Older people who smoke may think there's no reason to give up the habit. After all, hasn't the damage to their bodies already been done?
But it turns out there's a benefit to quitting even later in life. Research published Wednesday in the American Journal of Preventive Medicine finds that older adults who quit smoking in their 60s had a lower chance of dying in the years that followed than contemporaries who kept smoking.
"It's never too late," says Sarah Nash, an epidemiologist and one of the study's authors.
The results are based on data from more than 160,000 participants older than 70 who were part of the NIH-AARP Diet and Health Study. Participants completed questionnaires about their smoking history in 2004 or 2005 and were tracked until the end of 2011 to see who had died.
The study found that it's definitely best to avoid smoking entirely. During the follow-up period, 12 percent of participants who never smoked died, compared to 33 percent of current smokers. And the earlier people quit the better, but there was still a benefit even for late quitters. Of those who quit in their 30s, 16 percent died. In their 40s: 20 percent. In their 50s: 24 percent. And in their 60s: 28 percent.
Still, people who quit in their 60s had a 23 percent lower risk of death during the study than current smokers, says Nash, who conducted the research while she was a fellow at the National Cancer Institute.
One limitation of the study is that the "current smoker" category included anyone who was smoking when they completed the questionnaire, which means it likely included people who went on to quit during the follow-up period. But if that happened to a significant degree, the true mortality gap between people who smoke and those who quit would only be larger.
The researchers also looked at deaths from smoking-related diseases, including lung cancer, heart disease and respiratory infections, and saw similar trends.
The research also reinforces the well-known point that it's important to try to prevent people from picking up the habit in the first place. Most smokers start during their teenage years, according to the Centers for Disease Control and Prevention. And among current smokers, the earlier the study participants started, the higher their likelihood of dying during the follow-up period. Of those who started when they were younger than 15, 38 percent died, compared to 23 percent of those who started when they were 30 or older.
Until now there have been hints from other research, but no solid proof, that people in their 60s and 70s could benefit from quitting.
"Based on less substantial data, we've been telling the public that it's never to late to quit, because it will benefit health and prolong life," says Norman Edelman, a physician and senior scientific advisor to the American Lung Association who wasn't involved with the study. Now, he says, he'll have more concrete evidence to offer to patients, especially to older smokers who assume that the damage from years of tobacco use can't be reversed.
Edelman says he gives the same smoking cessation advice to older smokers as to younger ones: Use a program (the ALA has its own, as does the American Cancer Society) in conjunction with pharmaceutical help, such as nicotine replacement products or prescription medications (such as Chantix or Zyban). Your odds of success are greater if you use both, he says.
He says older smokers should be sure to speak with their physicians about potential side effects of tobacco cessation medications.
Katherine Hobson is a freelance health and science writer based in Brooklyn, N.Y. She's on Twitter: @katherinehobson.