For the first time more than a decade, Americans appear to be smoking more.

A confluence of factors — from a better jobs market to cheaper gasoline to reductions in government anti-smoking programs — are driving a monthslong pickup in cigarette sales, analysts say. If current trends hold, 2015 could mark the first year since 2002 that sales volumes increase.

Not even tobacco companies are suggesting the long-term decline in smoking in the U.S. is reversing itself. Indeed, executives predict annual volumes will keep falling over time.

But recent data pointing to a slight increase in pack sales this year nonetheless underscore worrisome trends for public health officials. While the number of smokers in the United States has steadily declined, some smokers now seem to be lighting up more. Others are turning to chewing tobacco and electronic cigarettes to supplement cigarette habits rather than quit.

To public-health groups, any signs that the declines in smoking might be leveling off is cause for alarm and renewed anti-smoking efforts.

“Any time cigarette sales aren’t going down, that’s cause for concern,” said Vince Willmore, spokesman for the Campaign for Tobacco Free Kids. “We’re talking about the No. 1 cause of preventable death in our country.”

This year’s apparent bounce largely reflects the improving economy, particularly rising employment, analysts say. Gasoline prices are also a factor. Smokers as a group tend to have lower incomes than nonsmokers, and some are using the money they’re saving at the pump to buy cigarettes.

“Those gas price savings are a big benefit,” said Vivien Azer, an analyst at Cowen & Co. Sixty percent of cigarette sales happen at convenience stores and gas stations, she said.

Tobacco companies continue to spend aggressively on marketing, and the industry has been profiting from those efforts. At Reynolds American Inc., the second-largest U.S. tobacco seller, cigarette volumes rose 12 percent during the first nine months of 2015, including sales from its recently acquired Newport brand, according to company filings. Altria Group Inc., the No. 1 seller and the maker of Marlboro, reported a 1.5 percent increase.

Both companies say industrywide volume actually fell marginally during the first nine months of the year. Since 1964, when the U.S. surgeon general released the first report on smoking and health, the smoking rate among U.S. adults has fallen to 18 percent from 42 percent, as of data released in 2014. Many executives predict that over time U.S. pack sales will continue to fall by 3 percent to 4 percent annually.

That’s one reason large tobacco companies have pushed aggressively into the fast-growing market for e-cigarettes. These battery-powered devices, which deliver a puff of nicotine-laced vapor, are seen as less harmful than traditional cigarettes.

But e-cigarette use has also exploded among teenagers, a development some anti-smoking groups warn could hook a new generation on nicotine.

The shift comes at a time when government anti-smoking efforts have lost some momentum. In previous years, increased excise taxes and government-sponsored prevention and cessation programs had helped reduce smoking. The federal excise tax on cigarettes was last increased in 2009, when the tax on a pack went up by 62 cents — and smoking declined markedly. There has not been a federal excise tax increase since.

“The bottom line is that when we implement effective strategies to reduce tobacco use, especially cigarette tax increases, cigarette sales go down,” said Willmore of the Campaign for Tobacco Free Kids. “When we don’t implement those strategies, cigarette sales level off.”