Table 4.

Associations of chronic fatigue syndrome^† (N=498) with medical conditions among controls (N=100,000)

Characteristics	Total	OR, 95% CI	Chi-squared p-value
Alcohol abuse	1,798	1.24 (0.68, 2.25)	0.489
Transfusion	5,252	1.98 (1.47, 2.66)	<0.0001
HIV infection	143	1.41 (0.20, 10.08)	0.732
Hepatitis B virus infection	225	2.71 (0.86, 8.50)	0.075
Hepatitis C virus infection	291	2.80 (1.04, 7.54)	0.033
Lupus	214	1.89 (0.47, 7.62)	0.364
Sjogren's syndrome	197	4.17 (1.54, 11.26)	0.002
Rheumatoid arthritis	2,514	3.05 (2.17, 4.29)	<0.0001

Abbreviations: N = number; OR = odds ratio; CI = confidence interval; ICD-9 = International Classification of Disease, 9th edition; HIV = Human immunodeficiency virus

^†CFS1, ICD-9 300.5 or ICD-9-CM 780.71 (1992–2005)