by Sheryl Stölberg

About the author: Sheryl Stölberg is the medical writer for the Los Angeles Times daily newspaper.

He wanted his wife to quit smoking.

It was a simple wish, yet its consequences were profound. This was in the 1970s, in Greece, where smoking was as cherished a pastime as baseball in America. Dimitrios Trichopoulos didn’t care about bucking the tide. He simply detested his wife’s addiction.

A young cancer epidemiologist at the University of Athens, Trichopoulos tried the usual guilt trip. He told her she was hurting herself. On this, he said, the medical literature was clear. When that didn’t work, he told her she was hurting him—an argument he could not support with statistics. She didn’t believe...