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

ObjectivesThis 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 MethodsThis was a retrospective cohort study of women participating in the Australian Longitudinal Study on Womens 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). ResultsParticipants 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). ConclusionFindings 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. Key messagesO_LIOverweight and obesity increase risk of breast cancer, poorer prognostic features and worse outcomes. C_LIO_LILong-term impacts on screening participation are evident among higher BMI women who are less likely to participate in routinely organised breast screening. C_LIO_LIThis relationship is stronger among women of lower educational attainment. C_LIO_LIWomen with a higher BMI should be a focus of targeted efforts to improve their breast screening participation C_LI