Table 3.

Risk factors for chronic Q fever, Community A, Missouri, December, 2013

	Total, N = 135 n (%)	Cases, N = 47 n (%)	Low positive titers, N = 34 n (%)
Risk factor for chronic Q fever
Any risk factor*	18 (13)	6 (13)	4 (12)
Heart valve abnormality	10 (7)	5 (11)	2 (6)
Heart murmur	10 (7)	1 (2)	3 (9)
Aneurysm	1 (1)	0	0
Synthetic vascular graft†	0	0	0
Other medical history
History of injection drug use	26/130 (20)	10/45 (22)	5 (15)
Smoking in past 6 months‡	15 (11)	5 (11)	3 (9)
Current pregnancy	1 (1)	0	0
Pregnancy in past 6 months	4 (3)	1 (2)	1 (3)
Immunosuppressive medications	4 (3)	1 (2)	2 (6)

^*More than one risk factor may have been reported by an individual, but those with >1 risk factor were counted only once in the total.

^†Coronary artery stents or vein grafts associated with coronary artery bypass not included.

^‡Smoking was not permitted in Community A; therefore, so few persons reported having smoked in the past 6 months.