['To study the relationship between exposure to antibiotic treatment and risk of subsequent myocardial infarction (MI) in patients with diabetes.', 'A case-control design was used to assess the effect of previous antibiotic exposure in diabetes patients with acute, nonfatal or fatal MI (case subjects) and individually matched control subjects (four control subjects to one case subject, matched on sex, age, and index date). Subjects were sampled from the Northern California Kaiser Permanente Diabetes Registry, a well-characterized, ethnically diverse diabetic population from Kaiser Permanente Medical Care Program, Northern California Region. MI events were ascertained during a 2-year observation period (1998-1999). Separate conditional logistic regression models were specified to assess antibiotic exposure history (cephalosporins only, penicillins only, macrolides only, quinolones only, sulfonamides only, tetracyclines only, as well as more than one, any, or no antibiotic) for three nested windows before the index date (0-6 months, 0-12 months, 0-24 months), facilitating assessment of whether the potential effect was dependent on the timing of the exposure.', 'A total of 1,401 MI case subjects were observed. Odds ratios were calculated in models adjusted for age, sex, race, education attainment, time since diabetes diagnosis, diabetes type and treatment, use of diet and exercise, total cholesterol, HDL cholesterol, triglyceride levels, hypertension, elevated urinary albumin excretion, serum creatinine, BMI, and smoking. We found no evidence of a protective effect of any of these therapeutic classes of antibiotics during any of the three time frames.'] Is use of antibiotics associated with decreased risk of myocardial infarction among patients with diabetes?