A new study suggests that people are more likely to quit smoking when the trend declines.

Researchers at the University of California found that as smoking declined, the remaining smokers actually smoked less and were more likely to quit than to stick with the deadly habit. The recent findings challenge the concept of harm reduction which is based on the theory that as smoking prevalence declines, the remaining "hard core" smokers will be less likely or able to quit smoking, a process called hardening.

However, researchers found that the remaining smokers are softening.

"The fact that the smoking population is softening has important implications for public health policy," Stanton A. Glantz, senior author of the study, said in a statement. "These results suggest that current tobacco control policies have been leading to softening of the smoking population without the need to promote new recreational nicotine products like e-cigarettes."

For the study, researchers collected and analyzed data spanning 18 years in the united States and six years in the European Union.

They found that for each 1 percent drop in the fraction of the population that smoked, the number of smokers who tried to quit increased by 0.6 percent in the United States and remained stable in Europe. They also showed that the percentage of U.S. smokers who quit increased by 1.13 percent, while daily cigarette consumption among remaining smokers dropped by 0.32 cigarettes in the United States and 0.22 cigarettes in Europe. Overall U.S. cigarette consumption levels dropped over time, while those associations remained stable in Europe.

Researchers said that in addition to challenging the concept of harm reduction, the findings also challenge the need to promote new forms of nicotine delivery, such as e-cigarettes, since the smoking population continues to quit smoking as a result of proven policies and interventions.

"We show that there is no real need to distribute e-cigarettes as part of a tobacco policy package because the smoking population is softening," Margarete C. Kulik, first author of the study, said in a statement. "Tobacco control policies should continue to move the population down these softening curves rather than changing policies to promote new forms of nicotine delivery, especially ones like e-cigarettes that are very appealing to children."

The findings are detailed in the journal Tobacco Control.