Development of a Physiological Frailty Index for the World Trade Center General Responder Cohort

Table 2

Summary of demographic and exposure characteristics of the study sample.

Characteristics	Summary statistics
Sample size	7346
Age at 9/11 (median, IQR, range)	39 (34–45, 25–74)
Age at index visit (median, IQR, range)	51 (46–57, 40–85)
Sex
Female	1229 (16.7%)
Male	6117 (83.3%)
Race/ethnicity
White	3983 (54.2%)
Black	1084 (14.8%)
Hispanic	2100 (28.6%)
Other	179 (2.4%)
Smoking status at index visit
Never	4484 (61.0%)
Former	2289 (31.2%)
Current	573 (7.8%)
Pre-9/11 occupation
Construction	1781 (24.2%)
Protective	3466 (47.2%)
CM and IRG	709 (9.7%)
Other	1390 (18.9%)
WTCHP enrollment year
2002–2005	3594 (48.9%)
2006–2008	2296 (31.3%)
>2008	1456 (19.8%)
Index visit year
2012	1574 (21.4%)
2013	2399 (32.7%)
2014	2693 (36.7%)
2015	468 (6.4%)
2016	212 (2.9%)
Educational attainment
High school or less	2263 (30.8%)
>High school	5083 (69.2%)
Exposure severity
Low	990 (13.5%)
Intermediate	4793 (65.2%)
High/very high	1563 (21.3%)

: cleaning/maintenance of buildings and grounds; IRG: installation/repair groups (electrical, telecommunications, and others); : WTC Health Program.