The Christian Century

(RNS) Rest on the Sabbath. Heed Old Testament dietary codes. And be ready for Jesus to return at any moment.

If these practices sound quaint or antiquated, think again. They're hallmarks of the Seventh-day Adventist Church, the fastest-growing Christian denomination in North America.

Newly released data show Seventh-day Adventism growing by 2.5 percent in North America, a rapid clip for this part of the world, where Southern Baptists and mainline denominations, as well as other church groups are declining. Adventists are even growing 75 percent faster than Mormons (1.4 percent), who prioritize numeric growth.

For observers outside the Seventh-day Adventist Church, the growth rate in North America is perplexing.

"You've got a denomination that is basically going back to basics ... saying, `What did God mean by all these rules and regulations and how can we fit in to be what God wants us to be?'," said Daniel Shaw, an expert on Christian missionary outreach at Fuller Theological Seminary in Pasadena, Calif. "That's just totally contrary to anything that's happening in American culture. So I'm saying, `Whoa! That's very interesting.' And I can't answer it."

Seventh-day Adventists are asking a different question: Why isn't the church growing much faster on these shores, which is home to just 1.1 million of the world's 16 million Adventists? Despite its North American roots, the church is growing more than twice as fast overseas.

"We don't feel that we're growing very much, and that is a source of concern, especially for North America," said Ron Clouzet, director of the North American Division Evangelism Institute at Andrews University in Berrien Springs, Mich. Hispanic Adventists are "the one group that is growing very well," he added. "If we didn't have that group, we would look even more dismal."

With Saturday worship services and vegetarian lifestyles, Seventh-day Adventism owns a distinctive niche outside the Christian mainstream. But being different is turning out to be more of an asset than a liability.

Since the mid-19th century when the movement sprang up in New Hampshire, Seventh-day Adventism has had an urgent mission to bring the gospel -- with a distinctive emphasis on Christ's imminent second coming -- to the ends of the earth. Adventists find the essence of their mission in Revelation 14:12, where the end of the age "calls for patient endurance on the part of the people of God who keep his commands and remain faithful to Jesus."

The church's traditional, global focus is now bearing fruit in new ways. Newly arrived immigrants in the United States often come from parts of Latin America or Africa where Seventh-day Adventism has long-established churches, schools and hospitals.

Those who migrate from Brazil to Massachusetts, or from Mexico to Texas, are apt to find familiarity in a local Adventist church led by a pastor who knows their culture and speaks their native language, said Edwin Hernandez, a research fellow at the Center for the Study of Latino Religion at the University of Notre Dame.

Immigrants aren't the only ones embracing Seventh-day Adventism. Many in the general public have noticed Adventists tend to be superstars of good health and longevity; research shows they tend to live 10 years longer than the average American. With strong track records for success in health and education, Adventists find they get a hearing among skeptics who share those priorities.

Publicized research on Adventists' health "has helped bring some objective evaluation of Adventism... particularly all up and down the West Coast," said G. Alexander Bryant, executive secretary for the denomination's North American division. "So we talk to people about our lifestyle."

Some newcomers to Adventism also appreciate the church's clarity about what's expected of Christ's followers. Diana Syth of Kent, Wash. attended many types of Protestant churches for years. But she said she "never got the information I needed to know about what it meant to be a Christian" until she and her husband learned of Seventh-day Adventism from a sibling six years ago.

"My (adult) son has seen a change in us," Syth said. "He sees a new calmness in us. There's hope where there wasn't hope before."

Adventists are also reaping the rewards of their extra efforts in evangelism. Responding to a national initiative, more than 80 percent of the 6,000 Adventist churches in North America staged weeks-long outreach events in hotels and other settings in 2009.

Bryant said in an ordinary year, one-third to one-half of Adventist congregations put on such events, and North American church growth rates would hover around 1.7 percent -- still high enough to top the rates of other large denominations in North America.

Creativity seems to be paying dividends, too. The church has seen some of its strongest gains come in non-religious regions such as the Pacific Northwest. In Washington, for instance, the denomination has established "Christian cafes," where people can relax and ask questions without feeling the pressures of church.

"You're not necessarily inviting them to church," Bryant said. "You're just sitting around, talking with people, building relationships -- and slowly talking to them about Christ."