“Smoking Kills” is more than just a catchy PSA or quit smoking campaign slogan – it’s a verifiable fact. Since the mid-20th century, study after study has provided compelling evidence that smoking is associated with increased mortality rates. Arguably the most influential of these is the 1956 publication of smoking data on the British Doctors Study, which provided compelling evidence that more than half of smokers would eventually die from smoking-related complications. A new study published in BMC Medicine claims that this death rate could be as high as 66 percent, meaning that two out of three smokers will eventually die from conditions related to their smoking.
This study, compiled by researchers at the National Center for Epidemiology and Population Health at the Australian National University, followed 204,953 men and women over the age of 45 from New South Wales, Australia. These participants were divided into groups of smokers, former smokers and never smokers.
The researchers found that the percentage of smokers was similar between men and women. They also found that current smokers are more likely to be younger than never smokers, and less likely to live in urban areas. Current smokers had lower incomes and education compared to never smokers, and they were less likely to have private health insurance. Finally, current smokers were more likely to report consuming more than 15 alcoholic beverages per week and were more likely to have a higher body mass index.
(These factors were taken into account when mortality statistics were examined.)
Person-years are a measure of time used in epidemiological studies, where the researched years of all participants in a study are added together. For example, if three people were studied for 10 years each, a total of 30 person-years would be reported in the study. The study published in BMC Medicine examined a total of 874,120 person-years, and 5,593 deaths occurred in the study population during those person-years.
Epidemiological outcomes are usually reported in terms of “Relative risk,” which describes the proportion of the risk of an outcome that can be attributed to a specific factor. In this study, the relative risk of death (known as mortality) for male and female smokers showed that they were approximately 2.76 and 2.95 times more likely to die than never smokers. Quitting helps; male and female former smokers were 1.27 and 1.39 times more likely to die than never smokers. While these numbers are not surprising given the large amount of data on the risks of smoking, they are nevertheless a staggering reminder of the quantifiable risks of smoking.
The researchers also looked at the death rate in relation to the number of cigarettes smoked per day. They found that there was a twofold increase in mortality for participants who smoked 1-14 cigarettes per day and a fourfold increase in mortality for those who smoked more than 25 cigarettes per day (compared to never smokers).
This study does report the promising finding that smoking cessation, even later in life, can significantly reduce the risk of smoking-related death, a finding that has been demonstrated several times in the smoking literature. The researchers found that when they compared participants who had quit smoking between the ages of 45-54, the relative risk of dying for men and women was only 1.36 or 1.52 times the risk of dying in never smokers. . They found that the risk of death gradually decreased, and this was proportional to the amount of time that had passed since the participant stopped smoking.
While the findings of this study are very similar to smoking studies conducted in the US and UK, this is the first large-scale population study conducted in Australia to show that the risks of smoking transcend cultural lifestyle factors. Moreover, despite the fact that this finding is similar to the existing literature on the risks of smoking, these striking data on the nearly three-fold increase in the death rate for smokers remain relevant, as many people seem to ignore that message or never fully realize it. conscience. .
The good news is that it’s not too late to quit smoking to improve your future health.
BMC medicine2015. DOI: 10.1186/s12916-015-0281-z (About DOIs).