| male | female | all
fraction of US population | 1 in 17500 ≈ 0.0057% | 1 in 7400 ≈ 0.013% | 1 in 9800 ≈ 0.01%
number of US patients | 10200 per year | 33200 per year | 43500 per year
average patient age | 38 years | 65 years | 58 years
symptom sample size | 6 visits | 9 visits | 15 visits
(estimates based on 131748 patient visits to healthcare providers from NAMCS and NHAMCS, weighted for USA healthcare demographics, 2006 to 2007)