Morbidity as a Predictor for Participation in the Danish National Mammography Screening Program: A Cross-Sectional Study

Purpose: In this cross-sectional study, we evaluated the association between morbidity and participation in the prevalence round of the Danish national mammography screening program. Patients and Methods: Morbidity was assessed by the Charlson Comorbidity Index (CCI) score (0, 1-2, and >= 3) and by 19 individual diagnoses. We retrieved data on participation from The Danish Quality Database of Mammography Screening and on diagnoses from The Danish National Patient Registry. We estimated prevalence proportion ratios (PR) with 95% confidence intervals (CI). Results: In total, 519,009 (79.8%) women participated in the first national breast cancer screening round. Relative to women with a CCI score of 0, the adjusted PRs were 0.96 (95% CI: 0.95-0.96) for a CCI score of 1-2 and 0.80 (95% CI: 0.79-0.81) for a CCI score of >= 3. Compared with no disease, the PRs for a diagnosis of the most prevalent, but less severe diseases, chronic pulmonary disease, cerebrovascular disease, diabetes I and II were 0.93 (95% CI: 0.93-0.94), 0.96 (95% CI: 0.94-0.96), and 0.96 (95% CI: 0.95-0.97), respectively. Among women with low prevalent, but most severe diseases, the PRs were 0.69 (95% CI: 0.60-0.81) for AIDS and 0.73 (95% CI: 0.70-0.76) for metastatic solid tumor. Conclusion: Women with a high CCI score or one severe chronic condition are less likely to participate in breast cancer screening compared to women without disease. However, these women account for a small proportion of all non-participating women. Thus, it might be most beneficial to maximize breast cancer screening participation in women with less severe although more common morbidities.