Unprecedented changes are occurring worldwide as fertility and mortality rates decline in most countries and as populations age. These changes affect individuals, families, governments, and private-sector organizations as they seek to answer questions related to health care, housing, social security, work and retirement, caregiving, and the burden of disease and disability.
NIA has pioneered cross-national research, sponsoring collaborative international projects, and disseminating findings in aging-related conditions and concerns affecting people worldwide. Significantly, NIA’s Health and Retirement Study has served as the model for similar large-scale longitudinal studies in other countries. These include the English Longitudinal Study of Ageing (ELSA), the Study of Health, Ageing, and Retirement in Europe (SHARE), the Mexican Health and Aging Study (MHAS), the Korean Longitudinal Study of Aging (KLoSA), and the Chinese Health and Retirement Survey (CHARLS).
NIA also collaborates with the World Health Organization and others on additional research efforts on global aging issues.
DBSR has encouraged the development of harmonized international studies that use measures that are comparable to the Health and Retirement Study (HRS).
Global Health and Aging Report  (PDF , 15.7M)
As both the proportion of older people and the length of life increase throughout the world, key questions arise. Will population aging be accompanied by a longer period of good health, a sustained sense of well-being, and extended periods of social engagement and productivity, or will it be associated with more illness, disability, and dependency? How will aging affect health care and social costs? Are these futures inevitable, or can we act to establish a physical and social infrastructure that might foster better health and wellbeing in older age? How will population aging play out differently for low-income countries that will age faster than their counterparts have, but before they become industrialized and wealthy? This brief report, jointly issued by the WHO’s Department of Ageing and the Life Course and the NIA attempts to address some of these questions, emphasizing the central role that health will play in coming years.
Why Population Aging Matters: A Global Perspective 
This booklet provides a succinct description of population trends that are transforming the world in fundamental ways. The report, using data from the United Nations, US Census Bureau, and the Statistical Office of the European Communities as well as regional surveys, identifies nine emerging trends in global aging. These trends present a snapshot of challenges and opportunities that will stimulate a cross-national scientific and policy dialogue. The booklet was prepared for the March 15, 2007, Summit on Global Aging, hosted by the U.S. State Department in collaboration with the National Institute on Aging.
An Aging World 2008  (PDF, 6.5M)
Issued in July 2009, this update to the Census Bureau series on global aging was commissioned by the NIA to examine nine international population trends identified in 2007 by the NIA and the U.S. Department of State (Why Population Aging Matters: A Global Perspective). An Aging World: 2008” contains detailed information on life expectancy, health, disability, gender balance, marital status, living arrangements, education and literacy, labor force participation and retirement, and pensions among older people around the world. For additional information, please visit the Census Bureau .
The National Institute on Aging: A Catalyst for Global Aging Research  (PDF, 81K)
NIA leads the Federal research effort to increase our understanding of the nature and implications of aging and to find ways to extend the healthy, active years of life. Established in 1974, NIA’s mission is to improve the health and well-being of older people through research.
Research Highlights: Cross-National Research on Aging  (PDF, 117K)
In nearly all regions of the world, the population ages 65 and older is growing faster than the total population,challenging existing health services, family relationships, social security, and pension programs. To help address these challenges, the Behavioral and Social Research Program of the National Institute on Aging (NIA) sponsors a wide range of data collection efforts and research related to population aging. This Research Brief highlights cross-national datasets partially or fully funded by NIA, how these data are used to address key research questions, and where people can go for more information.
Aging in Sub-Saharan Africa: Recommendations for Furthering Research  (PDF, 2.1M)
In 2006, 64 percent of the worldwide population aged 60 and older resided in developing countries, and this proportion is projected to increase to nearly 73 percent by 2030. Yet the limited understanding of the demographics of aging in most developing countries stands in stark contrast to the comparatively well-documented course and implications of aging in developed countries. (National Research Council, 2006)
Preparing for an Aging World: The Case for Cross-National Research 
The projected growth in the numbers and proportions of the world's older population poses an array of challenges to policy makers. How do changes in the ratio of workers to retirees affect the ability of societies to fund old-age security systems? Are we living healthier as well as longer lives, or are our added years accompanied by disabilities and generally poor health? In what ways can the structure and the delivery mechanisms of health systems best adapt to the needs of older populations with a higher prevalence of chronic disease? How do changing family structures affect the demand for public transfers of money, time, and living space? Will population aging lead to lower levels of aggregate saving, investment and productivity growth? Will health care costs rise or decline relative to other costs? (National Research Council, 2001)