Europeans with the lowest educational level have two to three times more risk for developing lung cancer than others. Smoking accounts for approximately half of this increased risk. Researchers at University Medical Center Utrecht (UMC) and the National Institute for Public Health and the Environment (RIVM) describe their findings, together with international colleagues in the Journal of the National Cancer Institute, published on February 24, 2009.
In the EPIC-study, almost 400,000 Europeans were asked about their education, their smoking and other lifestyle habits and then followed-up for about 8.5 years. After this period of follow-up, about 1,700 people had developed lung cancer. It was shown that men with the least education had a 3.6 higher risk of developing lung cancer than men with the highest educational level. For women with the least education, the risk factor was 2.4 times higher. Smoking accounted for approximately half of this excess risk whilst diet could not account for any of the difference. Approximately 40,000 people from the Netherlands took part in the study.
Previous studies have shown that people with a lower socioeconomic status have a higher risk of lung cancer and that this can be partially blamed on differences in smoking habits. Now researchers have calculated how much of the difference in lung cancer incidence in people with the least and highest education can be explained by smoking habits. Each year about nine thousand people die as a result of lung cancer in the Netherlands.
Clinical epidemiologist professor Petra Peeters of UMC Utrecht was involved in the study which was led by Dr. Bas Bueno de Mesquita of the RIVM. They think that prevention and education should focus particularly on lower-educated people because of the social inequality regarding the distribution of lung cancer among the population.
According to Bueno de Mesquita, the effect of smoking is probably a little higher than the fifty percent that was found in this study. “Participants have most likely not written down their actual smoking behavior accurately. Moreover, we do not know, for example, how many people smoke passively - and that is something that also increases the risk of lung cancer.”
However, smoking does not conclusively explain why lung cancer occurs in lower educated people. Considering that diet did not provide an explanation, the authors have suggested that work-related exposure to harmful substances could possibly be a contributory factor for the difference.