Background: The epidemiology of Sudden Cardiac Death (SCD) in women is less clear because women are underrepresented in most studies compared to men. Alcohol and caffeine intake may play a role in the development of SCD due to their effects on cholesterol, hemodynamics, inflammation, and endothelial function. Methods: We examined 93,676 postmenopausal women who participated in the Women's Health Initiative observational study. Women were recruited at 40 clinical sites across the U.S., enrolled between 1993 and 1998, and followed until August 2009. Women completed a food frequency questionnaire at baseline and year 3 that measured total caffeine, total alcohol, wine, liquor, and beer intake. Cups of coffee and tea per day were reported on a separate baseline questionnaire, as well as never and former drinking status. SCD was defined as death occurring within one hour of symptom onset or within one hour after the participant was last seen without symptoms. We modeled exposure to alcohol three ways: using baseline intake only, using a cumulative average of baseline and year 3 intake, and using most recent reported intake (a simple time-varying analysis). Results: 5-10 g per day of alcohol was associated with a reduced risk of SCD compared to 0.1- 5 g per day for all three analytic models (see Table 1 ). The HR's and 95% CI's for SCD were 0.72 (0.47-1.09), 0.98 (0.64-1.50), 0.96 (0.61-1.51), and 1.05 (0.66-1.65) for quintiles 2, 3, 4, and 5 compared to the lowest quintile of total caffeine intake (mg/day). Results were similarly null for cups of caffeinated coffee, decaffeinated coffee, and decaffeinated tea per day. Conclusions: Our results suggest that light alcohol intake (one small drink a day) is associated with a reduced risk of SCD in this population. The results were robust to different exposure models and adjustment methods. Total caffeine, regular coffee, decaffeinated coffee, and regular tea intake were not associated with risk of SCD. Table 1. Hazard Ratio''s for SCD according to alcohol intake using three exposure models. Range # Cases P-yrs Model 1 Model 2 HR 95% CI HR 95% CI TOTAL ALCOHOL (g/day) Exposure model 1: Baseline alcohol intake Never drinker 8 14824 1.78 (0.87-3.62) 1.85 (0.86-3.98) Former drinker 11 34921 1.15 (0.62-2.11) 0.92 (0.47-1.81) 0.1-5g 165 607107 1.0 (ref) 1.0 (ref) 5.1-10g 16 111486 0.54 (0.32-0.90) 0.64 (0.38-1.10) 10.1-30g 26 136616 0.70 (0.46-1.06) 0.86 (0.55-1.32) > 30g 11 41998 0.94 (0.51-1.73) 0.83 (0.42-1.64) Exposure model 2: Cumulative average intake Never drinker 3 5836 1.39 (0.44-4.37) 1.60 (0.51-5.06) Former drinker 0 13418 NA NA NA NA 0.1-5g 155 604119 1.0 (ref) 1.0 (ref) 5.1-10g 8 99342 0.32 (0.16-0.65) 0.40 (0.20-0.82) 10.1-30g 29 134479 0.84 (0.56-1.25) 0.99 (0.65-1.51) > 30g 10 34737 1.09 (0.57-2.07) 1.04 (0.52-2.07) Exposure model 3: Most recent alcohol intake Never drinker 3 14507 0.67 (0.21-2.11) 0.73 (0.23-2.30) Former drinker 4 31215 0.46 (0.17-1.25) 0.43 (0.16-1.17) 0.1-5g 152 562964 1.0 (ref) 1.0 (ref) 5.1-10g 9 101413 0.34 (0.17-0.66) 0.42 (0.21-0.83) 10.1-30g 27 122877 0.82 (0.55-1.24) 0.97 (0.62-1.50) > 30g 9 39106 0.88 (0.45-1.73) 0.83 (0.40-1.70) Model 1: Adjusted for age and total energy intake. Model 2: Adjusted for age, total energy intake, race, income, smoking status, pulse in 60 seconds, waist-to-hip ratio, and physical activity.