Smoking kills. Every day, 1,300 Americans die from complications related to cigarette smoking, says the Centers for Disease Control and Prevention, so it's anyone's best interest to quit while they're ahead.

But as any smoker would tell you, it's not easy. In fact, only 15 to 20 percent of people who attempt to quit smoking ultimately succeed, according to recent reports. Some turn to vaping and e-cigarettes as temporary relief while they make inroads toward a smoke-free life, but new research suggest it's not really that effective.

Why You Should Quit Smoking Now

But a new study conducted by researchers at the Vanderbilt University Medical Center might convince you to throw those cancer sticks out for good. They studied nearly 9,000 participants over a period of 25 years, during which 284 cases of lung cancer occurred. Of those diagnosed, 93 percent were heavy smokers — those smoked at least one pack of cigarettes a day for 21 years or more.

The findings were published in the Journal Of The National Cancer Institute earlier this month.

The good news? Risks of developing lung cancer dropped by 39 percent five years after a person quit smoking entirely. Even better news? The researchers found that the risk continued to fall as the years passed.

The bad news, however, is that even 25 years after quitting, their risk was still three times higher than a person who had never smoked in their life.

"While the importance of smoking cessation cannot be overstated, former heavy smokers need to realize that the risk of lung cancer remains elevated for decades after they smoke their last cigarette, underscoring the importance of lung cancer screening," said senior author Matthew Freiberg.

Lung Cancer Screening

Current federal guidelines on insurance allow current and former smokers to be eligible for lung cancer screening. However, people who have not smoked a cigarette for 15 years or more are excluded. But in the study, the researchers found that 40 percent of lung cancer cases occurred 15 years after the person quit, which suggests the terms of insurance coverage for those presumed to be at risk of the disease must be adjusted.

Cigarette smoking is a dangerous, life-threatening habit that is linked to a bevy of diseases, including 16 different types of cancer. As of now, more than 16 million Americans are living with a disease caused by smoking, says the CDC. It is the leading cause of preventable death. Now is the best time to quit, according to coauthor Hilary Tindle.

"The fact that lung cancer risk drops relatively quickly after quitting smoking, compared to continuing smoking, gives new motivation," she said.