Fig 1. Association of caffeine intake with erectile dysfunction in NHANES 2001–2004 (n = 3724).

^†Adjusted for age, vigorous and moderate physical activity, smoking status, education, race/ethnicity, obesity (BMI ≥ 30 kg/m²), total water intake (plain and tap), total energy (continuous), alcohol (continuous). Error bars represent 95% confidence intervals. P _trend = 0.19. ^*Erectile dysfunction was defined as “sometimes” or “never” able to maintain an erection for satisfactory sexual intercourse. ^‡Approximately 170–375 mg/day of caffeine intake is equivalent to 2–3 cups of coffee.