MANCHESTER, Ky. - When smoking first swept the U.S. in the early decades of the 20th century, it took hold among the well-to-do. Cigarettes were high-society symbols of elegance and class, puffed by doctors and movie stars.
By the 1960s, smoking had exploded, helped by the distribution of cigarettes to soldiers in World War II. Half of all men and a third of women smoked.
But as evidence of smoking's deadly consequences has accumulated, the broad patterns of use by class have shifted.
A new analysis of federal smoking data released on Monday shows that the disparity between impoverished and better-off Americans is increasing. The national smoking rate has declined steadily, but there is a deep geographic divide.
In the affluent suburbs of Washington, D.C., only about 1 in 10 people smoke, according to the analysis, by the Institute for Health Metrics and Evaluation. But in poorer places like Clay County in eastern Kentucky nearly 4 in 10 do.
"It's just what we do here," said Ed Smith Jr., 51, holding up his cigarette in a hand callused from his job clearing trees away from power lines. Several of his friends have died of lung cancer, and he has tried to quit, but so far has not succeeded.
The new study, which evaluated federal survey data from 1996 to 2012 to produce smoking rates by county, offered a rare glimpse beneath the surface of state-level data. It found that affluent counties across the nation have experienced the biggest, and fastest, declines in smoking rates, while progress in the poorest ones has stagnated.
The findings are particularly stark for women: About half of all high-income counties showed significant declines in the smoking rate for women, but only 4 percent of poor counties did.
This growing gap in smoking rates between rich and poor is helping drive inequality in health outcomes, experts say, with, for example, white women on the lowest rungs of the economic ladder now living shorter lives.
Americans with a high school education or less represent 40 percent of the population, but they account for 55 percent of the nation's 42 million smokers, according to a New York Times analysis of health survey data.
Health experts say this finer understanding of who still smokes shows that public health officials need to refocus anti-smoking efforts on the poor and working class.
But, even in Clay County, change could be coming. When Manchester's ban on smoking in public places went into effect, it was hard to tell who at the Huddle House restaurant hated it more: the clientele or the staff.
Two years later, Mike Feltner, a cook, was puffing stealthily on an electronic cigarette (Marlboro flavor) while cooking eggs. He said all four of the smokers on the staff now used the devices.
"This is a new phase in this town," he said. "Everybody's doing it. Young people, old people, everyone."