More than 400,000 people could be living in “modern slavery” in the US, a condition of servitude broadly defined in a new study as forced and state-imposed labor, sexual servitude and forced marriage.

The Global Slavery Index, published on Thursday by Walk Free Foundation, describes modern slavery as a complex and often hidden crime that crosses borders, sectors and jurisdictions. The US number, the study estimates, is almost one hundredth of the estimated 40.3 million global total number of people it defines as being enslaved.

“The United States is one of the most advanced countries in the world yet has more than 400,000 modern slaves working under forced labor conditions,” said the group’s founder, Andrew Forrest, in a news release.

“This is a truly staggering statistic and demonstrates just how substantial this issue is globally. This is only possible through a tolerance of exploitation,” Forrest added.

The report estimates most victims of modern slavery live in Asia. North Korea has the highest prevalence of modern slavery globally, with one in 10 of the population, or 2.6 million people, victims of modern slavery.

A third, or 15 million, of victims of modern slavery enter through forced marriage, an issue that disproportionately affects women and girls. “Overall, the cultural practice of forced marriage places women at greater risk of exploitation, and the potential subjection to a life of servitude, financial bondage and sexual exploitation that comes with modern slavery,” the report said.

The report also argues the US figures are in themselves deceptive because the US exacerbates the global slavery problem by importing products, including laptops, computers, mobile phones, garments, fish, cocoa and timber, at risk of being produced through forced labor.

The group recommends making forced marriage illegal, creating a minimum marriage age of 18, a national database of trafficking and forced labor cases, and working to improve supply-chain transparency to help bring the US numbers down.

It estimates China is by far the largest source of at-risk goods, with the United States importing $122bn of electronics and clothing from the country. Vietnam was the second largest source with $11.2bn, and India third with $3.8bn.

Smaller values of goods were also sourced from Malaysia, Thailand, Brazil, Argentina, Japan, Taiwan, South Korea, Russia, Ghana, Ivory Coast and Peru.

“There is no quick solution to this and governments, businesses, and consumers alike must wake up to the fact that they must change their behavior if they wish to tackle this abhorrent issue, both at home and abroad,” Forrest wrote.

Walk Free’s methodology includes extrapolation using national surveys, databases of information of those who were assisted in trafficking cases, and reports from other agencies like the UN’s International Labour Organization.

But other anti-exploitation groups offer caution over Walk Free’s definition of slavery and the methodology it uses in calculating the numbers of people affected.

In a recent essay, What’s Wrong with the Global Slavery Index?, published in the Anti-Trafficking Review, the author, Anne Gallagher, argued that the term “modern slavery” seeks to encompass under its expansive umbrella a raft of exploitative practices and a myriad of victims.

“We don’t yet have universally accepted diagnostic criteria or credible tools of measurement – which means that universal, reliable calculation of the size of the problem, while an important goal to strive for, is not yet possible,” she wrote.