Large financial incentives may help increase long-term quit-smoking rates in low-income smokers, a new study suggests.

Swiss researchers gave out incremental payments of up to $1,650 to smokers who underwent biochemical testing to prove they had not been smoking. The payments helped more than one-third of them to quit long term, HealthDay reports. The smokers in the study did not receive face-to-face counseling or medications.

Three months after the study began, 44 percent of smokers who received payments said they had been continually smoke free, compared with 6 percent of those who were not paid. Those who were paid to quit were still more likely to be smoke free even after incentive payments stopped, the researchers report in the Journal of the American College of Cardiology.