The longitudinal role of overweight and obesity women in mammographic breast screening participation: retrospective cohort study using linked data

Objectives: This study investigated the association between prospective changes in BMI and longitudinal adherence to mammographic screening among overweight or obese women residing in New South Wales, Australia Methods: This was a retrospective cohort study of women participating in the Australian Longitudinal Study on Women's Health (ALSWH), with subsequent screening participation enumerated via BreastScreen New South Wales, Australia clinical records over the period 1996-2016. The association between BMI and subsequent adherence to screening was investigated in a series of marginal structural models, incorporating a range of socio-demographic, clinical, and health behaviour confounders. Models were also stratified by proxy measures of socio-economic status (private health insurance and educational achievement). Results: Participants who had overweight/obesity were more likely to be non-adherent to mammography screening, compared to normal or underweight participants (OR=1.29, [95% CI=1.07, 1.55). The association between overweight/obesity and non-adherence was slighter stronger among those who ever had private health insurance (OR=1.30, [95% CI=1.05, 1.61) compared to those who never had private health insurance (OR=1.19, [95% CI=0.83, 1.71), and among those with lower educational background (OR=1.38, [95% CI=1.08, 1.75) compared to those with higher educational background (OR=1.27, [95% CI=0.93, 1.73). Conclusion: Findings show long-term impacts on screening participation with higher BMI women being less likely to participate in routinely organised breast screening. Women with a higher BMI should be a focus of efforts to improve breast screening participation, particularly given their increased risk of post-menopausal breast cancer and the association of higher BMI with more aggressive clinical presentations and histopathology of breast cancers. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by a Western Sydney University Women's Fellowship ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The New South Wales Population & Health Services Research Ethics Committee of the New South Wales Government gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript