Table 4.

Estimates of total burden of illness among registrants 18 years of age and older, based on prevalence of reported health problems in the WTCHR and estimates of populations eligible for WTCHR enrollment^a

Parameter	Lower boundb	Midpointc	Upper boundd
Any new or worsening respiratory symptom
Rescue–recovery workers and volunteers	32,300	41,200	61,800
Building occupants, passersby, and people in transit	86,600	112,400	161,500
Residents south of Canal St.	5,900	7,600	8,900
Total	124,800	161,200	232,200
Newly diagnosed asthma
Rescue–recovery workers and volunteers	1,100	1,600	3,700
Building occupants, passersby, and people in transit	2,400	3,700	8,300
Residents south of Canal St.	300	400	600
Total	3,800	5,700	12,600
Serious psychological distress
Rescue–recovery workers and volunteers	1,700	2,500	3,400
Building occupants, passersby, and people in transit	7,700	11,400	16,000
Residents south of Canal St.	300	400	600
Total	9,700	14,300	20,000
Probable PTSD
Rescue–recovery workers and volunteers	7,300	10,600	13,700
Building occupants, passersby and people in transit	26,500	38,000	54,700
Residents south of Canal St.	800	1,100	1,800
Total	34,600	49,700	70,200

^aBurden estimates are rounded to the nearest hundred.

^bLower bound estimate adjusts for the possibility that even among listed persons, those ill were 50% more likely to enroll in the WTCHR. The lower bound estimate is the product of the total population exposed and the ratio of A to B, where (A) is the number of list-identified persons who were ill and (B) is the sum of the number of list-identified persons who were healthy ×1.5 and the number of list-identified persons who were ill.

^cMidpoint estimate is the product of the percent ill among list-identified persons and the total population exposed

^dUpper bound estimate is the product of the percent ill among self-identified persons and the total population exposed