Quitting smoking before 40 can reduce your risk of death by a smoking-related disease by 90%.
According to a 2013 study in the New England Journal of Medicine, quitting before the age of 40 reduces your chance of dying prematurely from a smoking-related disease by 90 percent, and quitting by age 54 still reduces your chance by two-thirds.
Even current smokers who quit after being diagnosed with cancer are better able to heal and respond to treatment, reducing the chance of death from some cancers by up to 40 percent.
Living with a smoker increases your chance of developing lung cancer or heart disease from secondhand smoke by as much as 30 percent. All told, smoking and exposure to tobacco smoke cause about 480,000 deaths a year.
Source: hopkinsmedicine.org
