Intended for healthcare professionals


Just one cigarette a day seriously elevates cardiovascular risk

BMJ 2018; 360 doi: (Published 24 January 2018) Cite this as: BMJ 2018;360:k167
  1. Kenneth C Johnson, adjunct professor
  1. School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
  1. Correspondence to: Ken47Johnson{at}

Only total cessation will protect people and populations from tobacco’s toxic legacy

Any assumption that smoking less protects against heart disease or stroke has been dispelled this week in the BMJ (doi:10.1136/bmj.j5855). In a large meta-analysis of observational studies, Hackshaw and colleagues show the unexpected extent to which smoking even one cigarette a day is associated with major cardiovascular risk.1

The results are compelling. Smoking one cigarette a day was associated with a 48% (all studies) to 74% (studies controlling for confounders in addition to age and sex) increase in the risk of coronary heart disease (CHD) in men, a 57% to 119% increase in CHD risk for women, and a roughly 30% increase in the risk of stroke for both men and women.

One cigarette a day accounted for fully half of the excess CHD risk associated with smoking 20 a day in men and for one third of the risk in women. For stroke, one cigarette accounted for roughly one third of the risk associated with smoking 20 a day.

The meta-analysis is impressive, based on …

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