According to the World Development Report titled "Development and the next Generation", the rebels have focused on abducting males between 13 and 18 but people of all ages and both sexes have been taken.
The report quoted by the state-owned New Vision on Monday warned of the severe consequences of abduction and forced soldiering on youth.
"Two-thirds of them are severely beaten, a fifth are forced to kill and nearly 10 percent are forced to murder a family member or friend to bind them to the group," said the report.
"Those who had been abducted are more than three times as likely to have a serious physical injury or illness that impedes their ability to work. Abductees are twice as likely to report difficulties in family relations. They have nearly a year less education and they are twice as likely to be illiterate," it added.
This new figure is more than double the usual estimate. The United Nations Children's Fund has put the number of abducted children by the LRA at 25,000.
Save the Children in a press statement last week said 10,000 Ugandan children are still unaccounted for, while 1,500 are still believed to be held by the LRA.
The report came as the world marks the Day against the Use of Child Soldiers.
A total of 58 countries signed the "Paris Commitments" at a conference in France last week committing themselves to putting an end to the unlawful recruitment and use of children in armed conflicts.
They included 10 of the 12 nations where an estimated 250,000 children carry arms, namely Burundi, Chad, Colombia, Ivory Coast, the Democratic Republic of Congo, Nepal, Somalia, Sudan, Sri Lanka and Uganda.