The former president made this known in a book 'Against the Run of Play' written by Olusegun Adeniyi.
Obasanjo said that Yar'adua's response concerning he (Yaradua) state of health convinced him (Obasanjo) to go ahead with his decision.
Recall that in 2009, Yar'adua left for Saudi Arabia to receive treatment for pericarditis where he died on May 5, 2010.
Consequently, his vice president, Goodluck Jonathan became president.
In the book, Obasanjo was quoted to have said:
“One, the lingering doubts about his health, while the other was a very pervasive allegation that he had a manipulative wife who had too much influence on him,” Obasanjo said.
In response, Yar'adua was said to have dismissed the allegation against his wife.
He was said to have suggested that some people were just jealous of their closeness.
And on his health, he said Yar'adua handed him, (Obasanjo) the medical report he sought from him.
“Not being a medical practitioner, I gave the report to a friend and renowned professional in the medical field who reviewed it and told me that the person in the report was not on dialysis, which meant either he didn't have a kidney problem or that he had successfully undergone a kidney transplant. That was the report I had about his health,” Adeniyi quoted Obasanjo as saying.
Yar'adua was declared the winner of the presidential election held on April 21, 2007, and was sworn in on May 29, 2007.