The hazards of smoking and the benefits of cessation: a critical summation of the epidemiological evidence in high-income countries.
Level 1 - systematic review of randomized trials
Systematic synthesis and meta-analysis of epidemiological cohort studies.
PubMed 32207405 · doi:10.7554/eLife.49979
What was done
The author conducted an epidemiological summation and meta-analysis synthesising data from major cohort studies and population statistics in high-income countries (principally the US, UK, and Canada) from 1960 to 2020 to quantify smoking-attributable mortality and the survival benefits of cessation.
What was found
Cumulative smoking-related mortality reached approximately 41 million deaths across the US, UK, and Canada between 1960 and 2020. Every million cigarettes consumed corresponded to approximately one death in the US and Canada and slightly over one death in the UK. Smokers who initiated in early adult life and did not quit lost approximately 10 years of life expectancy compared to non-smokers. Up to two-thirds of deaths among persistent smokers were avoidable at non-smoking death rates, and former smokers retained only about a quarter of the excess risk of death compared to current smokers, with major risk reductions achieved by quitting before age 40.
Why it matters
This synthesis provides clear population-level metrics on the full scale of 21st-century smoking harms and reinforces that early cessation can avert nearly all excess mortality risk.
Limits
The abstract focuses exclusively on high-income countries (US, UK, Canada), limiting direct generalisability to low- and middle-income regions. Exact cohort participant counts, search criteria, and confidence intervals are omitted from the abstract text.
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