Table 3.

Mulitvariate analysis of factors associated with persistence of individual symptoms in persons infected with West Nile virus, Idaho, 2006–2008^*

Factors	Signs and symptoms
	Fatigue	Muscle aches	Decreased activity	Difficulty with memory	Difficulty concentrating	Balance problems
Neuroinvasive disease	1.5 (0.7–3.1)	2.1 (0.9–4.8)	3.3 (1.5–6.9)	1.2 (0.6–2.6)	1.0 (0.4–2.2)	2.9 (1.3–6.7)
Age (per year)	1.02 (0.9–1.04)	1.0 (0.99–1.04)	1.03 (1.00–1.05)	1.01 (0.99–1.03)	1.01 (0.99–1.04)	1.03 (1.0–1.06)
Female sex	2.0 (1.0–3.7)	1.3 (0.6–2.7)	1.6 (0.8–3.3)	1.4 (0.7–2.7)	1.7 (0.9–3.4)	2.1 (0.9–4.7)
Hypertension or diabetes	2.6 (1.3–5.0)	2.1 (1.0–4.6)	2.8 (1.4–5.6)	1.9 (0.9–3.8)	1.7 (0.8–3.6)	2.5 (1.1–5.6)
Time since infection (months)	1.1 (0.98–1.2)	1.0 (0.9–1.1)	1.0 (0.9–1.1)	1.1 (0.9–1.2)	1.1 (0.99–1.2)	1.0 (0.8–1.1)

^*Values are odds ratios and 95% confidence intervals. Values in bold are statistically significant (P < 0.05).