Body Size and the Risk of Postmenopausal Breast Cancer Subtypes in the California Teachers Study Cohort
Published Date:Jan 28 2012
Source:Cancer Causes Control. .
Pubmed Central ID:PMC3366039
Funding:HHSN261201000035C/CA/NCI NIH HHS/United States
HHSN261201000036C/CA/NCI NIH HHS/United States
R01 CA077398-13/CA/NCI NIH HHS/United States
U58 DP000807/DP/NCCDPHP CDC HHS/United States
HHSN261201000035I/CA/NCI NIH HHS/United States
R01 CA077398/CA/NCI NIH HHS/United States
HHSN261201000034C/CA/NCI NIH HHS/United States
To evaluate how the association between body size and breast cancer risk varies by tumor receptor subtype, host factors and other exposures among women in the California Teacher Study cohort.
Among 52,642 postmenopausal women, 2,321 developed invasive breast cancer with known estrogen- and progesterone-receptor status (1,652 ER+PR+, 338 ER+PR−, 312 ER−PR−) between 1995 and 2007. In a subset of 35,529 with waist circumference data, 1,377 developed invasive breast cancer with known ERPR status (991 ER+PR+, 208 ER+PR−, 169 ER−PR−) between 1997 and 2007. Multivariate Cox regression was performed to estimate relative risks (RR) and 95% confidence intervals (CI).
Obesity, adult weight gain of ≥40 pounds, greater abdominal adiposity and greater height increased risk of ER+PR+ breast cancer. The increased risk associated with postmenopausal obesity was limited to those who did not use hormone therapy (HT) at cohort entry (RR=1.37, 95% CI: 1.05–1.78 for BMI ≥30 vs. <25 kg/m2; P-interaction=0.14) and those who were not overweight or obese at age 18 (P-interaction=0.06). The increased risk associated with greater abdominal adiposity was limited to those who were not also overweight or obese (P-interaction=0.01). Neither obesity, abdominal adiposity nor height were associated with the risk of ER−PR− tumors.
The effects of body size on postmenopausal breast cancer risk differed by hormone receptor subtype, and among women with ER+PR+ tumors, by HT use and early adult body size.
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