Former smokers outnumber current smokers in the U.S. by about 18 million. However, they still have an increased mortality risk compared to those who never smoked. Those who have quit smoking can further improve their odds by following helpful lifestyle recommendations such as eating a healthy diet, getting adequate amounts of physical activity and sleep, and limiting alcohol consumption.

That's what researchers, led by a team from the National Cancer Institute, found when they looked at how adherence to evidence-based guidelines for a healthy lifestyle affected former smokers’ risk for all-cause mortality. Former smokers who had the greatest adherence to the recommendations had a 27 percent lower risk of all-cause mortality than those with the least adherence. They also had a reduced risk of death from cancer, cardiovascular disease and respiratory disease.

Former smokers who most closely followed the recommendations had a 27 percent lower risk of all-cause mortality than those who adhered to them the least.

The reductions in risk achieved by more closely following the guidelines were seen regardless of health status, comorbid conditions, the number of cigarettes formerly smoked per day, the number of years since quitting smoking and the age at which participants began smoking.

Maki Inoue-Choi, corresponding author on the study, told TheDoctor the findings suggest that the health benefits of these lifestyle recommendations can benefit all former smokers, regardless of how much they smoked in the past.

“We were pleased to see robust associations regardless of prior smoking patterns and how long it had been since study participants quit smoking before the start of the study,” said Inoue-Choi, a staff scientist at the National Cancer Institute.

The findings come from information provided by almost 160,000 people who self-identified as former smokers and were participating in the National Institutes of Health - AARP Diet and Health Study, a prospective study of more than 550,000 U.S. adults between the ages of 50 and 69 years old.

Participants filled out a questionnaire addressing demographic information and lifestyle factors when they enrolled in the study, and they completed another risk factor questionnaire 12 months later. The former smokers were assigned scores based on their responses regarding evidence-based lifestyle recommendations for body weight, diet, physical activity and alcohol consumption. Higher scores indicated better adherence to the guidelines. Individual scores were added together for an overall adherence score.

Former smokers who had the highest scores for adherence to body weight recommendations had a 14 percent decrease in all-cause mortality risk compared to those with the lowest overall score; those with the highest scores for adherence to diet recommendations had a nine percent decrease in all-cause mortality risk; those with the highest scores for adherence to physical activity recommendations had a 17 percent decrease in risk; and those with the highest scores for adherence to alcohol use recommendations had a four percent decrease in risk.

Inoue-Choi points out that as encouraging as the findings are, they are from a single study with mostly white participants of higher socioeconomic status. Future studies of more diverse populations are needed to replicate and verify these findings.

The study and a related editorial are published in JAMA Network Open.