A third study, begun about 30 years ago and still ongoing, looks at dietary factors besides salt, like animal protein, that contribute to high blood pressure.

“I remember there being criticism that he was an older man in his 70s, and could he complete the five years of the project,” Dr. Philip Greenland, a professor in Northwestern’s department of preventive medicine, said in an interview. “Then he had multiple renewals of the grant application, and at the last renewal he was 95 years old.”

Jeremiah Stamler was born on Oct. 27, 1919, in Brooklyn and grew up in West Orange, N.J. His parents — George Stamler, a dentist, and Rose (Baras) Stamler, a teacher — had immigrated from Russia.

After receiving a bachelor’s degree from Columbia University, he earned his medical degree from Long Island College of Medicine (now SUNY Downstate Health Sciences University) in Brooklyn in 1943 and was an intern at Kings County Hospital Center, also in Brooklyn. He served in the Army in Bermuda as a radiologist before beginning his career at Michael Reese Hospital in Chicago, where he worked with Dr. Louis Katz, a top cardiology researcher.

“Dr. Katz told me, ‘Why the hell do you want to go into research?’” Dr. Stamler told The Tribune. “‘You never win. When you first discover something, people will say, “I don’t believe it.” Then you do more research and verify it and they’ll say, “Yes, but. …” Then you do more research, verify it further, and they’ll say, “I knew it all the time.”’ And he was right.”

In the late 1950s, Dr. Stamler joined both the Chicago Board of Health and Northwestern, as a part-time assistant professor of medicine. In 1965, when he was director of the board’s heart disease control program, he was subpoenaed to testify by the House Committee on Un-American Activities. Accused of having been part of a Communist Party underground in the 1950s, he refused to testify or to take the Fifth Amendment, as many other witnesses did. Instead he gave a statement saying he was a loyal American.