title: Coffee and black tea consumption and breast cancer mortality in a cohort of Swedish women.
abstract: BACKGROUND
  Coffee and black tea contain a mixture of compounds that have the potential to influence breast cancer risk and survival. However, epidemiologic data on the relation between coffee and black tea consumption and breast cancer survival are sparse.
  
  
  METHODS
  We investigated the association between coffee and black tea consumption and survival among 3243 women with invasive breast cancer in the Swedish Mammography Cohort. Intake was estimated using a food frequency questionnaire. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs).
  
  
  RESULTS
  From 1987 to 2010 there were 394 breast cancer-specific deaths and 973 total deaths. Coffee and black tea were not associated with breast cancer-specific or overall mortality. Women consuming 4+ cups of coffee per day had a covariate and clinical characteristics-adjusted HR (95% CI) of death from breast cancer of 1.14 (0.71-1.83; p(trend)=0.81) compared with those consuming <1 cup per day. Women consuming 2+ cups of black tea per day had a covariate and clinical characteristics-adjusted HR (95% CI) of death from breast cancer of 1.02 (0.67-1.55; p(trend)=0.94) compared with non-tea drinkers. Caffeine was also not associated with breast cancer-specific (HR for top to bottom quartile=1.06; 95% CI=0.79-1.44; p(trend)=0.71) or overall mortality.
  
  
  CONCLUSIONS
  Our findings suggest that coffee, black tea, and caffeine consumption before breast cancer diagnosis do not influence breast cancer-specific and overall survival.
authors: Division of Nutritional Epidemiology, The National Institute for Environmental Medicine, Karolinska Institutet, PO Box 210, Stockholm 171 77, Sweden. holly.harris@ki.se
authors: H R
authors: HR
authors: Harris
authors: L
authors: L
authors: Bergkvist
authors: A
authors: A
authors: Wolk
mesh_terms: D000368:Aged; D001628:Beverages / Q000706:statistics & numerical data*; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology; D002110:Caffeine / Q000008:administration & dosage; D003069:Coffee; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D015996:Survival Rate; D013548:Sweden / Q000453:epidemiology; D013662:Tea
chemical_list: D003069:Coffee; D013662:Tea; D002110:Caffeine