Sarah Obama, President Barack Obama's grandma, injured after car rolls in Kogelo, Kenya

NAIROBI, Kenya — President Barack Obama's 91-year-old step-grandmother suffered bruises and shock after a car she was traveling in rolled over, a relative and a hospital official said Monday.

The relative said Sarah Obama was traveling to her home in the village of Kogelo, in western Kenya, when the accident happened Saturday night.

He said the vehicle lost control and rolled as the driver attempted to overtake a truck near the Kisumu airport. The relative asked not to be named because he is not authorized to speak for the family.

Najim Mawji, the chief operating officer of the Agha Khan hospital in Kisumu, said doctors discharged her Saturday night after she had gone through several tests.

Mawji said she coped well with the shock that came from the accident.

Sarah Obama is the second wife of Obama's paternal grandfather. Obama referred to her as "Granny" in his memoir, "Dreams from My Father," and described meeting her during his 1988 trip to his father's homeland and their awkwardness as they struggled to communicate.

Barack Obama has visited his Kenyan relatives three times in Kogelo, and his step-grandmother has gone to the U.S. at least three times. In a 2008 interview she said they are close, although they have to speak through an interpreter.

Kenya has a special regard for President Obama, the son of a Kenyan economist and an American anthropologist. Children, shops and dozens of minibuses — which carry names in Kenya — are named after the president.