By Melanie Hinze
Following smoking cessation, cardiovascular disease (CVD) risk remains high for 10 to 15 and possibly up to 25 years in past heavy smokers, according to a retrospective analysis of Framingham Heart Study data, published in the Journal of the American Medical Association.
Professor Geoffrey Tofler, Professor of Preventative Cardiology at the University of Sydney and Staff Specialist in Cardiology at Royal North Shore Hospital, said we should continue to encourage and motivate smokers to quit by the promise of a rapid reduction in heart attack risk, with prior estimates of a halving in risk of heart attack by one year of abstinence. However, the time course of a full return to the baseline risk of a nonsmoker had not been well defined.
This observational cohort study followed 8770 participants for a median follow up of 26.4 years to December 2015. It used self-reported smoking habits at baseline to categorise participants as current, former or never smokers and to calculate the years since quitting and pack-years of smoking. Heavy smoking was defined as 20 or more pack-years; 2371 of the participants were defined as heavy smokers (17% former and 83% current smokers).
Although smoking cessation in heavy smokers resulted in significantly reduced CVD risk within five years compared with current heavy smokers, the risk of CVD remained significantly elevated for 10 to 15 and possibly up to 25 years after cessation compared with never smoking.
‘While we need to continue to emphasise the early major benefits to individuals who quit, it is sobering from a population perspective that there will be a significant time lag in reduction of CVD, despite lowering of overall smoking rates,’ Professor Tofler said.
‘Individual smokers should not be lulled into falsely thinking that quitting can be deferred, since these Framingham data show that the added risk of heart attack and stroke cannot be fully reversed rapidly.’
Professor Tofler told Medicine Today that in Australia we have 2.5 million daily smokers and 22,000 deaths annually due to smoking, a large proportion of which is due to CVD and stroke.
‘We need to double all efforts from an individual and population level to stop the uptake of cigarettes in the first place.’
JAMA 2019; 322: 642-650; doi:10.1001/jama.2019.10298.