Quitting Smoking Decreases Death Risk Even in Older People

By Larry Hand
Medscape Medical News

June 11, 2012 — Smokers are at almost twice the risk of dying of any cause at older ages than people who never smoked, and contrary to popular belief, quitting smoking — even at an older age — reduces the risk for death, according to a study published in the June 11 issue of the Archives of Internal Medicine.

Carolin Gellert, from the Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Heidelberg, and colleagues conducted a systematic review and meta-analysis of medical literature and identified 17 published studies from 7 countries with data on how smoking affects all-cause mortality in people aged 60 years and older. Most studies into smoking's effects have involved middle-aged people. The studies analyzed in this report were from the United States, China, Australia, Japan, England, France, and Spain.

"In this review and meta-analysis on the association of smoking and all-cause mortality at older age, current and former smokers showed an approximately 2-fold and 1.3-fold risk for mortality, respectively," the researchers write.

"This review and meta-analysis demonstrates that the relative risk for death notably decreases with time since smoking cessation even at older age," they add.

The studies cited in the meta-analysis were conducted between 1987 and 2011 and involved study populations ranging from 863 to 877,243 participants. Across all of the studies, current smoking was associated with higher all-cause death compared with never smokers, with relative mortality averaging 1.83 (95% confidence interval [CI], 1.65 - 2.03). For former smokers, the relative mortality averaged 1.34 (95% CI, 1.28 - 1.40) compared with never smokers. The researchers report that smoking cessation benefits were evident through the highest ages, including people aged 80 and older, and that results were comparable between men and women.

The researchers found "a clear dose-response relation of increasing mortality with increasing number of cigarettes" smoked by the individuals. They also found that relative mortality decreased with age, from 1.94 (95% CI, 1.57 - 2.40) for people aged 60 to 69 years to 1.86 (95% CI, 1.55 - 2.22) for people aged 70 to 79 years, and to 1.66 (95% CI, 1.30 - 2.12) for people aged 80 years and older. Asian populations had lower relative mortality than European, US, and Australian populations.

"To our knowledge, this is the first systematic review and meta-analysis on the impact of smoking on all-cause mortality focusing on older people," the researchers write. "Summarizing the results from 17 cohort studies, we observed an 83% increased mortality for current smokers and a 34% increased mortality for former smokers compared with never smokers. Relative mortality of former smokers decreased with time since cessation."

In an accompanying editorial, Tai Hing Lamb, MD, from the University of Hong Kong School of Public Health, writes that the smoking cessation finding is especially valuable. "Many older smokers misbelieve that they are too old to quit or too old to benefit from quitting," he writes. "Because of reverse causality and from seeing deaths of old friends who had quit recently, some misbelieve that quitting could be harmful. A simple, direct, strong, and evidence-based warning is needed."

For clinicians who want to provide such a warning now, Dr. Lamb offers the acronym AWARD: A, ask about smoking; W, warn your patients about the great chance of dying from smoking-related disease; A, advise your patients to quit smoking and cut their risk for death; R, refer your patients to smoking cessation; and D, do it again until they quit.

In the meta-analysis, the researchers conclude, "[S]moking is a strong risk factor for premature mortality at older age. A dose-response relationship of the number of currently smoked cigarettes with mortality was observed in all age groups, even though the number of studies reporting such data are still rather limited. The longer the time since smoking cessation, the lower the [relative mortality] of older former smokers; this fact calls for effective smoking cessation programs that are likely to have major preventive effects even for smokers aged 60 years and older."

The study was supported by CHANCES project funded in the FP7 Framework Programme of DG-RESEARCH in the European Commission.The authors and editorialist have disclosed no relevant financial relationships.

Arch Intern Med. 2012;172:837-844, 845-846.