Pope Francis had part of a lung removed "many, many years ago", the Vatican said Thursday after the 76-year-old's historic election, adding that he still enjoys good health.
"I confirm that many, many years ago he had an operation in which part of a lung was removed," Vatican spokesman Federico Lombardi told reporters.
"This is not a handicap in his life," Lombardi said. "Those who know him have always seen him in good health."
As a boy, Jorge Mario Bergaglio suffered from pneumonia and had part of his right lung removed in a painful operation from which it took him months to recover, according to Francesca Ambrogetti's 2010 biography of Francis, "El Jesuita" (The Jesuit).
"I remember the moment when, with a raging fever, I hugged my mother and said: 'Tell me what is happening!' She didn't know what to say, because the doctors were perplexed," then Buenos Aires archbishop Bergaglio said in the interviews.
When Francis was 22, he joined the Jesuit order and hoped to become a missionary but was turned down because of his health.
"I wanted to carry out missionary work in Japan, but because of the serious health problem I was dragging around with me, I was not allowed," he said.
Francis -- who walks with a slight limp -- is known at home for using public transport and riding a bicycle.
He is particularly reserved about his health, Ambroggeti said.
Francis said he realised the spiritual significance of pain when the nun who had prepared him for his first communion came to visit him in hospital after his lung operation.
"She said something which left a big impression on me and brought me great peace. She said: 'You are imitating Jesus'."
"Pain is not a virtue in itself, but the way we live with it can be virtuous. It makes us human" and helps us recognise Christ's humanity, he said.
According to Argentina's La Nacion daily, in 2007 Bergoglio suffered from an inflammation of the sciatic nerve that prevented him from travelling to Rome to take part in a consistory convened by his predecessor, Benedict XVI.