Socio-economic inequalities in lung cancer incidence in Canada, 1992-2010: results from the Canadian Cancer Registry.

ABSTRACT

OBJECTIVES: Lung cancer is the most commonly diagnosed cancer in Canada. This study aims to assess trends in income and education inequalities in the incidence of lung cancer in Canada. STUDY DESIGN: The study design is a time-trend analysis of nationally collected data. METHODS: Using a linked data set of the Canadian Cancer Registry (CCR) data file, the Canadian Census of Population and National Household Survey, we calculated the incidence of lung cancer in Canada over the period between 1992 and 2010. The age-adjusted concentration index (C), which captures socio-economic inequality across a continuous spectrum of socio-economic status, was used to measure income and education inequalities in the incidence of lung cancer in men and women. RESULTS: The crude incidence rate for men decreased significantly over time in Canada from 85 to 78 per 100,000 population from 1992 to 2010, respectively. For women, the crude incidence rate increased significantly over time in Canada from 45 to 67 per 100,000 population from 1992 to 2010, respectively. The age-adjusted C indicated a higher concentration of lung cancer incidence among low income and less educated Canadians over the study period. Although income inequality in lung cancer incidence decreased significantly over time for men, education inequality increased significantly for both men and women. CONCLUSIONS: Increased occurrence of lung cancer among the poor and less educated populations in Canada remains a challenge in Canada. Income and education gradients in the lung cancer incidence are likely explained by variations in known risk factors especially smoking across socio-economic groups. Continuous efforts are required to reduce the causes of lung cancer among low socio-economic status Canadians.