WASHINGTON: Americans are among the least likely to be concerned about retirement security, or to view the growing number of older people as a major concern, a new global study finds.

The analysis of surveys across 21 nations by the Pew Research Center is timely because it details some of the benefits of immigration as lawmakers in the U.S. debate an overhaul of immigration laws: higher population growth and a slower rate of population aging.

The surveys found that people in nations where the population is aging less swiftly, such as the U.S., are less likely to be worried about their old-age futures than those in parts of Europe and East Asia that are grappling with swiftly shrinking workforces and increasing pension costs.

The findings show an increasing economic importance of foreign-born residents in the United States. Younger immigrants who arrive in the United States typically find jobs and start families.

Changes in the world’s demographics “could alter the distribution of global economic power over the coming decades,” said Rakesh Kochhar, a senior researcher at Pew.

“Demographically, at least, America is poised to maintain its global status while many European and East Asian nations shrink either in absolute or relative terms. India and several African nations may benefit from the projected demographic trends,” Kochhar said.

“Immigration is the main reason why population growth in the U.S. will be much greater than in Europe or East Asia.”

Just 26 percent of Americans said aging in their country is a “major problem,” according to the report, which was released Thursday. Concern about aging was highest in Asia — 87 percent in Japan, 79 percent in South Korea and 67 percent in China. In Europe, more than half of those surveyed in Germany and Spain pointed to increases in the older population as a major problem in their countries.

Americans were relatively optimistic that they will have an adequate standard of living in their old age. About 63 percent of those surveyed said they were “very confident” or “somewhat confident” about their retirement security. They ranked near the top along with other countries with younger populations or strong economies: China, Brazil, Nigeria, South Africa, Kenya and Pakistan.

Americans’ confidence about retirement security may not always match up with reality. Polling last year by the AP-NORC Center for Public Affairs Research found that most Americans over 40 underestimated the costs of their likely long-term care needs and were not doing much to prepare for them.