently as 30 years ago.

“It’s thanks to the decades of Nancy’s work and leadership that we now recognize socioeconomic status as one of the biggest and most consistent predictors of morbidity and mortality that we know of,” said Elissa Epel, a health psychologist at the University of California, San Francisco, and a mentee of Dr. Adler’s.

Beginning in 1997, Dr. Adler led the MacArthur Foundation Research Network on Socioeconomic Status and Health, a group of health economists, epidemiologists, physicians, public health experts, psychologists and sociologists that studied the relationship between socioeconomic status and health. The group has been credited with bringing into the mainstream the concept of social determinants of health, along with their implications for health and social policy.

“They looked at the question, ‘How does inequity or poverty or stress get under your skin?’” said Claire Brindis, a public health and policy researcher at U.C.S.F. “How does it affect your life? How many years are you going to live?”

Their work built on the Whitehall Study, a survey of British civil servants begun in 1967, which showed a strong link between social class and mortality. This finding pointed to factors beyond access to medical care or health insurance.

“What intrigued Nancy was that the relationship persisted even up into the upper echelons,” said Dr. Milstein, who is a prominent health policy researcher. “If you had one extra year of education, or you were making 200,000 pounds rather than 190,000 pounds, the relationship still existed.”

In 2000, Dr. Adler developed the MacArthur Ladder, a tool that asks people to mark their perceived income, education and socioeconomic status on the rungs of a 10-step ladder. It remains a reliable predictor of worsened health and early disease, indicating that self-perception of status is a meaningful marker in and of itself.

In a 2007 report for the MacArthur Foundation, she wrote, “Premature death is more than twice as likely for middle-income Americans as for those at the top of the income ladder, and more than three times as likely for those at the bottom than those at the top.”

Dr. Brindis said of Dr. Adler, “Once in a lifetime, along comes a scientist who changes how we see what’s right in front of us.”

Nancy Elinor Adler was born on July 26, 1946, in Manhattan to Alan and Pauline (Bloomgarden) Adler. Her mother was a teacher, her father a clothing manufacturer and salesman. When Nancy was a young child, her family moved west, settling in Denver.

In middle school, she was enraptured by Nancy Drew, the fictional teenage detective, who became a role model of sorts. “I think I really imprinted on Nancy Drew and got really excited about the idea of solving mysteries,” Dr. Adler said in a talk at U.C.S.F. in 2015.

She attended Wellesley College. In her sophomore year, she met Dr. Milstein, then a junior at nearby Harvard whose sister, Ann, also attended Wellesley.

“Ann invited me to meet a lovely girl from Denver living across the hall from her,” recalled Dr. Milstein, now a professor of medicine at Stanford University. “After she introduced us, my sister told me that this was the girl I would marry.”

Dr. Adler graduated in 1968 with a degree in psychology. She married Dr. Milstein in 1975.

In addition to her husband, she is survived by two daughters, Julia Adler-Milstein and Sarah Adler-Milstein; her brother, Richard Adler; and three grandchildren.

Dr. Adler’s research challenged prevailing thought early on. In graduate school at Harvard, where she earned a Ph.D. in 1973, she interviewed, for her doctoral dissertation, women before and after they had abortions.

“At the time, there was all this talk about how abortion was tantamount to lifelong trauma for the woman,” said Dr. Harvey Fineberg, who is president of the Gordon and Betty Moore Foundation, a philanthropy based in Palo Alto, Calif., and who was a longtime friend of Dr. Adler’s. “But Nancy found just the opposite. She found that women saw it as a chance to reposition their lives.”

In 1972, Dr. Adler was hired as an assistant professor of psychology at the University of California, Santa Cruz. She moved to the university’s San Francisco branch in 1977, where she became a professor of medical psychology and a vice chairwoman of the psychiatry and pediatrics departments. She retired in 2022.

At U.C.S.F., she embarked on a series of studies demonstrating the link between socioeconomic status and a spectrum of illnesses, such as diabetes and cardiovascular disease. In 1979, together with two colleagues there, she edited a book titled “Health Psychology,” thus coining the term. She started the first graduate and postdoctoral programs in health psychology in the United States in the 1980s. Similar programs have since sprung up across the globe.

A decade ago, buoyed by increasing attention to health disparities, Dr. Adler recommended to large hospitals that they build programs to measure and address the social factors of personal health. Today, hospitals and clinics routinely measure some of them, and many have programs aimed at mitigating them.