From CNN's Dan Gilgoff:

Christopher Hitchens' atheist manifesto was subtitled "how religion poisons everything," but a new polling analysis challenges that notion, finding that very religious Americans have higher levels of well-being than the rest of the country.

The most religious Americans show the highest levels of well-being as measured by factors ranging from physical and emotional health to self-evaluations of life to perceptions of work environment, according to a Gallup report released Thursday.

Americans for whom religion is an important part of everyday life and who attend religious services roughly once a week or more score an average 68.7 on a well-being index developed by Gallup and Healthways, a health consulting company.

Americans who are moderately religious or who are nonreligious, meanwhile, average 64.2 on the Gallup-Healthways well-being index.

Gallup Editor-in-Chief Frank Newport says that the gap is significant because there are typically few differences in the well-being index between Americans from different demographics.

"It's not like some people score zero and others score 100," Newport told CNN. "So when we find a difference of four of five points it's not only statistically significant, it's also substantively significant."

Newport said that the biggest difference between very religious and nonreligious Americans is in healthy behavior, which is mostly explained by a negative correlation between smoking and religiosity.

"We now have the solution to the health care crisis," Newport joked. "If we're interested in lowering health care costs in America, we need to increase the prevalence of religion."

Though the survey didn't gauge whether religiosity led to higher levels of well being or vice versa, Newport speculated that religiosity was the likely driver.

"All religions have different mechanisms that would plausibly lead to higher well-being, including social networks and ways of dealing with stress, but we can't prove that," he said. "It is possible that people with higher levels of well-being choose to be religious."

The Gallup analysis draws on more than 550,000 interviews. Newport said that the polling firm asks 1,000 Americans a night about indicators of well being and about levels of religiosity.

The analysis controlled for other factors that typically influence levels of religiosity, including age, gender, race and ethnicity, region, state, socioeconomic status, marital status and child-bearing status.

According to Gallup surveys, 44 percent of Americans are very religious, 30 percent are nonreligious and 27 percent are moderately religious.