Use of antibiotics and risk of breast cancer.
American Journal of Epidemiology. 2005;161(7):616-619
ABSTRACT
A recent nested case control study found that increasing use of antibiotics was associated with a significant elevated risk of breast cancer. The authors attempted to replicate this finding with a similar study design using the General Practice Research Database in the United Kingdom. Women 30-79 years old registered in the database between January 1995 and December 2001 comprised the study cohort. A total of 3,708 incident cases of breast cancer and 20,000 frequency-matched controls were used in a nested case-control analysis. Use of antibiotics was not associated with an increased risk of breast cancer. For categories of increasing cumulative days of use (1-50, 51-100, 101-500, and ≥501 days), the corresponding odds ratios (95% confidence interval) were 1.0 (0.9,1.1), 1.0 (0.8,1.1), 0.9 (0.7,1.0), and 1.2 (0.9,1.6) (p=0.31 for trend). Based on the results of this study, antibiotic use does not appear to be a major determinant of breast cancer risk.