(HealthDay News) — Age at smoking initiation and cessation continue to be important predictors of mortality in U.S. adults over age 70, according to a study published online Nov. 29 in the American Journal of Preventive Medicine.
Sarah Nash, Ph.D., who conducted the study while at the U.S. National Cancer Institute, and colleagues collected data on 160,113 men and women, aged 70 and older, who took part in a national health study. Between 2014 and 2016, the researchers correlated age at death with the age when the participants started or stopped smoking. Causes of death were also noted, including lung cancer and other smoking-related cancers, as well as deaths from cardiovascular disease, stroke, diabetes, and respiratory diseases. The researchers also took age, gender, level of education, and alcohol use into account.
At the start of the study, the average age of participants was 75. Nearly 56 percent were former smokers, and 6 percent were current smokers. Men were less likely (31.2 percent) to have never smoked than women (48.0 percent). Men smoked more than women, and men were more likely than women to have started smoking at age 15 (19.0 versus 9.5 percent). Over an average follow-up of six years, 15.7 percent of the participants died. Among those who died, 12.1 percent had never smoked. Mortality rates increased among those who smoked and who quit smoking at later ages: 16.2 percent for those who quit in their 30s, 19.7 percent if they quit in their 40s, 23.9 percent for those in their 50s, and 27.9 percent for those in their 60s. Current smokers had the highest mortality rate during the follow-up period (33.1 percent).
“Younger age at initiation was associated with increased risk of mortality, highlighting the importance of youth and early-adult smoking on lifetime mortality risk, even among people who live to age 70 years,” Nash said in a journal news release. “In addition, former smokers were at substantially reduced risk of mortality after age 70 years relative to current smokers, even those who quit in their 60s. These findings show that smoking cessation should be emphasized to all smokers, regardless of age.”