Baltimore A doctor says stress, family medical history or possibly even poison led to the death of Vladimir Lenin, debunking a popular theory that a sexually-transmitted disease debilitated the former Soviet Union leader.

UCLA neurologist Dr Harry Vinters and Russian historian Lev Lurie reviewed Lenin's records for an annual University of Maryland School of Medicine conference on famous people's deaths.

The 53-year-old leader suffered several strokes before dying in 1924 and what caused them isn't clear. An autopsy found blood vessels in his brain were extremely hardened, results that have been difficult to understand, said Dr Philip Mackowiak, who organises the yearly event.

"Number one, he's so young and number two, he has none of the important risk factors," he said. Lenin didn't smoke — he never let smokers near him. He didn't have diabetes, wasn't overweight and the autopsy didn't find evidence of high blood pressure.