Just one cigarette a day seriously elevates cardiovascular riskBMJ 2018; 360 doi: https://doi.org/10.1136/bmj.k167 (Published 24 January 2018) Cite this as: BMJ 2018;360:k167
- Kenneth C Johnson, adjunct professor
- School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
- Correspondence to:
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 …