Adult weight gain, fat distribution and mammographic density in Spanish pre- and post-menopausal women (DDM-Spain).
High mammographic density (MD) is a phenotype risk marker for breast cancer. Body mass index (BMI) is inversely associated with MD, with the breast being a fat storage site. We investigated the influence of abdominal fat distribution and adult weight gain on MD, taking age, BMI and other confounders into account. Because visceral adiposity and BMI are associated with breast cancer only after menopause, differences in pre- and post-menopausal women were also explored. We recruited 3,584 women aged 45-68 years within the Spanish breast cancer screening network. Demographic, reproductive, family and personal history data were collected by purpose-trained staff, who measured current weight, height, waist and hip circumferences under the same protocol and with the same tools. MD was assessed in the left craniocaudal view using Boyd's Semiquantitative Scale. Association between waist-to-hip ratio, adult weight gain (difference between current weight and self-reported weight at 18 years) and MD was quantified by ordinal logistic regression, with random center-specific intercepts. Models were adjusted for age, BMI, breast size, time since menopause, parity, family history of breast cancer and hormonal replacement therapy use. Natural splines were used to describe the shape of the relationship between these two variables and MD. Waist-to-hip ratio was inversely associated with MD, and the effect was more pronounced in pre-menopausal (OR = 0.53 per 0.1 units; 95 % CI = 0.42-0.66) than in post-menopausal women (OR = 0.73; 95 % CI = 0.65-0.82) (P of heterogeneity = 0.010). In contrast, adult weight gain displayed a positive association with MD, which was similar in both groups (OR = 1.17 per 6 kg; 95 % CI = 1.11-1.23). Women who had gained more than 24 kg displayed higher MD (OR = 2.05; 95 % CI = 1.53-2.73). MD was also evaluated using Wolfe's and Tabár's classifications, with similar results being obtained. Once BMI, fat distribution and other confounders were considered, our results showed a clear dose-response gradient between the number of kg gained during adulthood and the proportion of dense tissue in the breast.
Cancer Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Monforte de Lemos 5, 28029 Madrid, Spain. mpollan@isciii.es
Marina
M
Pollán
Virginia
V
Lope
Josefa
J
Miranda-García
Milagros
M
García
Francisco
F
Casanova
Carmen
C
Sánchez-Contador
Carmen
C
Santamariña
Pilar
P
Moreo
Carmen
C
Vidal
Mercé
M
Peris
María Pilar
MP
Moreno
José Antonio
JA
Vázquez-Carrete
Francisca
F
Collado
Carmen
C
Pedraz-Pingarrón
Nieves
N
Ascunce
Dolores
D
Salas-Trejo
Nuria
N
Aragonés
Beatriz
B
Pérez-Gómez
Francisco
F
Ruiz-Perales
D050153:Abdominal Fat / Q000473:pathology*; D050154:Adiposity; D000368:Aged; D050218:Body Fat Distribution; D015992:Body Mass Index; D001940:Breast / Q000473:pathology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008327:Mammography; D008403:Mass Screening; D008875:Middle Aged; D016017:Odds Ratio; D017698:Postmenopause; D017697:Premenopause; D012307:Risk Factors; D013030:Spain; D013046:Specific Gravity; D011795:Surveys and Questionnaires; D049629:Waist-Hip Ratio; D015430:Weight Gain