That smoking is harmful to a person’s health in the short and long term is hardly a surprise to anyone today and we have previously reported how this may be particularly harmful to women. Until recently the reports of the long-term benefits of cessation remained scarce. Now, a large-scale study that has been published in The Lancet suggests that for women, the benefits of quitting smoking are substantial if it occurs before the age of 30.
The study, which goes by the name The Million Woman Study, was led by Professor Richard Peto of Oxford University. In total 1.3 million women from the UK were recruited between 1996 and 2001. Of those, 0.1 million cases were excluded on the basis that they had presented with a history of heart disease, stroke or had a current respiratory treatment. The participants were followed up with a postal survey three and eight years after entering the study. The key aspects considered included socio-demographic data, medical history and questions related to lifestyle. The participants that did not respond to the survey were still followed up via NHS records. Overall, the average follow-up was 12 years. The key findings indicated that women who stopped smoking before the age of 30 were able to eradicate 97% of all the risks of premature death that were associated with tobacco-related illnesses. Moreover, in women who stopped before the age of 40 this figure reached 90%. This led the team to suggest that stopping smoking, preferably before the age of 30, is to be recommended.
Although the findings may not sound novel, several aspects of the study are particularly noteworthy. In addition to having a large sample, the sample also stands out by being of a mature age. This of course, enabled the researchers to consider the life-long effects of smoking which has not been possible until recently as the increase of female smokers occurred in the 1950s and the 1960s. The study also benefitted from adjusting for socio-demographic factors, which have often been a concern in previous studies. It is also worth mentioning that these findings corroborate recent smaller studies from both the US and Japan and appear to be applicable to many other countries.
Although the findings are remarkable, it is important to have a nuanced interpretation of the implication of the results. Naturally, the findings are a cause for optimism, but they do not imply that smoking before the age of 30 does not cause any harm to a person’s body. In the report it was noted that the age at which a person starts to smoke affected mortality rates decades later and that the risks associated with smoking increase in a dose-response fashion. Therefore, it would be unreasonable to expect that cessation before the age of 30 instantly eradicates all the effects smoking has done up until that stage.
Although we are not surprised by the findings, we do find it refreshing that the report emphasizes the benefits of cessation rather than purely focusing on the harmful effects associated with prolonged smoking.