FACTBOX: Key details on Nigeria's Umaru Yar'Adua

(Reuters) - Umaru Yar'Adua of Nigeria's ruling party was declared winner on Monday of a presidential poll rejected by the opposition and condemned by observers as a "charade".

Election monitors condemned the vote as "failed" because of widespread vote-rigging. Observers from the homegrown Transition Monitoring Group said it must be annulled and run again.

Here are some key facts on Umaru Yar'Adua:

* Umaru Yar'Adua has governed remote northern Katsina state since May 1999. A little-known figure in national politics, he emerged as President Olusegun Obasanjo's choice to be the ruling party's presidential candidate at the end of 2006.

* Yar'Adua's health has been the subject of media speculation. He has said he suffered illnesses since childhood but had since recovered. During a March 1 interview with Reuters he said he was satisfied with his health. His speech was interrupted by a persistent cough.

* Born in 1951, Yar'Adua comes from a famous political family. His father was a minister in the first government after independence and his older brother was No. 2 in Obasanjo's military regime in the late 1970s. Umaru Yar'Adua was a chemistry teacher until he went into business, then politics, in the 1980s.

* Yar'Adua's record as governor offers a mixed picture. He built new roads and added much-needed classrooms to many schools, but critics say his administration was disappointing in other key areas such as health and water supply.

* Katsina's budget grew during Yar'Adua's time, as did other state budgets, thanks to high oil prices. Yar'Adua's opponents, however, criticized how he spent the money. The most expensive project, a state government headquarters, cost $29 million with $17 million of that contracted to a company chaired by a cousin of Yar'Adua.