By Imogen Howse via SWNS
Lung cancer rates are not dropping as quickly as expected as people quit smoking, a new study has revealed.
The number of smokers has decreased rapidly over the past few decades, yet lung cancer cases are as common in 2021 as they were in 1970 despite far fewer people smoking.
Researchers say that the results might be because the effects of smoking even after quitting are much longer than currently thought.
The team from Umeå University in Sweden compared smoking habit changes with lung cancer incidence between 1970 and 2021, among men and women between the ages of 40 and 84.
Results, published in the European Journal of Public Health, also showed how rates differed dramatically for men and women.
For women between the ages of 75 and 79, the risk of squamous cell cancer has increased – but for men, this type of cancer has fallen and been replaced with another type, adenocarcinoma, which has increased sixfold.
Overall, lung cancer rates for women have increased since 1970, but rates for men have dropped.
This has been linked to women generally starting smoking later in history than men.
Professor Bengt Järvholm said: “Smoking is undoubtedly the most important risk factor for lung cancer.
“It is therefore surprising that the decline in smoking is not yet more visible in the statistics.”
He said there could be various reasons for this – including people underreporting their smoking.
“The study does not provide an answer as to why the development of lung cancer does not correspond with expectations, but there are several possible explanations,” Järvholm said.
“One explanation may be that people may underreport their smoking, i.e., that the reduction in smoking is smaller in reality than it is on paper.
“Another possible explanation may be that previous assumptions about how quickly the risk of being affected decreases when you quit smoking have been exaggerated.
“We may therefore have to change our view on how long smoking affects your health.”
Järvholm added that lifestyle or environmental factors also have to be considered – such as exposure to pollution or chemicals.
“Even those who have never smoked can get lung cancer, although it is less common,” he said.
The study encourages people to still try to quit smoking – saying the findings do not negate the benefits.
“The results should certainly not be interpreted as saying it is useless to quit smoking,” Järvholm explained.
“On the contrary, the study emphasizes the importance of quitting early, preferably never starting, as it may be the case that the risk of lung cancer is elevated for longer than we previously thought.”
