News Release

Global declines in adolescent childbearing related to national income, education expenditures

Median adolescent birth rate among nations dropped by 40 percent from 1990 to 2012

Peer-Reviewed Publication

Columbia University's Mailman School of Public Health

New York -- Researchers at Columbia University's Mailman School of Public Health found that an important explanation for declining rates of global adolescent fertility is rising national wealth and expenditures on education. Income inequalities were associated with higher adolescent birth rates, and slower rates of decline in adolescent birth rates. Results are published online in the Journal of Adolescent Health.

"Declines in global adolescent birth rates were profoundly and independently shaped by national income, income inequalities, and expenditures on education," said John Santelli, MD, Chair and Professor of Population and Family Health at Columbia University's Mailman School of Public Health. Co-authors included Xiaoyu Song and Samantha Garbers from Columbia, Vinit Sharma of the United Nations Population Fund, and Russell Viner of University College London.

The study is the most comprehensive to date of these social determinants and their relationship to trends in global adolescent childbearing. It adds support to the growing body of evidence that suggests narrowing income inequality and increasing education opportunities can improve health and well-being for young people.

The findings parallel previous research on social and education influences on adolescent health reviewed earlier this year by the Lancet Commission on Adolescent Health and Wellbeing. Drs. Santelli and Viner were members of the Commission.

Using data from the World Bank, the researchers examined the national income (per capita GDP), income inequality within nations (the Gini Index), and national expenditures on education as a percentage of GDP and their association with adolescent birth rates and rates of decline in adolescent birth rates among 142 nations over the period 1990-2012.

The median adolescent birth rate among nations fell 40 percent from 72.4 per 1,000 in 1990 to 43.6 per 1,000 in 2012.

Adolescent birth rates in 2012 varied more than 200-fold among the 142 nations examined. By region, the highest rates were found in Sub- Saharan Africa and the lowest rates were in Europe and Central Asia and other high-income nations. The U.S. still has among the highest rates of adolescent birth among high income countries, despite a decline of 51 percent between 1990 and 2012 -- the period of time for this study.

Adolescent birth rates were based on the number of births per 1,000 adolescent women (15-19 years). GDP in current U.S. dollars was used as the indicator of wealth. The Gini Index (range 0-100), the most commonly used measure of national income inequality was also used for this study. A Gini score of 0 corresponds with perfect equality (where everyone has the same income) and a score of 100 corresponds with perfect inequality (i.e., one person has all the income). Thus, a higher national Gini Index score indicates greater income inequality within a nation.

While inequalities showed little change over time, regions with lower income inequalities had more rapid rates of decline in adolescent birth rates. The largest regional declines over the 22-year time period occurred in South Asia (70 percent), Europe/Central Asia (63 percent), and the Middle East/North Africa (53 percent)--"regions with lower income inequality," noted Dr. Santelli.

"We hypothesized that GDP, Gini, and educational expenditures would be independently associated with national rates of adolescent births and trends in these rates. They were." said Dr. Santelli.

"Reducing poverty and income inequalities and increasing investments in education should be essential components of national policies to prevent adolescent childbearing," said Dr. Santelli.


This study is supported by Heilbrunn Department of Population and Family Health, Columbia University's Mailman School of Public Health.

Columbia University's Mailman School of Public Health

Founded in 1922, Columbia University's Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Mailman School is the third largest recipient of NIH grants among schools of public health. Its over 450 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change & health, and public health preparedness. It is a leader in public health education with over 1,300 graduate students from more than 40 nations pursuing a variety of master's and doctoral degree programs. The Mailman School is also home to numerous world-renowned research centers including ICAP (formerly the International Center for AIDS Care and Treatment Programs) and the Center for Infection and Immunity. For more information, please visit

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