Adjusting for BMI in analyses of volumetric mammographic density and breast cancer risk.
Breast Cancer Res
; 20(1): 156, 2018 12 29.
Article
en En
| MEDLINE
| ID: mdl-30594212
ABSTRACT
BACKGROUND:
Fully automated assessment of mammographic density (MD), a biomarker of breast cancer risk, is being increasingly performed in screening settings. However, data on body mass index (BMI), a confounder of the MD-risk association, are not routinely collected at screening. We investigated whether the amount of fat in the breast, as captured by the amount of mammographic non-dense tissue seen on the mammographic image, can be used as a proxy for BMI when data on the latter are unavailable.METHODS:
Data from a UK case control study (numbers of cases/controls 414/685) and a Norwegian cohort study (numbers of cases/non-cases 657/61059), both with volumetric MD measurements (dense volume (DV), non-dense volume (NDV) and percent density (%MD)) from screening-age women, were analysed. BMI (self-reported) and NDV were taken as measures of adiposity. Correlations between BMI and NDV, %MD and DV were examined after log-transformation and adjustment for age, menopausal status and parity. Logistic regression models were fitted to the UK study, and Cox regression models to the Norwegian study, to assess associations between MD and breast cancer risk, expressed as odds/hazard ratios per adjusted standard deviation (OPERA). Adjustments were first made for standard risk factors except BMI (minimally adjusted models) and then also for BMI or NDV. OPERA pooled relative risks (RRs) were estimated by fixed-effect models, and between-study heterogeneity was assessed by the I2 statistics.RESULTS:
BMI was positively correlated with NDV (adjusted r = 0.74 in the UK study and r = 0.72 in the Norwegian study) and with DV (r = 0.33 and r = 0.25, respectively). Both %MD and DV were positively associated with breast cancer risk in minimally adjusted models (pooled OPERA RR (95% confidence interval) 1.34 (1.25, 1.43) and 1.46 (1.36, 1.56), respectively; I2 = 0%, P >0.48 for both). Further adjustment for BMI or NDV strengthened the %MD-risk association (1.51 (1.41, 1.61); I2 = 0%, P = 0.33 and 1.51 (1.41, 1.61); I2 = 0%, P = 0.32, respectively). Adjusting for BMI or NDV marginally affected the magnitude of the DV-risk association (1.44 (1.34, 1.54); I2 = 0%, P = 0.87 and 1.49 (1.40, 1.60); I2 = 0%, P = 0.36, respectively).CONCLUSIONS:
When volumetric MD-breast cancer risk associations are investigated, NDV can be used as a measure of adiposity when BMI data are unavailable.Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Procesamiento de Imagen Asistido por Computador
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Neoplasias de la Mama
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Mamografía
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Índice de Masa Corporal
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Densidad de la Mama
Tipo de estudio:
Etiology_studies
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Incidence_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
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Screening_studies
Límite:
Aged
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Aged80
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Female
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Humans
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Middle aged
País/Región como asunto:
Europa
Idioma:
En
Revista:
Breast Cancer Res
Asunto de la revista:
NEOPLASIAS
Año:
2018
Tipo del documento:
Article
País de afiliación:
Reino Unido