It’s always a good time to quit smoking and enjoy the benefits that come from it, according to a recent study performed on more than 100,000 women carried out between 1980 and 2004.

“The harms of smoking are reversible and can decline to the level of nonsmokers. For some conditions like chronic obstructive pulmonary disease, it can take more than 20 years, but there is a rapid reduction for others. It’s never too early to stop , and it’s never too late to stop,” study lead author Stacey Kenfield, ScD, of the Harvard School of Public Health in Boston, said, as quoted by the Washington Post.

Kenfield and colleagues found that, within five years, the women participating in the study experienced a 13 percent reduction in the risk of death from all causes, a 47 percent risk reduction in heart disease-related deaths, and a 27 percent reduction in the risk of death from stroke.

Moreover, the study revealed that, within 20 years of smoking, the risk of dying among former smokers was similar to that of lifetime nonsmokers for most causes of death, excepting lung cancer. It took 30 years for that risk to disappear.

“Quitting reduces the excess mortality rates for all major causes of death examined,” the study said.

The study also confirmed that smoking is a potent cause of disease. “Our findings indicate that 64 percent of deaths in current smokers and 28 percent of deaths in past smokers are attributable to smoking,” the study said.

Those smoking 35 or more cigarettes a day were 115 times more likely to develop chronic bronchitis and emphysema. The risk of developing cancer in their case was increased by 40 times. “Tobacco use remains the leading preventable cause of death” worldwide, with more than 5 million people dying from lung cancer, heart disease and other illnesses annually, according to the World Health Organization. The figure may rise to 10 million a year by 2030.

The authors concluded that “implementing and maintaining school tobacco prevention programs, in addition to enforcing youth access laws, are key preventive strategies. Effectively communicating risks to smokers and helping them quit successfully should be an integral part of public health programs.”

The study appeared in the May 7 issue of The Journal of the American Medical Association.