Oral Presentation 2025 Joint Meeting of the COSA ASM and IPOS Congress

Socioeconomic differences in the distribution of smoking-related cancer burden in Australia (126181)

Maarit A Laaksonen 1 2 , Claire M Vajdic 2 , Karen Canfell 1 , Robert J MacInnis 3 , Emily Banks 4 , Paul Mitchell 1 , Julie E Byles 5 , Dianna J Magliano 6 , Jonathan E Shaw 6 , Tiffany K Gill 7 , Vasant Hirani 1
  1. University of Sydney, Sydney
  2. University of New South Wales, Sydney
  3. Cancer Council Victoria, Melbourne
  4. Australian National University, Canberra
  5. University of Newcastle, Newcastle
  6. Baker IDI Heart and Diabetes Institute, Melbourne
  7. University of Adelaide, Adelaide

Objectives: Although more disadvantaged socioeconomic groups generally have higher smoking prevalence and incidence of smoking-related cancers than less disadvantaged groups, socioeconomic differences in the smoking-related cancer burden have not been quantified.

Sample and setting: We linked pooled individual-level data from seven Australian cohort studies (N=367,058) to national population-based cancer and death registries.

Procedures: We quantified the smoking-cancer association by area-based socioeconomic status (SES) using proportional hazards modelling, adjusting for age, sex, alcohol consumption, BMI, height, and study. We estimated current and past adult smoking prevalence by SES from the Australian National Health Survey 2022, and combined these estimates to calculate the population attributable fraction (PAF) of smoking-related cancers attributable to smoking for each SES quintile, accounting for competing risk of death. We also calculated 95% confidence intervals for differences in PAF estimates between SES quintiles.

Results: Overall, 28% (95%CI 26-30%) of smoking-related cancers in Australia are attributable to smoking. The smoking-attributable cancer burden varies by SES quintile: 1 (most-disadvantaged) to 5 (least-disadvantaged) = 39%, 32%, 29%, 22%, and 18%, respectively. The smoking-related cancer burden in the three lowest SES quintiles is significantly higher than in the two highest SES quintiles (p-values from <0.001 to 0.026). The burden in the most-disadvantaged group (39%) is more than double that of the least-disadvantaged group (18%). These differences are driven mainly by differences in smoking prevalence, with three times as many people currently smoking in the most-disadvantaged (18%) compared with the least-disadvantaged SES quintile (5%).

Conclusions and clinical implications: Smoking-related cancer burden varies substantially by SES, with the most-disadvantaged group experiencing twice the burden of the least-disadvantaged. Understanding the complex reasons behind higher smoking prevalence and smoking-attributable cancer burden in disadvantaged groups is crucial for effective intervention. Accelerated whole-of-population and priority population tobacco control is warranted, including that targeting those most in need.