Smoking just one cigarette a day can yo the risk of developing coronary heart disease and stroke, reveals a new study published in the British Medical Journal.
Researchers from Cancer Research UK, UCL Cancer Trials Centre and the University of London along with those from the Chinese University of Hongkong conducted a meta analysis of 55 publications containing 141 cohort studies. The risks were found to be higher for women than for men. Among men the relative risk for coronary heart disease was 1.48 for smoking one cigarette per day and 2.04 for 20 cigarettes per day. For women the relative risks were 1.57 and 2.84 for one and 20 cigarettes per day.
The study concluded: “Smoking only about one cigarette per day carries a risk of developing coronary heart disease and stroke much greater than expected: around half that for people who smoke 20 per day. No safe level of smoking exists for cardiovascular disease. Smokers should aim to quit instead of cutting down to significantly reduce their risk of these two common major disorders.”
In other words, the study found that men who smoked one cigarette a day had 45% excess risk of heart disease and 41% excess risk of stroke associated with smoking 20 cigarettes a day, relative to non-smokers. That such a low level of smoking carries unexpectedly high risks will surprise many people, says BMJ editorialist Kenneth Johnson: “Only complete cessation is protective and should be emphasised by all prevention measures.”
Around one billion adults worldwide smoke with high prevalence in developing countries where 49% men and 11% women use tobacco. In India according to the Global Adult Tobacco Survey factsheet, 19% men, 2% women and 10.7% of all adults smoke tobacco.