IARC 60th Anniversary - 19-21 May 2026
Session : 20/05/26 - Posters
Social variation in cancer incidence, results from the updated Nordic Occupational Cancer study
MARTINSEN J. 1, LAPPI-HEIKKINEN S. 2, HANSEN J. 3, LYNGE E. 4, TORFADÓTTIR J. 5, MEHLUM I. 6,7, SELANDER J. 8, PUKKALA E. 2,9, WOJEWODZIC M. 1
1 Cancer Registry of Norway/Norwegian Institute of Public Health, Oslo, Norway; 2 Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Helsinki, Finland; 3 Danish Cancer Society Research Center, Copenhagen, Denmark; 4 Nykøbing Falster Hospital, University of Copenhagen, Copenhagen, Denmark; 5 Centre of Public Health Sciences, Faculty of Medicine, University of Iceland, Reykjavik, Iceland; 6 National Institute of Occupational Health (STAMI), Oslo, Norway , Oslo, Norway; 7 Institute of Health and Society, University of Oslo, Oslo, Norway; 8 Institute of Environmental Medicine, IMM Karolinska Institutet, Stockholm, Sweden; 9 Health Sciences Unit, Faculty of Social Sciences, Tampere University, Tampere, Finland
Background
The updated Nordic Occupational Cancer (NOCCA) study includes extended follow-up through 2020, additional birth cohorts, and new occupational categories, covering approximately 21 million individuals and 4.5 million cancer cases. The included 60 occupational categories can also be classified by socioeconomic position (SEP), a key determinant of cancer burden. Lower SEP is associated with higher risks of smoking-related cancers and cervical cancer, whereas melanoma occurs more frequently in higher SEP groups, likely reflecting differences in lifestyle and health-related behaviors.
Objective:
NOCCA quantified socioeconomic disparities in cancer burden for lung cancer in men, cervical cancer, and melanoma in both sexes.
Methods and analysis:
The NOCCA study provides comprehensive, population-based occupational data spanning several decades, enabling detailed investigation of the association between SEP and cancer incidence. By linking occupational histories with long-term cancer registry data, NOCCA allows evaluation of cancer risk across socioeconomic and occupational groups, as well as comparisons over time and between Nordic countries. Cancer risk was estimated using standardized incidence ratios (SIRs), calculated as the ratio of observed to expected cases based on incidence rates in the Nordic populations.
Results:
SIR for lung cancer ranged from 0.89 in the highest SEP-group to 1.15 in the lowest. For cervical cancer, the SIR varied from 0.79 in the highest SEP group to 1.24 in the lowest. In contrast, melanoma showed higher risk in the highest SEP group, with SIRs ranging from 0.82 to 1.28.
Conclusion:
Lung cancer exhibited a clear socioeconomic gradient, with higher risk in lower SEP groups. The risk of cervical cancer decreased with increasing SEP, likely reflecting inequalities in prevention, early detection, and exposure to risk factors. In contrast, melanoma was more common in higher SEP groups, possibly reflecting greater ultraviolet exposure. Together, these findings underscore the important role of SEP in shaping cancer risk.