Pre-diagnostic breastfeeding, adiposity and mortality among parous Hispanic and non-Hispanic white women with invasive breast cancer: the Breast Cancer Health Disparities Study
Published Date:Nov 11 2016
Source:Breast Cancer Res Treat. 161(2):321-331.
Pubmed Central ID:PMC5226868
Funding:R01 CA078552/CA/NCI NIH HHS/United States
HHSN261201000036C/CA/NCI NIH HHS/United States
R01 CA078762/CA/NCI NIH HHS/United States
U58 DP000807/DP/NCCDPHP CDC HHS/United States
R01 CA078802/CA/NCI NIH HHS/United States
R01 CA078682/CA/NCI NIH HHS/United States
R01 CA140002/CA/NCI NIH HHS/United States
R01 CA063446/CA/NCI NIH HHS/United States
U.S. Hispanic women have high rates of parity, breastfeeding and obesity. It is unclear whether these reproductive factors are associated with breast cancer (BC) mortality. We examined the associations between breastfeeding, parity, adiposity and BC-specific and overall mortality in Hispanic and non-Hispanic white (NHW) BC cases.
The study population included 2,921 parous women (1,477 Hispanics, 1,444 NHWs) from the Breast Cancer Health Disparities Study with invasive BC diagnosed between 1995 and 2004. Information on reproductive history and lifestyle factors was collected by in-person interview. Overall and stratified Cox proportional hazard regression models by ethnicity, parity, and body mass index (BMI) at age 30 years were used to calculate hazard ratios (HR) and 95% confidence intervals (CI).
After a median follow-up time of 11.2 years, a total of 679 deaths occurred. Pre-diagnostic breastfeeding was associated with a 16% reduction in mortality (HR, 0.84; 95% 0.72-0.99) irrespective of ethnicity. Parity significantly modified the association between breastfeeding duration and mortality (p-interaction= 0.05), with longer breastfeeding duration associated with lower risk among women who had ≤ 2 births (p-trend= 0.02). Breastfeeding duration was associated with reduced risk of both BC-specific and overall mortality among women with BMI < 25 kg/m2, while positive associations were observed among women with BMI ≥ 25 kg/m2 (p-interactions < 0.01).
Pre-diagnostic breastfeeding was inversely associated with risk of mortality after BC, particularly in women of low parity or normal BMI. These results provide another reason to encourage breastfeeding and weight management among young women.
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