Table 1. Demographic characteristics of 2,872 deployed U.S. military personnel who completed the voluntary respiratory infection questionnaire Jan 2005 to Jan 2006.

Characteristic	Frequency	Percent
Age in years, mean (range)	29.1	(19–59)
Gender
Male	2,473	86.8
Female	339	13.2
Rank
E1–E4	1,446	50.9
E5–E6	926	32.6
E7–E9	210	7.4
Officer/CWO	261	9.2
Duty Status
Active duty	1,346	47.7
Reserve/Guard	1,477	52.3
Operation
Iraqi Freedom	2,015	71.4
Enduring Freedom	513	18.2
Both	271	9.6
Neither	25	0.9
Branch
Army	2,450	86.0
Air Force	56	2.0
Marine Corps	187	6.6
Navy	141	5.0
Other	16	0.6
Unit type
Command/support	1,479	52.4
Ground	961	34.1
Other	382	13.5
Prior deployment	739	26.2
Latrine type
Flush	1,885	68.5
Chemical/burn	832	30.2
Bag/trench/other	34	1.2
Cigarette smoking
None	1,782	67.4
1/2 pack/day	436	16.5
1 pack/day	333	12.6
>1 pack/day	92	3.5
Questionnaire site
Kuwait	342	12.0
Qatar	2,434	85.3
Turkey	79	2.8
Days in theater, mean (range)	164	(1, 826)