Widening socioeconomic disparity in lung cancer incidence among men in New South Wales, Australia, 1987-2011

Abstract

OBJECTIVE: We assessed the trends in lung cancer incidence over a 25-year period by socioeconomic groups for men in New South Wales (NSW), Australia. METHODS: Men diagnosed with lung cancer between 1987 and 2011 were divided into five quintiles according to an Index of Education and Occupation (IEO). We assessed relative socioeconomic differences over time by calculating age-standardized incidence ratios (SIRs) by 5-year period of diagnosis, and estimated absolute differences by comparing the observed and expected numbers of cases using the highest IEO quintile as the reference. RESULTS: Lung cancer incidence for men decreased from 1987 to 2011 for all IEO quintiles, with a greater rate of decline for men living in the highest IEO areas. Thus, the relative disparity increased significantly over the 25-year period (P=0.0006). For example, the SIR for the lowest IEO quintile increased from 1.28 during 1987-1991 to 1.74 during 2007-2011. Absolute differences also increased with the proportion of " potentially preventable" cases doubling from 14.5% in 1987-1991 to 30.2% in 2007-2011. CONCLUSIONS: Despite the overall decline in lung cancer incidence among men in NSW over the past 25 years, there was a significant increase in disparity across socioeconomic areas in both relative and absolute terms.