The risk of premature death is maintained for heavy smokers who reduce by more than half their consumption

The risk of premature death, including cancer and cardiovascular diseases remains high among former heavy smokers, even after 30 years have reduced by more than half their tobacco consumption, suggests a Norwegian study published in the journal "Tobacco Control".
While many studies have shown the benefits of smoking cessation, only a large prospective study evaluated the long-term effects of reduced consumption, Aage Tverdal reminiscent of the Norwegian Institute of Public Health in Oslo and Kjell Bjartveit National Health Service analysis in Oslo.

The researchers examined whether the health risks of heavy smokers decreased when reducing their consumption by at least half. To do this, they used data from more than 50,000 Norwegians who participated in the 1970s to a large study on cardiovascular risk and were followed until 2003, with an interim evaluation.

The researchers divided the participants into six categories: those who had never smoked, those who had stopped before inclusion, those who stopped smoking between baseline and the last assessment, moderate smokers (14 cigarettes a per day), while the long heavy smokers more than 15 cigarettes per day reduced their consumption by more than half (on average, 58% of men and 56% women) and heavy smokers of study.

Data on cumulative death show that mortality among those who reduced their smoking decreased slightly compared to heavy smokers during the first 15 years of follow up, then catch up. For women, the mortality rate was even higher among those who had reduced compared with those who had kept a big tobacco.

The adjusted analysis of the data shows that for both sexes, the risk of death from all causes is equivalent after 30 years in heavy smokers who reduced their smoking by more than half compared with those who maintained their consumption. The results are similar for cardiovascular death, only by ischemic heart diseases, cancers associated with smoking and lung cancer in particular.

Gender analysis does not appear to benefit from a reduction of smoking, regardless of the cause of death.

The results show that gender However, mortality is reduced for all other participants compared to heavy smokers. The risk of death is the lowest observed for people who have never smoked, reduced overall by 66%, and for those who had stopped smoking at baseline, with a decrease of 63%. The risk of death was reduced by 53% for those arrested during the study and 24% in moderate smokers.

This study shows "clear" that the only way to get rid of the risks of smoking is to quit smoking and suggests that it should review the advice to reduce consumption in the absence of a total withdrawal, the researchers conclude.