African American couples are more likely than others to share core religious beliefs and pray together at home — factors that have been linked to greater happiness in marriages and relationships, according to a study that has just been released.

In what is described as the first major look at relationship quality and religion across racial and ethnic lines, researchers report a significant link between relationship satisfaction and religious factors for whites, Hispanics and African Americans. The study, released Tuesday, appears in August’s issue of the Journal of Marriage and Family.

True to the aphorism, couples who pray together stay together, study co-author Bradford Wilcox, director of the National Marriage Project at the University of Virginia, said.

The study found that 40 percent of blacks in marriages and live-in relationships who attended religious services regularly had a partner who did the same, compared with 29 percent of non-Hispanic whites and 29 percent of Hispanics.

White couples, in general, reported greater relationship satisfaction than other groups, presumably because of income and educational advantages, the study says. But the racial gap lessens when religious similarities come into the mix.

“What this study suggests is that religion is one of the key factors narrowing the racial divide in relationship quality in the United States,” Wilcox said.

The strongest difference-maker for couples was spiritual activities such as praying or reading the Bible at home. “It adds another level of closeness to a relationship,” Wilcox said.

The study’s results are based on a recent analysis of a 2006 U.S. survey of 1,387 adults ages 18 to 59. Nearly 90 percent were married; the others were living together.