"In June this year, I was told that there were signs of recurrence of my chronic condition called ulcerative colitis, and I did my best at work. while taking medicine," Abe told a press conference, reported Sputnik.
"But starting the middle of last month, my physical condition changed, and I felt very exhausted. Recurrence of the disease was confirmed at the beginning of this month," he added.
Abe said that he would step down because his worsened condition and treatment could threaten the decision-making process.
"In politics, getting results is the most important thing. Facing illness and treatment and being in poor physical form, I could not let myself make mistakes in important political decisions and fail to achieve results," he said further.
What about Shinzo Abe’s political career?
He previously served as Chief Cabinet Secretary from 2005 to 2006, and as Prime Minister from 2006 to 2007. He is the longest-serving Prime Minister in Japanese history. Abe has remained eight years in office and became Japan's longest-serving leader. The leader has beaten the record set by his great-uncle Eisaku Sato half a century ago, but his popularity has fallen to about 30 percent in recent opinion polls due to the handling of the coronavirus pandemic besides scandals among ruling party members.
The leader built his empire on the agenda of reviving the economy with his "Abenomics" policy of spending and monetary easing.
Abe also increased Japan's military spending to expand the role of its armed forces even as his ideology to run the country's pacifist constitution failed to make any impact.
Speculation that he would step down has been dismissed by allies in his ruling Liberal Democratic Party including Chief Cabinet Secretary Yoshihide Suga, who told Reuters on Wednesday that he meets Abe twice a day and has not seen any change in his health.