Smoking and all-cause mortality in older people: systematic review and meta-analysis

Abstract

BACKGROUND Smoking is an established risk factor of premature death. However, most pertinent studies primarily relied on middle-aged adults. We performed a systematic review and meta-analysis of the empirical evidence on the association of smoking with all-cause mortality in people 60 years and older. METHODS A systematic literature search was conducted in multiple databases including MEDLINE, EMBASE, and ISI Web of Knowledge and complemented by cross-referencing to identify cohort studies published before July 2011. Core items of identified studies were independently extracted by 2 reviewers, and results were summarized by standard methods of meta-analysis. RESULTS We identified 17 studies from 7 countries. Current smoking was associated with increased all-cause mortality in all studies. Relative mortality (RM) compared with never smokers ranged from 1.2 to 3.4 across studies and was 1.83 (95% CI, 1.65-2.03) in the meta-analysis. A decrease of RM of current smokers with increasing age was observed, but mortality remained increased up to the highest ages. Furthermore, a dose-response relationship of the amount of smoked cigarettes and premature death was observed. Former smokers likewise had an increased mortality (meta-analysis: RM, 1.34; 95% CI, 1.28-1.40), but excess mortality compared with never smokers clearly decreased with duration of cessation. Benefits of smoking cessation were evident in all age groups, including subjects 80 years and older. CONCLUSIONS Smoking remains a strong risk factor for premature mortality also at older age. Smoking cessation is beneficial at any age.