Of the 166 cases reported to the registry in 2005, 72% (120/166) were male and 28% (46/166) were female (Table 7a). These data are in keeping with long term trends in the gender distribution of U.S. cases (Table 7b). While the gender ratio can differ dramatically in various areas throughout the world, the 2:1 male/female ratio generally reported for this disease closely approximates that seen over the last 10 years in the U.S. (Figure 9).

The age distribution of U.S. cases in 2005 is summarized in Table 8a and over the last ten years in Table 8b. Further demographic breakdown of cases by age and gender is shown in the sub-part of each table. In 2005, the age of all registrants ranged from 6 to 93 years. Obviously, the age of attack varies markedly within the U.S., and all age groups are vulnerable to this disease. The majority of U.S. cases occur among middle-aged adult males. This general trend of a broad age range of attack has remained relatively consistent over the last ten years. Therefore, support services must be considered for patients of all age categories, and no particular age group should be considered more at-risk than another.