By Nellie Peyton

DAKAR, Oct 24 (Thomson Reuters Foundation) - The first lady of Sierra Leone says she is a "hands-on woman" with a sure-fire strategy to tackle child marriage - she visits elders across the land and urges them to wield influence and prolong the nation's childhood.

"I'm a hands-on woman," Sia Nyama Koroma told the Thomson Reuters Foundation. "I go myself, leave my comfort zone, and travel the length and breadth of Sierra Leone with my team."

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Koroma has spearheaded efforts to eradicate child marriage in the region - West and Central Africa have among the world's highest rates - and was the first to propose a meeting of African leaders to share best practices.

The landmark gathering is the first of its kind in the region, with political, community and religious leaders from 27 countries meeting in Senegal this week.

Persuading religious and traditional leaders to use their influence in rural areas has been the most successful strategy in Sierra Leone, where child marriage rates have steadily fallen in the last ten years, said Koroma.

"Child marriage is a gross violation of women's rights, and we cannot be complacent," she told the Thomson Reuters Foundation. "Now is the time to act."

The first lady, who previously worked as a nurse and a chemist, said her tactic has been to meet personally with traditional chiefs and community elders - either in villages or at the presidential palace - and have them spread the word.

"They're very powerful. They're like presidents in the rural areas," said Koroma. "They act as change agents."

More than a third of girls in West and Central Africa marry under the age of 18, driven by poverty, insecurity and religious tradition. Though some of the countries prohibit child marriage, experts say the laws are rarely enforced.

Koroma said she went two routes to change minds, educating leaders about religious texts, specifically the fact that child marriage is not condoned in the Quran, and sharing data about the health risks of child-bearing for young girls.

Koroma said she encourages traditional chiefs to sign a memorandum of understanding when she visits their villages. The chiefs then make it known that parents will be fined if they try to marry off a child.

"When the chief says 'don't do this and don't do that', you will not do it," she said. "So that strategy has helped a lot."

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The rate of child marriage in Sierra Leone fell from 48 percent of girls married under 18 in 2008 to 39 percent in 2013, according to British charity Save the Children, though the rate is higher in poor and rural areas.

World leaders have pledged to end child marriage by 2030 under United Nations Sustainable Development Goals, but at current rates it will take more than 100 years to end it in West and Central Africa, said the U.N. children's agency (UNICEF).

(Reporting By Nellie Peyton; editing by Lyndsay Griffiths. Please credit Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, property rights, and climate change. Visit www.trust.org)

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