Nigeria's president absent again, concerns increase for his health

Nigeria's President Muhammadu Buhari has been more absent this year than he has been present.

Two weeks ago, the 74-year-old left for London to have medical treatment for an unspecified condition and it's unclear when he will return.

In January, a planned 10-day vacation combined with "routine" check-ups, again in the U.K., stretched to nearly two months, fuelling speculation about the true state of his health.

Nigeria is Africa's most populous nation and just three years ago leapfrogged South Africa to become the continent's biggest economy.