The study, which was published in the Journal of the American Medical Association, focused on India, Nepal, Pakistan and Bangladesh. For girls under 14, child marriage has dropped considerably in recent years. The practice fell by 35 percent in India, 45 percent in Bangladesh, 57 percent in Nepal and 61 percent in Pakistan.
But for girls over 16, it appears nothing has changed. This is despite the fact that in Bangladesh, India and Nepal, marriage before 18 is illegal.
The study findings were most discouraging for Bangladesh, where child marriages for girls aged 16 and 17 actually increased by 36 percent since 1991.
Our findings are heartening in terms of eliminating the practice among very young girls, but not among older girls, said study co-author Anita Raj in a press release from the University of California, San Diego, where she is a professor of medicine.
There needs to be a greater focus on prevention of marriage among later adolescents, said Raj. If we cannot impact [the] reduction of marriage in this age group, we'll continue to see inadequate change on reduction of girl child marriage as a whole.
UNICEF defines child marriage as a formal marriage or informal union before age 18. Both boys and girls can be married off as minors, but girls are disproportionately affected.
Despite international efforts to stop the practice, it is still astoundingly prevalent. In the developing world, a full one-third of women between the ages of 20 and 24 were married off as children, according to a 2010 UNICEF study.
Child marriage is most common in South Asia and sub-Saharan Africa, and it has damaging effects on families and societies. Widely considered a violation of human rights, it is linked to higher rates of child-bearing mortalities, infant mortality, physical and psychological health problems, poverty, illiteracy and gender inequality.
Study authors point to education as a possible solution to the problem.
There have been rigorous evaluations of interventions in Ethiopia and Malawi aimed at retaining girls in schools, with the result of delayed age at marriage, said Raj. We need better understanding of the degree to which girl education can reduce risk for early marriage among girls in South Asia.