Life-course body size and perimenopausal mammographic parenchymal patterns in the MRC 1946 British birth cohort

Abstract

Dense mammographic parenchymal patterns are associated with an increased risk of breast cancer. Certain features of body size have been found to be associated with breast cancer risk, but less is known about their relation to breast density. We investigated the association of birth size, childhood growth and life-course changes in body size with Wolfe grade in 1298 perimenopausal women from a British cohort of women born in 1946. The cohort benefits from repeated measures of body size in childhood and adulthood. We obtained mammograms for 90% of women who at age 53 years reported having previously had a mammogram. We found no associations with birth weight or maximum attained height. Body mass index (BMI) at age 53 years and breast size were independently and inversely associated with Wolfe grade (P-value for trend o0.001 for both). Women who reached puberty later were at a greater odds of a higher Wolfe grade than women who had an earlier puberty (odds ratio associated with a 1 year delay in menarche 1.14, 95% CI: 1.01 -1.27, adjusted for BMI and breast size at mammography). A higher BMI at any age during childhood or adult life was associated with a reduction in the odds of a higher Wolfe grade, after controlling for breast size and BMI at mammography, for example, standardised odds ratio for height at age 7 was 0.72 (95% CI: 0.64, 0.81). These findings reveal the importance of taking life-course changes in body size, and not just contemporaneous measures, into account when using mammographic density as an intermediate marker for risk of breast cancer.

Life course breast cancer risk factors and adult breast density (United Kingdom)

“…We found no relationship between birth weight or leg length and density. Previous reports also suggest no relationship between birth weight and mammographic features [18,41]. Our data suggest that the possible effect of leg length on breast cancer risk [42] is not mediated through factors which influence breast density.…”

“…We investigated the use of ordinal logistic regression in the analysis of our ordered categorical outcome (SCC). This approach has previously been used for the analysis of Wolfe patterns [18]. However, for several of the models, the assumption of proportional odds underlying models were violated.…”

“…Firstly, in our study height is measured in young adulthood, prior to any age-related height loss occurring. One study found greater height loss in women with less dense breasts [18], which would result in an association between breast density and height when measured in later life, but not when height in early adulthood is used. Secondly, most cohort members in the current study experienced a relatively high socio-economic position in childhood, and the determinants of height in this cohort may not be the same are those in the general population.…”

Menstrual and reproductive factors in relation to mammographic density: the Study of Women’s Health Across the Nation (SWAN)

“…In addition, little data are available for the association of menstrual and reproductive factors with mammographic density during the very early stages of the menopausal transition [20,21], before its decline with menopause [22]. We evaluated the association between menstrual and reproductive risk factors and mammographic density in a community-based cohort of pre-and early perimenopausal Chinese, Japanese, African-American and non-Hispanic white women in the U.S.…”

Dietary calcium and vitamin D intakes in childhood and throughout adulthood and mammographic density in a British birth cohort

“…Thus, copies of the mammograms (two views for each breast) were taken when the women were closest to the age of 50 years, the prevalent screening round, were requested from the relevant centres. Successfully, we obtained the copies of mammograms for 1319 of the 1471 women who gave consent (90% tracing rate), the large majority (1249 (95%)) from NHS breast screening centres (McCormack et al, 2003). The mammograms were scanned using an Array 2905 laser digitiser with optical density range 0 -4.0, 12-bit depth and pixel size of 75 mm.…”