A large US study has identified the right age to quit smoking to avoid increased risks of death.
People who quit smoking before age 35 have similar death rates over a given period of time to those who have never smoked.
Those who quit smoking at older ages still had substantial benefits over those who continued to smoke, but the death rate exceeded that of those who quit before age 35.
What is the right age to quit smoking?
For example, ex-smokers who quit between the ages of 35 and 44 had a 21% higher rate of death from any cause compared to those who had never smoked. And those who quit smoking between the ages of 45 and 54 showed a 47 percent higher all-cause mortality rate than those who never smoked.
“Among men and women of various racial and ethnic groups, smoking was associated with at least twice the all-cause mortality rate compared to never smokers,” wrote the authors of the study, published in the journal JAMA Network Open.
“Smoking cessation, particularly at younger ages, was associated with substantial reductions in excess mortality relative to continued smoking,” the scientists wrote.
A large study
This is the third large study to suggest that age 35 may be the right age to quit smoking, especially for young smokers, says John P. Pierce, professor emeritus in the Department of Family Medicine and Public Health from the University of California, San Diego, USA.
“It has long been known that the sooner a smoker quits, the better it is for him. But now we can be more specific about that age,” wrote Pierce, who was not involved in the new research.
The new study used data from the US National Health Interview Survey, a questionnaire-based survey used to monitor the health status of the US population, and the National Death Index, a database of the nation’s death records.
The analysis included survey data from more than 550,000 adults who completed questionnaires between January 1997 and December 2018 and were aged 25 to 84 at the time of recruitment.
These include current smokers, ex-smokers and people who have never smoked, or rather people who have smoked less than 100 cigarettes in their lifetime.
What does the data show?
According to the National Death Index, nearly 75,000 of these study subjects had died by the end of 2019. Compared to those who had never smoked, current smokers showed a significantly higher rate of death from all causes overall, as well as higher rates of death from cancer, heart disease and lung disease in particular.
White non-Hispanic smokers showed the highest all-cause mortality rate, which was three times that of never smokers. Non-white smokers, including both Hispanics and non-Hispanics, had slightly lower death rates, about twice that of never smokers.
This may be related to the fact that these participants reported smoking fewer cigarettes per day on average; they start smoking at older ages; and are less likely to smoke daily compared to white subjects.
“These results remind us that reducing smoking intensity (number of cigarettes per day) should be one of the goals of tobacco control programs,” Price wrote.
Crucially, while smoking was linked to a higher risk of death in all racial and ethnic groups surveyed, “smoking cessation was associated with substantially reversed risks for all groups,” the study authors wrote.
Why is it useful to know what is the right age to quit smoking?
In particular, those who quit by age 45 reduced their increased risk of death by up to 90%, and those who quit before age 35 had death rates very close to those of to those who have never smoked.
The study also found that the longer it had been since a person quit smoking, the closer the death rate was to that of a person who had never smoked.
Now that there’s a quit age as a deadline, young smokers may be more motivated to quit, Price wrote.
“Without a proximal goal, it’s tempting for smokers to abandon a quit attempt using excuses like ‘I don’t have to do it right now.’ The study … provides the data needed to establish a motivating proximate goal of quitting smoking before age 35,” he wrote.
But all is not lost after the age of 35; as the study suggests, quitting at older ages reduces the risk of death, just not as dramatically.
Limitations of the study
The research has some limitations. For example, information on subjects’ smoking habits was collected at a single point in time, so some subjects may have quit or started smoking after being surveyed.
“Thus, both the true dangers of smoking and the true benefits of quitting may be underestimated in this study,” the authors cautioned.
However, the study still suggests that quitting smoking greatly reduces the risk of premature death, especially if you quit at the right age.